** Perform vibration test. 4. Wingard specializes in electrostatic epoxy powder coating of armatures, stators, and all other shaped lamination cores. The Bar-To-Bar Test is provided to test the Low impedance of the Series wound Armatures and Field coils of DC Traction Motors. Test the armature for grounds by using the test light circuit, which is a part of most modern factory- built growlers (fig. Remove the threaded ring under the drive gear and gently drive the armature out of the drive end cover. Now, I cannot tell what that field is rated for. The two jaws thus effectively form an electromagnet and a magnetic field appears across the jaws. Before the armature circuit resistance can be calculated, the motor must be set up in a way such that both the armature and the motor frame are not permitted to turn. Armature Growler Tester is an electrical device used for testing insulation of a motor for shorted coils. Field Testing the Armature. the SA200. Don’t miss any: if … The armature and shunt field resistances are 0.2 ohm and 195 ohm respectively. Following is the list of practice exam test questions in this brand new series: MCQ in in Power Generators, Sources, Principles, Applications. In electrical machines, the magnetic field is generated by a permanent magnet or electromagnet. The surge test can be used for DC windings as well. So putting voltage between the pickup and the frame should supply current to the armature and the field in series, and the locomotive should run on the track. As in permanent magnet designs, these axially-wound coils act in consort with soft iron pole pieces to focus a radial flux field through the armature’s voice coil, which is driven by a variable current to induce vibratory motion. (Readjust the power supply, if necessary, to maintain exactly 120Vdc). Armatures are inspected and tested to ensure they meet the manufacturer’s identified requirements. If the test lamp lights, the field is grounded. If they have grooves or feel pitted they need replacing. You can rest assured that your armatures are fully tested and ready to work. In most generators, the field magnet is rotating, and is a part of the rotor, while the armature is stationary, and is a part of the stator. is 50 A; field current at full-load 80% p.f. gear box etc. For Armature Control Method – While conducting, the field current is kept constant and the armature voltage is varied. If you disconnect the field first, you might get a speed up of the armature and then a real high current in the armature and could damage stuff. All armatures and fields are tested on fully calibrated and maintained ESW testers including our brand-new ESW model AT7000 and AT6000 armature testers. At the moment a DC motor is energized, before the armature starts to rotate, the armature current is limited only by the available kVA of the power supply. Cyndi Nyberg Former EASA Technical Support Specialist In the April 2007 issue of CURRENTS, we covered surge testing anomalies, speci.cally for AC windings. For DC motors the primary interest is the condition of the ground wall and turn insulation systems of the armature and field and the health of the DC drive supplying power to the motor. As for Ohm’s Law, E/R = I; winders use this frequently to evaluate shunt fields and to extrapolate the temperature rise of those fields. When placed on the armature or stator core of a motor the growler acts as the primary of a transformer and the armature coils act as the secondary. The Bar-To-Bar Test is provided to test the Low impedance of the Series wound Armatures and Field coils of DC Traction Motors. The effect of leading power factor on the voltage regulation of an alternator is. The fully-automated unit performs the required set of tests that motor manufacturing and rebuild shops need for … You can test the field coil resistance of your dynamo quite easily if you feel competent and have access to a multimeter with a resistance range on it. 4.4. Armature Reaction: The effect of armature flux on the main field flux in any machine is known as armature reaction. When an electric motor is broken, one suspect is the fiel coild of the motor stator. Armature reaction is the result of the armature flux on top of main field flux. The Bar-To-Bar Test is provided to test the Low impedance of the Series wound Armatures and Field coils of DC Traction Motors. Perform resistance tests on resistance temperature detector (RTD) circuits. The generated voltage is described by Eq. Generally, the DC motor includes two windings such as Armature winding as well as field winding. JEFF MOLLOY The Adventures of Jack Pine JEREMY HERNDL Speaking Space December 6 - 19, 2012 Opening Reception with artists in attendance: Thursday, December 6, 5 - 8 pm. The fully-automated unit performs the required set of tests that motor manufacturing and rebuild shops need for … A 3,600 V, 500 kVA, 60 Hz, 3-phase Y-connected generator on test yields the following results: Mechanical and iron losses is 10 kW; field current at full load 100% p.f. 0 3 1 lim ( ) 2 afd afo s L Z s s → ⎡ ⎤ = ⎣ ⎦ (12-9) The most direct way is to obtain the magnitude of the low-frequency asymptote of the transfer function Δ e fd ( s )/ Δ i d ( s ), measured during the direct-axis tests with the field open. EASA Senior Technical Support Specialist This article addresses electrical testing and inspection of installed 3-phase squirrel cage motors. MCQs: A 240 V, 17 kW d.c. shunt motor draws an armature current of 80 A at full load. 05-21-2005 12:19 AM. These markings can almost always be found on the outside can next to the terminals. The Baker WinTATS traction armature test system is a reliable, field-proven system for accurate, rapid testing of armatures in motor manufacturing and quality control operations. No explanation is available for this question! Generally, the DC motor includes two windings such as Armature winding as well as field winding. The armature copper loss is variable and depends upon degree of loading of the machine. 