This energy must be dissipated safely from the winding after the test current is stopped. Hydro Generator Test and Inspection Condition Assessment Service Winding Resistance* X X X Visual Inspections (See Table 2) X X X Wedge Tightness Checks X RTD Resistance* X • Rotor AC Drop Voltage Test - to identify shorted turns in rotor poles. Exciter (brushless): visual inspection, insulation resistance test. and exciter rotor windings. The tests/inspections above can be completed in about 12 hours and can reveal imminent faults in the winding of the stator and rotor. Stator insulation testing. A "tight" stator winding can last two or three times as long as a winding that is not firmly held in the stator core. 1 lists the recommended tests for stator and wound rotor windings. But in practice, it is not possible. In cases where resistance goes down, we would suspect shorted turns. ROTOR WINDINGS RESISTANCE VALUES Single Capacitor 3. 2 Components of Current for Insulation Resistance Test 19 3 Insulation Resistance With Time for Different Insulation Class B insulation and 80' C temperature rises fot Class IB field-winding insulation (American National Standards 1977, 1982), until recently, no Corps. Check for burnt, damage to body or cooling fan or shaft. The insulation resistance measurement system of the MRR1 can be used for synchronous genera-tors of both types, with and without brushes. Temperature winding factor. Consult the motor schematic or a diagram of the motor's windings and use the meter to measure the resistance of the windings. Bump test (optional) 26 Several robots to fit a broad range of generator types. A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. Generator Testing & Inspection Services. Test Points - Resistance Tests TEST 9 - TEST THE STATOR Discussion Test Point A Test Point B Stator Lead Blue Wire Stator Lead Black Wire This test will use a Volt-Ohm-Milliammeter (VOM) to test the stator windings for the following faults: Stator Lead Blue Wire C1 Pin 3 (White Wire). The electronic smell is often the sweet skunk odor of carcinogenic epoxy fumes. 1 lists the recommended tests for stator and wound rotor windings. The purpose of this test at induction motor testing is to measure the resistance of stator, rotor and exciter windings to ensure that the values calculated at 20°C (ambient) conforms to the technical specifications. If the neutral connection is available and can be opened, measure the resistance between phases. Reliable Turbine Services offers top quality generator inspection services through our GATE 1-2-3 program. Mechanical stress in rotor windings cause inter turn faults (short circuits), which can lead to magnetic imbalance in generators and motors. It consists of a coil of wire through which a current flows. Both technicions. Temperature winding factor. In a winding system, most OEM's recommend a PI value of 1. During the measurement and immediately afterwards, some of the terminals. However, I have seen alternators that can have the correct ohm reading, but not put out ample current (Wattage). (2) Generator and excitation system test. This article covers the IR, winding resistance and surge tests. Measure the resistance to ground of the stator and field windings. I need to test my portable Generator's Stator. Rotor Winding Most of the synchronous motors used in the air separa-tion business have salient pole rotor windings with 4–26 poles. When an electric current flows though the wire, a magnetic field is induced inside the coil of wire. Second generation (2007-2020) / Honda Fit 2007-2020 Repair Manual / Electrical / Charging / Alternator / Generator / Alternator Overhaul / Rotor Slip Ring Test Measure the resistance between the slip rings (A):. Then remove the field winding from ground and connect to the (-) Line connection on the megohmmeter. The meter should not show an "open" or a "short" when a winding leg is measured. For example, if a coil develops a short circuit, a thermal bend may develop due to an asymmetric heat input into the rotor. The test voltage on rotors is typically 500 V dc (the diodes should be disconnected before performing the test). If the fault stays in the same phase then the fault is in the windings. Temperature winding factor. 43-2000, drastically changed a number. It is the simplest and most convenient test method. Disconnect all leads to voltage regulator and all other points to completely isolate the winding before meggering. Broken amortisseur winding bars. Who is correct? A. Measuring Exciter Armature Winding Resistance REMOVING AND INSTALLING GENERATOR ROTOR. † Connect one test lead to the rotor shaft and the other. Both the 100% and 80% test levels are limited to one-time tests of a winding. Alternator Winding Temperature Rise in Generator Systems When a wire carries electrical current, its temperature will increase due to the resistance of the wire. One component of this assessment is the wedge tightness or wedge tapping test that examines the tightness of the stator slot. Cold Winding Resistance Test. Separately test the main field and stator windings. Also connect an (AC) frequency meter. 2) designed to mimic a 600 MW turbo-generator rotor is used for validation and testing of the presented thermal mapping method (constructional details given in Table 1). I think it is bad due to reverse feedback. (This test should be performed with the generator running. What you need is a three phase variac 440V 50 Hz or 460V 60 Hz for this test. Insulation Resistance Test (Includes Line and Neutral Together to Earth and Between Live Conductors) - Duration: 9:08. A very low resistance indicates a shorted rotor. IEEE Standard No. Measuring Generator Field Winding Resistance C. Measure the resistance to ground of the stator and field windings. 3) • Clause 6. I have asumed the rotor is ok. The test is done on the motor to find the resistance (R1) of the stator is named as dc test of induction motor. The empirical data. The meter should read between four and eight volts AC. This cycle is repeated 60 times for 60 hertz AC power. One turn short due to damaged insulation may result in no variation in resistance. V-blocks between each pole keep the rotor windings in place. Ideally, this resistance should be infinite. In a winding system, most OEM’s recommend a PI value of 1. 43-2000, drastically changed a number. Installing Rotor Section 10 Tables and Figures. The power comes from the stator windings. The armature windings conduct AC even on DC machines, due to the commutator action (which periodically reverses current direction) or due to electronic commutation, as in brushless DC motors. Resistances go up when braze joints start to fail, or when silver plated surfaces degrade. The main purpose of this test is to check for gross differences between windings and for opens in the connections. Alternator Winding Temperature Rise in Generator Systems When a wire carries electrical current, its temperature will increase due to the resistance of the wire. I need to test my portable Generator's Stator. The tests/inspections above can be completed in about 12 hours and can reveal imminent faults in the winding of the stator and rotor. Always test motors for grounded windings before replacing them. A major overhaul of the generator should be done every 8 years. If you still want to try to testwinding to winding short. Section 3 INSULATION RESISTANCE TESTS Stator Leads 2 & 6 = Stator Excitation Winding Leads 11S & 22S = Voltage Sensing Leads Leads 11 & 22, 33 & 44 = AC Power Windings Figure 3-2. generator is made up of six major components: main stator (armature), main rotor (field), exciter stator (field), exciter rotor (armature), rectifier assembly, and voltage regulator. One ampere (amp) will flow when one volt is applied across a. Armature Winding Polarization Index Testing. In a generator, the stator output current is induced to flow in the copper conductors as a reaction to the. During the measurement and immediately afterwards, some of the terminals. Always test motors for grounded windings before replacing them. Windings are used in transformers and in rotating machines: i. If subsequent high-potential tests are desired (or for reconditioned windings), AR100 suggests testing at a 65% of maximum (new winding) level. In a winding system, most OEM's recommend a PI value of 1. Because the rotor winding is often sup-plied from a dc "exciter," the following also makes reference to. Electric generator - Electric generator - Stator windings: The maximum value of flux density in the air gap is limited by magnetic saturation in the stator and rotor iron, and is typically about one tesla (weber per square metre). Measuring Generator Field Winding Resistance C. This non-invasive test of winding resistance helps to pinpoint problems regarding windings in stator or rotor part of an electrical machine. generator case. The rotor winding to ground test results was infinity, that's means from rotor shaft to slip ring, the circuit was open circuit, if i got any reading on the meter that's means it was some problem on rotor winding. Static testing of motors is a full winding test that includes winding resistance test, meg-ohm test, polarization index (PI), di-electric absorption (DA), step-voltage test and surge test. I've already replaced the bridge amplifier. It is normally performed using a battery- or mains-powered megohmmeter. (It takes time for charges to pass through a resistance, and a voltage is created as the charges accumulate) This is an inductive spike. Similarly the range of Ammeter and voltmeter during blocked rotor test, 10A, 250V. Before conducting a transformer winding resistance test, it is important to observe all safety warnings and take proper precautions. However, I have seen alternators that can have the correct ohm reading, but not put out ample current (Wattage). We specialize in winding resistance testing, failure analysis, borescope inspection, AC. 3) • Clause 6. This causes higher shaft vibrations, resulting in stress and damage to the bearings. 5Ω, theactual. Generator Testing Programs It provides insight into how the insulation is absorbing charge or polarizing, and is used as a rough indication of the condition of the insulation. So we must let it cooling down until reach 60 °C to 40 °C before perform insulation resistance test. I need to test my portable Generator's Stator. A full set of. Rotor winding resistances (mil-Ω) as measured at 70oF. The empirical data. If subsequent high-potential tests are desired (or for reconditioned windings), AR100 suggests testing at a 65% of maximum (new winding) level. - Stator Leads TESTINg ROTOR INSULATION To test the Rotor for insulation breakdown, proceed as follows: Disconnect wires from the Rotor brushes or. Connect the variac to the stator with rotor out. The rotor is then turned by external means producing a rotating magnetic field, which induces a 3-phase voltage within the stator winding. The test can be applied to stator and rotor windings on asynchronous motors, stator and rotor windings on synchronous motors and the armature and field windings on DC motors. The generator field is the rotating magnet of the generator. Winding resistance measurements are an important diagnostic tool for assessing possible damage to transformers resulting from poor design, assembly, handling, unfavorable environments, overloading or poor maintenance. ** Perform front-to-back resistance tests on diodes and gating tests of silicon-controlled rectifiers?for field. PROCEDURE: To obtain short circuit current and its power factor angle, block rotor test is. The following…. Before and after the test, the insulation resistance of the stator winding was measured using a water-cooled generator-specific shake table. This is probably the most widely used diagnostic test for motor and generator rotor and stator windings. If it is a cast aluminum rotor the shorting ring and the rotor bars are cast at the same time and no connecting joints exist. Insulation Resistance test measures the resistance of the electrical insulation between the copper conductors and the core of the stator. Circuit shown below is for Blocked Rotor Test to obtain more reliable values ranges of both wattmeter should be 10A, 250V for Blocked Rotor Test. If the insulation fails to meet the test standards, the generator may be dried out by heat from a. like as the name says, testing the generator to see if the alternator is toast. A GUIDE TO LOW RESISTANCE TESTING Understanding and Measuring Low Resistance to Ensure Electrical System Performance WWW. Apply rotor voltage between the copper conductors and the rotor structure to eliminate the insulating effect of the bearing lubricant film. Would have to have a lot of windings shorted to see it with ohm meter. Disconnect all leads to voltage regulator and all other points to completely isolate the winding before meggering. The “megger” part of the test consists of applying a steady DC voltage to the winding under test. First do an ohms test on the stator using your bikes manual. Installing Rotor Section 10 Tables and Figures. Damper windings consist of copper or aluminum rods that are inserted through each pole surface and are brazed to copper or aluminum damper end plates at each end of the lamination stack. How to Check the Motor Winding Resistance by William Hirsch Updated March 16, 2018. When touching the probes to the terminals, there is no specific direction the probes need to be placed. 25 or higher on a rotor winding, and 2. Insulation resistance testing is performed when troubleshooting electric motors and related equipment. TGR test: insulation resistance, polarization index, winding resistance, impedance test. Motor or generator windings can store a large amount of energy when DC current is injected into them during the test (known as inductive charging). They are insulation resistance (IR), winding resistance, growler, phase balance, surge comparison, polarity and ball rotation tests. Mechanical stress in rotor windings cause inter turn faults (short circuits), which can lead to magnetic imbalance in generators and motors. , an open winding or shorted turn), subtler problems can be detected. The field winding loss (I 2 R) at a specific load can be determined by noting that the resistance of the field winding will decrease by T. Alternator Winding Temperature Rise in Generator Systems When a wire carries electrical current, its temperature will increase due to the resistance of the wire. These tests are performed to check the electrical or mechanical defects of the induction motor. This causes higher shaft vibrations, resulting in stress and damage to the bearings. A zero or low reading is conformation that a ground exists. AR100 Section 4. The insulation resistance test consists of a measurement of the dc resistance between the winding and ground, or between two windings. An electrical induction motor contains windings, or wire wrapped around a cylindrical shaft. 