2260 Oak Bay Avenue. PART 3: MCQs from Number 101 – 150 Answer key: PART 3. This test can be done from the machine’s control. Step2: Repeat step 1 for each equally opposite pairs of Commutator bars. The Digital Armature Surge Tester with bar-to-bar test is a cost-effective solution to check the quality of Small to Large range of DC Traction Motors ideally suited for Railways. Variable resistance in the armature circuit or field circuit allows speed control. Admin. Bring variac to zero position and turn off the supply. A few of them include: 1) The current is drawn directly from fixed terminals on the stator without the use of brush contacts. The Digital Armature Surge Tester with bar-to-bar test is a cost-effective solution to check the quality of Small to Medium range of DC Armatures. So 12 volts to a 1 ohm field will be 12 amps. Implementing a predictive maintenance program takes a PM program to the next level. Testing is available at the following sites and times: Bellingham: Monday and Saturday 9 a.m. - noon and 1 p.m. - 4 p.m., at Civic Field, 1355 Civic Field Way, Bellingham, WA 98229 Blaine / Birch Bay: Tuesday, 9 a.m. - noon at Birch Bay Bible Community Church, 4460 Bay Rd, Blaine, WA 98230 Ferndale: Tuesday, 1 p.m. - 4 p.m. at Ferndale Events Center, 5715 Barrett Rd, Ferndale, WA 98248 Environmental test shakers derive their magnetic field from electromagnetic coils excited by a fixed DC current. Most large machines, however, have a rotating field and a stationary armature. This depends upon the number of turns of wire and the current passing through the wire. Perform resistance tests on resistance temperature detector (RTD) circuits. This "residual" magnetism remains in the Field pole pieces even after the engine has stopped. 06. The overlapping time domain of the current 05. The ground may be caused by frayed wires at the coil ends. Testing the Field Coils. The rpm on 120v would indicate whether the armature has been changed etc. Apr 6, 2018. Apply a load to your dc motor by varying the dynamometer control knob until the scale marked on the dynamometer housing indicates 3 lbf.in. Check for an armature shorted to ground with your VOM set to the HIGHEST resistance range. BAR-TO-BAR TESTING CONSIDERATIONS Armature bar-to-bar testing is relatively easy to do in the field and in the motor repair shop. Max. That might be over the field coils' rated current. Tom Bishop, P.E. Hz. The leakage reactance of a three-phase alternator is determined by performing. It can be a useful tool for evaluating armatures and some DC fields. If the field winding test indicates the field winding is good, you should continue the procedure and test the armature winding for continuity. The field of a synchronous generator is the winding to which the DC excitation current is applied. A typical Electric Motor Armature. DC provided to the armature generates North and South fields that are 90 electrical degrees from the stationary field. RE: Sneak Peek at my new F3B Winch. We provide rewind services and manufacture new armature assemblies for OEM’s around the globe. If windings are shorted together, the electro-magnetic fields cannot be created for that coil, causing the motor to run erratically or fail all together. Richard, if it is a shunt wound motor then it was designed to run with 115V on both the armature and the field. Then you will have one field wire connected to the pickup (as now), the other field wire connected to the ungrounded brush, and the other brush connected to the locomotive frame. Most test specifications in the automotive and transportation industry emphasize low frequen-cies (ie: below 1,000 Hz) while military vibration specifications normally call for testing out to 2,000Hz and electronics industry specs can go as high as 3,000 Hz. Chuck Yung EASA Senior Technical Support Specialist When testing DC armatures, whether incoming for repair or after completing a rewind, one question I often hear involves interpreting the surge test (or the high-frequency bar-to-bar test) results. TESTING FIELD COIL RESISTANCE. 2. A leading pf load on an alternator implies that its voltage regulation shall be. The armature resistance is 0.8 Ω and the shunt field resistance is 240 Ω. Hi all, how would I go about checking armature and field components for my 332AC loco? For 2 brush dynamos it's easy - Dis-connect the 2 wires F&D from the dynamo. Ronnie, of The Edge Pro, walking you through how to test armatures and fields. 167ohms. Test 2 Multimeter Test: Purpose: To check Continuity and Balancing of Armature. The growler has two haws which are coupled by a limb with an inductor on it which is fed AC. 2) The insulation of stationary armature winding is easier. Hz. The DC provided to the stator fields generate a constant North and South set of fields. 2-19). running: Armature and Field Power tests, DC Current Analysis, DC In-Rush/Start-Up tests, and Drive Input Tests. 