8 ohms Dual Capacitor 4. Shorted stator windings. ** Perform a high-potential test on the excitation system in accordance with ANSI/IEEE Standard?421. Test Points - Resistance Tests TEST 9 - TEST THE STATOR Discussion Test Point A Test Point B Stator Lead Blue Wire Stator Lead Black Wire This test will use a Volt-Ohm-Milliammeter (VOM) to test the stator windings for the following faults: Stator Lead Blue Wire C1 Pin 3 (White Wire). Development and testing of rotor resistance control schemes. \$\endgroup\$ - user11355 Aug 9 '12 at 0:51. Also test for shorts between windings and between each winding and rotor core. Whereas, the rotor has low insulation. ROTOR WINDINGS RESISTANCE VALUES Single Capacitor 3. Stratton Power Products® "Portable Generator Rotor/Stator Resistance Tables Pub. To determine whether a 3 phase motor is still good or has gone bad, a simple ohmmeter test across the windings of the motor will reveal its true state of health. When testing a generator over 3500W, test the two blue wires for AC voltage. - DC Winding Resistance - Shorted Turn Detection - AC impedance - AC Pole Balance - Recurrent Surge Oscilloscope (RSO) Testing - Flux Probe Installation and Analysis. Generatortech, Inc. 80 and BCW. If we move the crank handle, deflecting torque is produced which indicates a resistance value. The AT4 can detect winding shorts in the rotor. When touching the probes to the terminals, there is no specific direction the probes need to be placed. If the winding's insulation wears away near the motor's case, the bare-wire winding shorts to. It is a high frequency meter th. During machine service a single turn-to-turn failure can hardly be detected: The reduction of the ohmic resistance of the field windings is small and thus the deviations in the exciter current are small, too, and these deviations usually are covered by other effects (e. A single ground fault does not affect the rotor and the generator but increases the stress to the ground in field when stator transients induce extra voltage & increases occurrence of second ground fault. Electric generator - Electric generator - Generator rating: The capacity of a synchronous generator is equal to the product of the voltage per phase, the current per phase, and the number of phases. In the test, a relatively high DC voltage is applied between the copper conductor and the stator or rotor core usually between the winding and ground as the machine core & body are grounded). Winding resistance rarely goes down—if things go bad, they usually go up. TGR test: insulation resistance, polarization index, winding resistance, impedance test. The high resistance of the rotor means either the rotor is bad, or the slip. A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. It works with a low frequency alternating test voltage (0,51 Hz, ±24V) which is connected via slip rings to the main excitor winding and to rotor earth (ref. [04] IEEE Recommended Practice for Testing Insulation Resistance of Rotating Machinery IEEE Std 43-2000. • Field windings are the windings producing the main magnetic field (rotor windings. Benefi ts: • Reveals pending faults in windings of the stator, rotor, and exciter. No further testing is necessary. (It takes time for charges to pass through a resistance, and a voltage is created as the charges accumulate) This is an inductive spike. If the resistance drastically varies, there could be a problem with the windings. BLOCKED ROTOR TEST 1. Make an insulation resistance test from the rotor winding to the rotor steel. This energy must be dissipated safely from the winding after the test current is stopped. Because the rotor winding is often sup-plied from a dc "exciter," the following also makes reference to. When testing a generator over 3500W, test the two blue wires for AC voltage. how to generator winding 20 kw generator exciter winding with new way - Duration: 14:30. Shorted rotor fields. If the fault stays in the same phase then the fault is in the windings. #87971 Rev 6 or later). Since these relationships independently determine the field winding resistance, by combining the ohms law relation with the properties of the material relation an operating temperature can be determined using the actual field voltage and shunt current. B ump Test of Generator Stator End Windings One of the tests to assess the condition of generator stator end windings is the performance of a bump test. For stators I just used a reactance meter. 5Ω, theactual. The rotor is then turned by external means producing a rotating magnetic field, which induces a 3-phase voltage within the stator winding. Check the resistance value of the rotating windings by placing the ohmmeter's probes across the two exposed leads. To assess the healthiness of a wire wound motor winding a simple test can be carried out in a repair shop where lack of proper testing instruments is normal in small shops. In electrical engineering, an armature is the component of an electric machine which carries alternating current. Both stator and rotor should pass a surge test. If the neutral connection is available and can be opened, measure the resistance between phases. TGR test: insulation resistance, polarization index, winding resistance, impedance test. True A ___ exciter is an AC generator and rectifier mounted on a motor shaft. Insulation Resistance Test (Includes Line and Neutral Together to Earth and Between Live Conductors) - Duration: 9:08. It's used to determine the voltage that should be applied to the field winding to generate a specific field current. The copper is a conduit for the stator winding current. It consists of a coil of wire through which a current flows. • Rotor Winding Tests: Insulation Resistance, Polarization Index, Cop-per Resistance and AC Impedance. When testing the windings od a single phase motor, Technician #1 says that the common and the run terminals show the lowest resistance. Balancing of current. This paper reviews the standards applicable for generator rotor winding hipot testing, and highlights the lack of any guidelines by IEEE on test levels for generator rotors that have seen service. Collector end of generator field RETAINING RING BORE COPPER MAIN TERMINAL FIELD COIL ENDWINDINGS COLLECTORS COLLECTOR TERMINAL MAIN LEADS AXIAL FAN A typical collecter end. As the RRE calculated, the rotor resistance using variables in stationary reference frame, the d-axis rotor-flux. For rotor windings, 500 VDC is the standard voltage. Non-invasive methods to assess the condition of insulation systems are typically limited to physical inspections, drawing inferences from a review of operating conditions and maintenance records, and from the results of on-line and off-line electrical testing. The test leads will be connected to two of the. Methods of Rotor Resistance Control. Amp - A measure of electric current flow. The turn insulation was then coated on one side with heat-cured glue, which required a bake cycle of the rotor after winding. Insulation resistance testing is carried out by applying a constant voltage to the equipment under test while measuring the flowing current. COM 99 Washington Street Melrose, MA 02176 Phone 781-665-1400 Toll Free 1-800-517-8431 Visit us at www. A 20 kVA mini-rotor (shown in Fig. 02 Technical Assistance (800) 343-1391 2 of 6 (1) Dew point temperature is the temperature at which the moisture vapor in the air condenses as a liquid. Winding resistance can be a comparison to an absolute number of Ohms or fractions of Ohms if the target resistance is known. DVM should = infinite resistance (no value, so to speak) for both tests. ZC-401A Generator Rotor AC Impedance Tester is a special instrument for determining whether the turn-to-turn short circuit exists in the generator rotor winding, and can manually and automatically (unidirectional or bidirectional) measure many parameters of the generator rotor such as voltage, current, impedance, power and rotating speed. Also for rotors, our high-speed balancing and testing helps ensure trouble-free mechanical and electrical performance. A GUIDE TO LOW RESISTANCE TESTING Understanding and Measuring Low Resistance to Ensure Electrical System Performance WWW. Firstly check the components of motor like. Measuring Exciter Armature Winding Resistance REMOVING AND INSTALLING GENERATOR ROTOR. This causes higher shaft vibrations, resulting in stress and damage to the bearings. Following this issue, the bedplate heaters for the generator were reconnected and placed back into service. The rotor is then turned by external means producing a rotating magnetic field, which induces a 3-phase voltage within the stator winding. Temperature rise in bearing. Disconnect all leads to voltage regulator and all other points to completely isolate the winding before meggering. The tests/inspections above can be completed in about 12 hours and can reveal imminent faults in the winding of the stator and rotor. It can also be a comparison of phase to phase resistances in a 3-phase motor or generator with a calculation of balance (or imbalance). Time-Resistance Testing Method This method is fairly independent of temperature and often. (2) Generator and excitation system test. • Winding Resistance – recorded to provide current winding resistance, which can be compared to prior tests for trending purposes. To prevent insulation damage, that means a winding may be subjected to each test level only once in its lifetime. Armature Winding Insulation Resistance Testing. A 'winding' is the term used in the electrotechnical industry for a coil of wire. The field winding loss (I 2 R) at a specific load can be determined by noting that the resistance of the field winding will decrease by T. Noticeably absent from this list is the ever popular high. Whereas, the rotor has low insulation. - DC Winding Resistance - Shorted Turn Detection - AC impedance - AC Pole Balance - Recurrent Surge Oscilloscope (RSO) Testing - Flux Probe Installation and Analysis. In the past two decades, the use of on-line testing of generator rotor windings has surged. how to generator winding 20 kw generator exciter winding with new way - Duration: 14:30. In practice, is not infinitely high. Synchronous Reactance. With the winding: connection still attached to the diode test between the con-nection and the metal of the rotor shaft as shown above, I check both sides. One ampere (amp) will flow when one volt is applied across a. Amperage - The strength of an electric current measured by amperes. Contents Generator Systems1 Generation System Basics2. During my review of the Megger MIT420/2 MIT420/2 insulation tester in Blog 9, I tested a 120MW Generator rotor winding that actually failed the insulation resistance test. Insulation Resistance Test (Includes Line and Neutral Together to Earth and Between Live Conductors) - Duration: 9:08. -Power Factor / Doble Testing. Generator Testing Programs It provides insight into how the insulation is absorbing charge or polarizing, and is used as a rough indication of the condition of the insulation. To assess the healthiness of a wire wound motor winding a simple test can be carried out in a repair shop where lack of proper testing instruments is normal in small shops. But smells like a triac to me. A huge spike in resistance could indicate that a wire is burned through or broken, interrupting the circuit. A major overhaul of the generator should be done every 8 years. V-blocks between each pole keep the rotor windings in place. Connect DVM lead to first brush lead in housing connector, other lead to the rotor shaft ground. I think it is bad due to reverse feedback. To calculate the resistance (R 2) of the rotor we should have the idea of R 1 (stator resistance) so that it can subtract from the total resistance. Test Method A (Section 3). • RTD Resistance – performed to ensure the resistance temperature detectors (RTD’s) are functioning properly in all slots. In today's we post will have look at working, equation, circuit and other. Cold Winding Resistance Test. Inspections, Electrical testing, Rewinds, Mechanical repairs and Retaining ring replacements are but of few of the tasks Keystone's experienced staff provides customers for generator rotors. Connections are made as per the circuit diagram. 3 above for one minute. To prevent insulation damage, that means a winding may be subjected to each test level only once in its lifetime. The results of the R r estimation obtained from the experiment is shown in Fig. Winding resistance can be a comparison to an absolute number of Ohms or fractions of Ohms if the target resistance is known. The CPC 100 can be used to perform DC winding resistance measurements on rotating electrical machines, such as generators and motors, to identify connection problems in stator and rotor windings. A motor fails when its windings short to ground, short to each other, or open--a break in the winding's wire. BASIC AC ELECTRICAL GENERATORS - 3 - As the South Pole moves away, the current in the winding decreases, returning to zero again when neither pole is close to the winding. The test is done on the motor to find the resistance (R1) of the stator is named as dc test of induction motor. I have asumed the rotor is ok. Instrumentation check 10. Test on insulation resistance and absorption ratio of generator stator and rotor windings Measuring insulation resistance is one of the contents of preventive test. Connect DVM lead to first brush lead in housing connector, other lead to the rotor shaft ground. This article covers the IR, winding resistance and surge tests. For most stators 13,800 and over, most OEMs call for 5,000 to be held for 10 minutes. This instability is identified as large changes in resistance or resistive imbalance values in back to back tests. When touching the probes to the terminals, there is no specific direction the probes need to be placed. Thanks for any advice. - DC Winding Resistance - Shorted Turn Detection - AC impedance - AC Pole Balance - Recurrent Surge Oscilloscope (RSO) Testing - Flux Probe Installation and Analysis. Check that the windings are not open or blown. how to generator winding 20 kw generator exciter winding with new way - Duration: 14:30. Connections are made as per the circuit diagram and rotor is blocked from rotating. But smells like a triac to me. BLOCKED ROTOR TEST 1. If you feel the resistance test is not stabilizing, contact PdMA® technical support for further clarification. Insulation