2) Magnetic field developed in the field coil. There's a lot more to it, of course, which I learned from doing an internet search on "How electric motors work". Thanks, that explanation helps a lot. These are fitted to each end of the motor where the armature sits. The basic test procedure is: Open circuit the generator terminals. For a shorted armature test the Growler is an optimum way. running: Armature and Field Power tests, DC Current Analysis, DC In-Rush/Start-Up tests, and Drive Input Tests. Rotate the armature slowly, noting the reading. The armature winding interacts with the magnetic field formed in the air gap. read less than an ohm. Like the armature, the field coils are checked with a continuity tester. The armature winding test may show that an open has developed from the coil burning open or from a problem with the brushes. Basic “Growl” test function is the capability to place the armature windings adjacent to high strength magnetic field and check for shorted windings. The stationary armature-rotating field construction has many advantages. Auto generators need some magnetism to get started. 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. If they are smooth then they are fine. The best way to check brushes and armature is by inspection. Drive the machine at synchronous speed using an external mechanical system. of windings from each bar on the commutator, which loop around the iron stack teeth and connect to the next bar on the commutator. As the armature generates a torque and moves towards the appropriate North or … Bellingham Testing Site Schedule . 130ohms. 1) Number of turns of wire on the armature. In this webinar, you will learn about shaker systems, including the history of how LDS Shaker Systems came to be. The next time the generator starts up, the residual magnetism creates a small voltage in the Armature windings. The armature is the winding to which the load is connected. Each supplies electricity to recharge starting batteries and run accessories, but an alternator produces electricity by spinning a magnetic field (magnets) inside a stable bundle of wires, whereas a generator produces electricity by spinning the wire inside the magnetic field. A schematic diagram of a Connect the test equipment to Al and A2. 6. When the armature is placed in a magnetic field which has its own North and South poles, it is the push and pull of like and unlike poles that leads to the spinning. Max. Load testing is not requested, but is available for an additional cost if required. Free Practice With Testbook Mock Tests Test the Field coils for grounding: Ifthe field winding to ground test can be preformed (the field winding is not attached to the body of the starter motor). Most test specifications in the automotive and transportation industry emphasize low frequen-cies (ie: below 1,000 Hz) while military vibration specifications normally call for testing out to 2,000Hz and electronics industry specs can go as high as 3,000 Hz. As always if you've hit a snag or have another question call or email! 3. Same on start up. Place the positive probe on the field wire or brush, then the common probe on the body of the starter. The right size ohmmeter or a limited DC current and an ammeter can be used to check the armature (while the machine is in place). In the case of a gearmotor with a fairly high gear ratio, this could require a rather sturdy restraint. Measure the armature and field currents and is 70 A; resistance per phase of armature winding is 0.4 ohm. Tom Bishop, P.E. Series DC Motor Test Procedure: 1. #6. Do not run the engine for these tests. When they fail your machine. The Baker WinTATS traction armature test system is a reliable, field-proven system for accurate, rapid testing of armatures in motor manufacturing and quality control operations. 2) RECORD INCOMING DIAMETRICAL IRON MEASUREMENTS AND SHIMS 3) RECORD WINDING DATA 4) REWIND ALL SIX MAIN POLE COILS, U300 THERMO SETTIN EPOXY 5) BOLTED CONNECTIONS ON SHUNT COILS 6) ROAST, CLEAN AND RE-INSULAT SERIES WINDINGS 7) ROAST CLEAN AND RE-INSULATE INTERPOLE … In small generators, the field windings are often on the stator, and the armature windings are on the rotor. 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. Look at the bearings on the top and bottom parts of the casing to see if they show signs of wear. Turn, undercut, and balance the armature Test the armature and field coils after VPI New brushes New bearings Rebuilt brush holders New seals and gaskets New hardware Balance armature Run test the motor under no load condition. Field’s Test for Series Motors Objective Test Questions and Answers on D.C. Motors. For Field Control Method – While conducting, armature voltage is kept constant and the field current is varied. Slowly increase the field current and measure the open circuit terminal voltage. You can do a test of the field coil (the coil attached to the main body) by connecting a 6 volt battery in series with a 6v 3w bulb and the field coil wires. The no load speed, in rpm is. rogerflies. field current using the field rheostat to the value obtained in previous step if necessary. 2. Dazed and Confused. This condition is known as opera-tion in the armature range. The stator can be a rotating part (rotor) or stationary part (stator). Recall that rotor body is made of iron with slots in which armature conductors are placed. Verify operation of machine space heater, if applicable. ELECTRICAL TEST PROCEDURES FOR ARMATURES, STATORS AND MOTORS Allan Naegeli President Electronic Systems of Wisconsin, Inc. Racine, WI 53406 Presented to: Electrical Manufacturing and Coil Winding Asia '93 June 18-25, 1993 Shanghai-Shenzhen - Hong Kong Everyone producing electric motors, stator or armatures makes electrical tests at various