resistance testing is carried out by applying a constant voltage to the equipment under test while measuring the flowing current. I've already replaced the bridge amplifier. TGR test: insulation resistance, polarization index, winding resistance, impedance test. In a rotating machine, the field coils are wound on an iron magnetic core which guides the magnetic field lines. Similar to sweep frequency response analysis (SFRA), the pole drop test is performed on single pole windings when the. Connect DVM lead to first brush lead in housing connector, other lead to the rotor shaft ground. ** Perform front-to-back resistance tests on diodes and gating tests of silicon-controlled rectifiers?for field. Perform insulation-resistance tests on the main rotating field winding, the exciter-field winding, and the exciter-armature winding in accordance with ANSI/IEEE Standard 43. (2) Generator and excitation system test. Shorting rings are commonly referred to as end rings. Damper windings consist of copper or aluminum rods that are inserted through each pole surface and are brazed to copper or aluminum damper end plates at each end of the lamination stack. The reason for the difference lies in the fact that most generator rotors are an "open" insulation system, with naked conductors in the end winding potion and thus it is expected to tolerate lower insulation. Winding resistance measurement (WRM) on power transformers is one of the most common transformer tests and covered in numerous international standards e. Check for burnt, damage to body or cooling fan or shaft. like as the name says, testing the generator to see if the alternator is toast. Who is correct? A. 8 ohms Dual Capacitor 4. -Power Factor / Doble Testing. Instruction Manual Installation Operation Maintenance Two Bearing KAMAG Generator with Outboard Exciter B. The synchronous machine tests give the induced voltage and the current when armature reaction is greatest, for a range of field current values. The insulation resistance and polarization index tests of an electric motor or generator has been regarded as a useful tool in evaluating its windings for buildup of dirt or moisture, deterioration. If their two wire ends are led out to the outside of the generator enclosure, should were measured in each of the windings between the insulation resistance of the insulation. 'Winding resistance' is. Applied voltage is increased until rated load current flows. The rotor bars are welded, brazed, or bolted to the end rings. Also for rotors, our high-speed balancing and testing helps ensure trouble-free mechanical and electrical performance. Set your multi-meter to test resistance. 43, Recommended Practice for Testing Insulation Resistance of Rotating Machines was introduced, but it wasn't until 2000 that the standard received a long overdue facelift. Test run the assembled motor with each set of 3 leads, and use a tachometer to determine the rpm. The test is done on the motor to find the resistance (R1) of the stator is named as dc test of induction motor. Since these relationships independently determine the field winding resistance, by combining the ohms law relation with the properties of the material relation an operating temperature can be determined using the actual field voltage and shunt current. Stratton Power Products® "Portable Generator Rotor/Stator Resistance Tables Pub. Supply is given by closing the DPST switch. and rotor have the same circuits, or a different number of circuits. What you need is a three phase variac 440V 50 Hz or 460V 60 Hz for this test. We specialize in winding resistance testing, failure analysis, borescope inspection, AC. Recently I participated in a generator electrical test program. Winding resistance. Measure resistance of the field windings and compare this to the. The generator field is the rotating magnet of the generator. DC winding resistance measurement will not provide data on inter turn shorts. Conductors are cleaned, polished, inspected and tested, and if found suitable, repaired, straightened and re-arched. Generator windings, such as generator excitation system of synchronous generator stator winding, field winding brushless self reactor, current transformer windings. Understanding Insulation Resistance Testing (pdf) 02/06 Rev. phases of the stator in an AC motor/generator and between polarities of the rotor in a synchronous generator. This article covers the IR, winding resistance and surge tests. The practical implementation of the above rotor resistance estimation was found functioning very well in the experimental drive setup. Armature Winding Insulation Resistance Testing. 0 or better on a stator winding. To determine whether a 3 phase motor is still good or has gone bad, a simple ohmmeter test across the windings of the motor will reveal its true state of health. In the past two decades, the use of on-line testing of generator rotor windings has surged. Ideally this resistance is infinite, since after all, the purpose of the insulation is to block current flow between the copper and the core. DVM should = infinite resistance (no value, so to speak) for both tests. Generator Testing Programs It provides insight into how the insulation is absorbing charge or polarizing, and is used as a rough indication of the condition of the insulation. Measuring of Stator winding resistane is also of the mentioned tests. and our skilled technicians will take you through the required testing needed to provide a better than new rotor. The rotor winding to ground test results was infinity, that's means from rotor shaft to slip ring, the circuit was open circuit, if i got any reading on the meter that's means it was some problem on rotor winding. • Rotor Winding Tests: Insulation Resistance, Polarization Index, Cop-per Resistance and AC Impedance. A very low resistance indicates a shorted rotor. Because the rotor winding is often sup-plied from a dc “exciter,” the following also makes reference to. Development and testing of rotor resistance control schemes. Wound-rotor stator windings are not short-circuited; they are wye connected, with the free end of each winding connected to a slip ring. MULTI ELECTRO 21,290 views. When testing the insulation resistance of a winding, all other conductors, metalwork (stator and rotor) and auxiliary circuits such as those for thermistor protection and heaters should be connected to the frame with light wire (fuse wire will do), and the test voltage applied between winding and frame. Similar to sweep frequency response analysis (SFRA), the pole drop test is performed on single pole windings when the. TM5-6115-593-34 NAVFAC P-8-631-34 TO-35C2-3-463-2 NOTE Low insulation resistance may be caused by dirt or excessive moisture. Both the 100% and 80% test levels are limited to one-time tests of a winding. The copper is a conduit for the stator winding current. In a generator, the stator output current is induced to flow in the copper conductors as a reaction to the. of coils are 6 to 7 per pole. PROCEDURE: To obtain short circuit current and its power factor angle, block rotor test is. ; Calculation of winding temperature at the end of temperature rise test of transformer. IEEE Standard 43-2000, Recommended Practice for Testing Insulation Resistance of Rotating Machines, recommends the insulation test voltage to apply, based on winding rating, and minimum acceptable values for electric motor windings. One ampere (amp) will flow when one volt is applied across a. Whereas, the rotor has low insulation. One winding for single pahse 3 windings all connected together for 3 phase out put. 08 ohms Power Winding: Across 33 & 44 0. Ideally this resistance is infinite, since after all, the purpose of the insulation is to block current flow between the copper and the core. The exact location of the ground is difficult to predict, but on round rotor designs I have always found the problem to be under the retaining ring. They are insulation resistance (IR), winding resistance, growler, phase balance, surge comparison, polarity and ball rotation tests. In practice, is not infinitely high. Measure and compare the phase winding resistances. However, I have seen alternators that can have the correct ohm reading, but not put out ample current (Wattage). The chart at the right summarizes results from NEC's typical stator bar and coil data against the performance parameters of two internationally-respected standards, KEMA and IEEE. The book 87971 does not carry my model. MEASUREMENT OF STATOR RESISTANCE 1. systems for the generator stator, rotor, and stator core. If we move the crank handle, deflecting torque is produced which indicates a resistance value. Details about the tests were provided in Chap. Generator testing 2: 2 tests for generator rotor شرح - Duration: 3:17. A 20 kVA mini-rotor (shown in Fig. However, there are other simple methods of testing low resistance windings, which are included in the various test procedures, i. Control of power output of a Type-2 turbine can be accomplished by varying the rotor resistance. This surface PD causes bright white deposits on the stator coils, and is usually caused by poorly-made or poorly-applied partly-conductive and silicon carbide. Firstly check the components of motor like. During drying operations, when insulation resistance values are used as an indicator of the suitability of windings for service or for application of test potential, the drying must be continued for a sufficient time to make sure that the values are reliable. NEC can manufacture turbogenerator windings of any design. The rotor bars are welded, brazed, or bolted to the end rings. This energy must be dissipated safely from the winding after the test current is stopped. 8 ohms Dual Capacitor 4. This is probably the most widely used diagnostic test for motor and generator rotor and stator windings. Electric generator - Electric generator - Generator rating: The capacity of a synchronous generator is equal to the product of the voltage per phase, the current per phase, and the number of phases. regarded as a useful tool in evaluating its windings for build up of dirt or moisture, deterioration of the. Winding resistance measurement (WRM) on power transformers is one of the most common transformer tests and covered in numerous international standards e. Label one set as 1-2-3 and the other as 7-8-9. Just as you can apply 15% of rated stator voltage to perform an open stator ball test, you can apply 15% of secondary voltage to "ball test" the rotor. multimeter image by dinostock from Fotolia. In practice, the IR is not infinitely high. Time-Resistance Testing Method This method is fairly independent of temperature and often. For testing rotors I had used what we called as "growlers" when a winding short is sensed it gives that loud growling noise as I turn the rotor and hit a shorted winding. It's used to determine the voltage that should be applied to the field winding to generate a specific field current. When testing the insulation resistance of a winding, all other conductors, metalwork (stator and rotor) and auxiliary circuits such as those for thermistor protection and heaters should be connected to the frame with light wire (fuse wire will do), and the test voltage applied between winding and frame. Both the voltage and the current are the effective, or rms, values (equal to the. The AT4 can detect winding shorts in the rotor. - Stator Leads TESTINg ROTOR INSULATION To test the Rotor for insulation breakdown, proceed as follows: Disconnect wires from the Rotor brushes or. Noticeably absent from this list is the ever popular high. generator is made up of six major components: main stator (armature), main rotor (field), exciter stator (field), exciter rotor (armature), rectifier assembly, and voltage regulator. A zero or low reading is conformation that a ground exists. The book 87971 does not carry my model. Recently I participated in a generator electrical test program. Alternator Winding Temperature Rise in Generator Systems When a wire carries electrical current, its temperature will increase due to the resistance of the wire. V-blocks between each pole keep the rotor windings in place. It works with a low frequency alternating test voltage (0,51 Hz, ±24V) which is connected via slip rings to the main excitor winding and to rotor earth (ref. This causes higher shaft vibrations, resulting in stress and damage to the bearings. ** Perform an ac voltage-drop test on all rotating field poles. The order of resistance is in hundreds of milli ohms. - DC Winding Resistance - Shorted Turn Detection - AC impedance - AC Pole Balance - Recurrent Surge Oscilloscope (RSO) Testing - Flux Probe Installation and Analysis. For testing rotors I had used what we called as "growlers" when a winding short is sensed it gives that loud growling noise as I turn the rotor and hit a shorted winding. A reading of "infinity" or a very high resistance indicates an open circuit or a partially open condition in the rotor windings. Ideally, this resistance should be infinite. Reliable Turbine Services offers top quality generator inspection services through our GATE 1-2-3 program. • Field windings are the windings producing the main magnetic field (rotor windings. Measure resistance of the field windings and compare this to the. • Rotor Winding Tests: Insulation Resistance, Polarization Index, Cop-per Resistance and AC Impedance. This generator is extremely simple, with two separate windings on the rotor. generators and motors. 5 MVA / 3000 RPM - Winding resistance, the. DC ohmmeters are useless for testing transformer shorts, due to low dc resistance of normal windings. Electric generator - Electric generator - Generator rating: The capacity of a synchronous generator is equal to the product of the voltage per phase, the current per phase, and the number of phases. The measurement of insulation resistance is carried out by means of a megohmmeter - high resistance range ohmmeter. regarded as a useful tool in evaluating its windings for build up of dirt or moisture, deterioration of the. The empirical data. As described in the armature winding notes, synchronous reactance is a combination of armature winding leakage reactance and a reactance used to represent armature reaction. systems for the generator stator, rotor, and stator core. 0 ohms TESTING THE WINDING LEADS 5 Testing Continuity €heel,< that no continuity exists between either of the wind­. When testing a generator over 3500W, test the two blue wires for AC voltage. MULTI ELECTRO 21,290 views. The reason for the difference lies in the fact that most generator rotors are an "open" insulation system, with naked conductors in the end winding potion and thus it is expected to tolerate lower insulation. True A ___ exciter is an AC generator and rectifier mounted on a motor shaft. The magnetic core is in two parts; a stator which is. The insulation resistance and polarization index tests of an electric motor or generator has been. The copper is a conduit for the stator winding current. The turn insulation was then coated on one side with heat-cured glue, which required a bake cycle of the rotor after winding. The order of resistance is in hundreds of milli ohms. To calculate the resistance (R 2) of the rotor we should have the idea of R 1 (stator resistance) so that it can subtract from the total resistance. • Rotor Winding Tests: Insulation Resistance, Polarization Index, Cop-per Resistance and AC Impedance. By performing routine rotor testing you can better maintain uptime and avoid unscheduled outages. Rotor Testing Dependable Generator Uptime. 33 ohms might be hard to measure unless you use 4-wire ohm meter, (contact resitance variations can be as large as total resistance with 2 wire). As shown below, the indicated terminal matrix ( blue lines) shows the way the windings of a 3 phase motor should be tested with an Ohmmeter: #N#How to test the windings of a 3 Phase. Use the schematic and take readings of all of the windings. Insulation resistance testing is carried out by applying a constant voltage to the equipment under test while measuring the flowing current. 2) Determination of loss components must be performed in the following order:. - Stator Leads TESTINg ROTOR INSULATION To test the Rotor for insulation breakdown, proceed as follows: Disconnect wires from the Rotor brushes or. No further testing is necessary. Often the resistance curve will take one or more sharp dips before leveling off or. re: how to do 350kw generator megger test?? catserveng (Electrical) 17 Feb 16 04:25 Here is a very good manual with instructions on testing a generator, even if your generator is a different make the procedures and limits are reasonable for most any generator in your size range. of coils are 6 to 7 per pole. The test set uses a 16 VAC, 60hz signal to determine the AC load resistance in ohms. An insulation resistance measurement is one of the most basic and commonly employed tests used in the industry. • Winding Resistance – recorded to provide current winding resistance, which can be compared to prior tests for trending purposes. Discharge the field winding by grounding. The types of insulation used in rotating machines have continued to evolve and precipitate changes to insulation resistance testing since 1974 when IEEE Std. , an open winding or shorted turn), subtler problems can be detected. - Stator Leads TESTINg ROTOR INSULATION To test the Rotor for insulation breakdown, proceed as follows: Disconnect wires from the Rotor brushes or. Generatortech, Inc. The magnetic core is in two parts; a stator which is. Resistance for each winding should be 0. The test set uses a 16 VAC, 60hz signal to determine the AC load resistance in ohms. • Third stator winding resistance measurement (immediately after 6. Shorted stator windings. Static data results help define the motor's insulation integrity and aid technicians in predicting imminent failures before they become catastrophic. Synchronous Machine Rotor Windings the presence of faults in rotor winding insulation can sometimes be indicated by a change in machine performance rather than by the operation of a protective relay. regarded as a useful tool in evaluating its windings for build up of dirt or moisture, deterioration of the. 2 If the value of the one minute insulation resistance is between the values shown in Table 1A. 0 ohms TESTING THE WINDING LEADS 5 Testing Continuity €heel,< that no continuity exists between either of the wind­. The tests/inspections above can be completed in about 12 hours and can reveal imminent faults in the winding of the stator and rotor. Out of which 2 rotor windings are connected to X terminal (+ve) and the remaining two are connected to Y terminal (-ve). To assess the healthiness of a wire wound motor winding a simple test can be carried out in a repair shop where lack of proper testing instruments is normal in small shops. But smells like a triac to me. Synchronous Reactance. Re: Exciter Winding Resistance Unbalance 07/17/2018 10:05 AM If these measurements were taken with the windings separated and at the winding terminations, then it appears that either one of the coils was wired in series with its group, or a coil in a parallel group has a poor joint and/or has failed open. Similar to sweep frequency response analysis (SFRA), the pole drop test is performed on single pole windings when the. ** Perform an ac voltage-drop test on all rotating field poles. The revised standard, IEEE Std. • RTD Resistance – performed to ensure the resistance temperature detectors (RTD’s) are functioning properly in all slots. An AC motor consists of 6 terminals out of which 3 are rotor winding and the remaining 3 for stator winding. Complete rewinds-new or refurbished copper winding. The measurement of insulation resistance is carried out by means of a megohmmeter – high resistance range ohmmeter. In the test, a relatively high DC voltage is applied between the copper conductor and the stator or rotor core usually between the winding and ground as the machine core & body are grounded). This causes unbalance air gap fluxes which. Winding resistance can be a comparison to an absolute number of Ohms or fractions of Ohms if the target resistance is known. (a) Generator Stator. The tests/inspections above can be completed in about 12 hours and can reveal imminent faults in the winding of the stator and rotor. Also test for shorts between windings and between each winding and rotor core. Write down each. One winding for single pahse 3 windings all connected together for 3 phase out put. It can also be a comparison of phase to phase resistances in a 3-phase motor or generator with a calculation of balance (or imbalance). TestEquipmentDepot. 2 If the value of the one minute insulation resistance is between the values shown in Table 1A. Following this issue, the bedplate heaters for the generator were reconnected and placed back into service. 8 ohms Dual Capacitor 4. B ump Test of Generator Stator End Windings One of the tests to assess the condition of generator stator end windings is the performance of a bump test. Out of which 3 rotor. A zero or low reading is conformation that a ground exists. † Start the generator engine,let it stabilize and warm up. Polyphase Induction Motors and Generators Sponsor Electric Machinery Committee of the IEEE Power Engineering Society Approved 12 May 2004 American National Standard Institute Approved 9 February 2004 IEEE-SA Standards Board Abstract: Instructions for conducting and reporting the more generally applicable and acceptable tests of polyphase induction motors and generators are covered. Mechanical stress in rotor windings cause inter turn faults (short circuits), which can lead to magnetic imbalance in generators and motors. generators and motors. Electric generator - Electric generator - Stator windings: The maximum value of flux density in the air gap is limited by magnetic saturation in the stator and rotor iron, and is typically about one tesla (weber per square metre). surge test patterns, the motor is either a 2-speed 2-winding motor, or a skip-pole part-winding start. As shown below, the indicated terminal matrix ( blue lines) shows the way the windings of a 3 phase motor should be tested with an Ohmmeter: #N#How to test the windings of a 3 Phase. The results of the R r estimation obtained from the experiment is shown in Fig. Testing Generator Stator. To use this tester, let's forget about the voltage and current phase relationships in ac circuits, and just look at how alternating current alone is affected. 8 ohms Dual Capacitor 4. TESTING THE ROTOR FIELD WINDINGS k Use a thin waIled, deep well 7116" (Umm) socket and. Details about the tests were provided in Chap. Control of power output of a Type-2 turbine can be accomplished by varying the rotor resistance. ~~~ ROTOR WINDING RESISTANCE. BLOCKED ROTOR TEST 1. We specialize in winding resistance testing, failure analysis, borescope inspection, AC. The power comes from the stator windings. Armature Winding Polarization Index Testing. Generator testing 2: 2 tests for generator rotor شرح - Duration: 3:17. These tests are performed to check the electrical or mechanical defects of the induction motor. [04] IEEE Recommended Practice for Testing Insulation Resistance of Rotating Machinery IEEE Std 43-2000. The resistance. ~~~ ROTOR WINDING RESISTANCE. It can be applied to all machines and windings, with the exception of the squirrel cage induction motor rotor winding, which does not have any insulation to test. Field Windings Insulation Resistance Test Procedure IEC and ISO IEC and ISO Procedure H R A 9 Generator High Voltage tests of Armature and Field Windings Procedure IEC and ISO IEC and ISO Procedure H R A Inspection and Test Plan for Generator Before Manufacturing Activity By No. AR100 Section 4. The rotor bars are welded, brazed, or bolted to the end rings. Mechanical - Borescope Inspection - Terminal Stud Seal Pressure Test - Non-Destructive Evaluation Testing (NDE)—Rotor, Body and Rings - Collector Ring Inspection. In a winding system, most OEM's recommend a PI value of 1. ** Perform front-to-back resistance tests on diodes and gating tests of silicon-controlled rectifiers?for field. This non-invasive test of winding resistance helps to pinpoint problems regarding windings in stator or rotor part of an electrical machine. Ideally this resistance is infinite, since after all, the purpose of the insulation is to block current flow between the copper and the core. Balancing of current. Static data results help define the motor's insulation integrity and aid technicians in predicting imminent failures before they become catastrophic. Safety is an important consideration when testing winding resistance. Measuring Generator Field Winding Resistance C. Table 1 provides recommendations on test voltages. Perform insulation-resistance tests on the main rotating field winding, the exciter-field winding, and the exciter-armature winding in accordance with ANSI/IEEE Standard 43. To use this tester, let's forget about the voltage and current phase relationships in ac circuits, and just look at how alternating current alone is affected. The CPC 100 can be used to perform DC winding resistance measurements on rotating electrical machines, such as generators and motors, to identify connection problems in stator and rotor windings. If a resistance measurement is detected, there is likely a short to ground condition in the stator. rotor slots then shorted together at either end of the rotor using copper or aluminum "shorting" rings. When touching the probes to the terminals, there is no specific direction the probes need to be placed. These tests are performed to check the electrical or mechanical defects of the induction motor. Connections are made as per the circuit diagram. The insulation resistance and polarization index tests of an electric motor or generator has been regarded as a useful tool in evaluating its windings for buildup of dirt or moisture, deterioration. the poles are then electrically connected to the dc supply (normally up to a few hundred volts) in. The electronic smell is often the sweet skunk odor of carcinogenic epoxy fumes. Broken amortisseur winding bars. and exciter rotor windings. Thermal Stability Testing - involves changing generator-operating parameters (watts, vars, and cooling) and recording and analyzing the impact on rotor vibration signatures. and our skilled technicians will take you through the required testing needed to provide a better than new rotor. Ground insulation test of a motor. Measure resistance of the field windings and compare this to the. The results of the R r estimation obtained from the experiment is shown in Fig. In practice, the IR is not infinitely high. Then remove the field winding from ground and connect to the (-) Line connection on the megohmmeter. Hydro Generator Test and Inspection Condition Assessment Service Winding Resistance* X X X Visual Inspections (See Table 2) X X X Wedge Tightness Checks X RTD Resistance* X • Rotor AC Drop Voltage Test - to identify shorted turns in rotor poles. multimeter image by dinostock from Fotolia. Answer / nithin. winding resistance measurement is carried out using 4 wire resistance measurement, where the current supply clamps are applied separately to the voltage test prods. Both stator and rotor should pass a surge test. In the test, a relatively high DC voltage is applied between the copper conductor and the stator or rotor core usually between the winding and ground as the machine core & body are grounded). the poles are then electrically connected to the dc supply (normally up to a few hundred volts) in. TESTING OF STATOR WINDING 2. 19 taken from a heat-run test conducted on an induction motor. Apply rotor voltage between the copper conductors and the rotor structure to eliminate the insulating effect of the bearing lubricant film. Generator testing 2: 2 tests for generator rotor شرح - Duration: 3:17. Balancing of current. Connect the test leads of an AC voltmeter or a volt-ohm- millimeter VOM into a generator receptacle. Following this issue, the bedplate heaters for the generator were reconnected and placed back into service. The turn insulation was then coated on one side with heat-cured glue, which required a bake cycle of the rotor after winding. Technitian #2 only. A keyphasor probe is also utilised to determine the angular position of the mini-rotor. While this simple gen erator produces AC (alternating current), the current produced is not very large since the strength of the magnetic field is not very large. Scored rings or a bent rotor shaft indicates that the rotor needs to be replaced. Insulation Resistance Measurement 8. GENERATOR TESTING Tests should be done on the generator during the outage to monitor its condition and to ensure that it is in a satisfactory state for return to service, following maintenance. Resistance for each winding should be 0. GE Generator Rotor Design, Operational Issues, and Refurbishment Options COUPLING COIL SLOT RETAINING RING BALANCE PLUG FAN COLLECTOR RING COLLECTOR FAN Figure 2. The purpose of winding resistance test is to determine the following: Calculation of the I 2 R losses in transformer. how to generator winding 20 kw generator exciter winding with new way - Duration: 14:30. The single phase stator might have a resistance or 2 or 3 ohms or something of that order.