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What should you do to locate the shorted point in the starting winding?
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How do you know if a three phase motor's winding is shorted?
You use a megger. This allows you to check what the condition of the insulation of the motor windings are. An ohms check on each phase should be an easy way if it reads OPEN then there's your bad phase. Otherwise there are diffrent types of 3 phase motors, could be the brushes, commutator, sliprings, many many things.
How do you wire star delta motor having no labels of wires?
You can't , without knowing which winding is which . 9 times out of 10 it will just trip your protection device if it's connected wrong . U need to watch for it starting i'n forward i'n star but when it kicks into delta goes i'n reverse . If u take the motor to a winding shop they should be able to identifie which winding is which .
Why interturn test is done to transformer?
The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being comsumed. Using LCR meter to determine these 2 values of each winding 1) DCR 2)inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted. The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being consumed. Using LCR meter to determine these 2 values of each winding 1) the DCR 2) the inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted.
When testing a power transformer with an ohmmeter which winding should have the largest ohmic value?
The higher-voltage winding has more turns (therefore its conductor will be longer) than the lower-voltage winding and, because it will carry less current, its conductors will have a lower cross-sectional area. Consequently, the higher-voltage winding will have a higher resistance than the lower-voltage winding.
What starting device is used on single phase fractional horsepower compressor motors?
A centrifugal switch is used on the starting winding of fractional HP motors. It is used to start the motor one the start winding and at a predesignated rotational speed the switch opens to de-energize the start winding and the motor carries on running on the run winding. Another device that should be on compressor motors is an unloader valve. Sometimes it is electrical driven and other times it is mechanical. It is used to used to unload the pressure from the compression cylinders. Without this pressure being unloaded the motor has to start against the pressure in the cylinder head and the added current draw on the motor is sometimes enough to trip the overload protection of the motor.
Why do you measure the winding resistance with a multimeter?
Actually, measuring winding resistance with a multimeter is an iffy situation at best. This is because the multimeter will not tell you if one of the turns is shorted, causing Q to drastically suffer, it will really only tell you if the winding is open, or if it is shorted to something it should not be shorted to, such as the frame. This is especially true for larger windings, in larger transformers and motors, because their DC resistance is so close to zero that you might not be able to tell if they are shorted or normal. Using a multimeter is a good start, to make sure that basics are covered, and it might tell you if the winding is dead shorted, but you need to know for sure what the expected DC resistance is, and you need to know that you multimeter is very good in the low Ohms scale.
Should a starting windings in the split phase motor fail to energise what would be the result?
what will be the result if the starting winding in a split phase motor fails
How can rotation be change of single phase motor?
With the starting winding disconneted the motor will start up in whichever direction it is spun. To make the starting winding operate the other way, it needs an inductor in series insead of a capacitor. Details depend on the motor, but the reactance of the inductor should match that of the capacitor.
What will happen to the primary winding if the secondary is shorted?
If the secondary is shorted, then it will appear that the primary is shorted as well. What happens depends on how well the protective device (fuse or circuit breaker) and transformer is designed. If the protective device is incorrectly designed, it is theoretically possible for the transformer to explode. If it is properly designed, and the transformer is also properly designed, there should be no damage at all - fix the fault - reset the trip - and you are back in business - although an inspection would probably be in order to check for latent damage.
How do you reverse rotation on furnace fan motor 120 volt?
The motor connection diagram should be on the inside cover plate of the motor's junction box cover. To reverse the motor direction just reverse the starting winding leads while leaving the running windings just as they are. The starting winding numbers are sometimes numbered 1 and 4.
How do you know if a three phase motor's winding is shorted?
You use a megger. This allows you to check what the condition of the insulation of the motor windings are. An ohms check on each phase should be an easy way if it reads OPEN then there's your bad phase. Otherwise there are diffrent types of 3 phase motors, could be the brushes, commutator, sliprings, many many things.
How do you wire star delta motor having no labels of wires?
You can't , without knowing which winding is which . 9 times out of 10 it will just trip your protection device if it's connected wrong . U need to watch for it starting i'n forward i'n star but when it kicks into delta goes i'n reverse . If u take the motor to a winding shop they should be able to identifie which winding is which .
Why interturn test is done to transformer?
The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being comsumed. Using LCR meter to determine these 2 values of each winding 1) DCR 2)inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted. The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being consumed. Using LCR meter to determine these 2 values of each winding 1) the DCR 2) the inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted.
Where can I find a sample of winding up letter?
A winding up letter should include reasons that a company has been delinquent towards their credit payments. It should contain a way to resolve the problem.
What should a bad motor read in ohms if it is bad?
If an Alternating Current (a/c) motor is bad. The resistance will read very hi as in an open winding. ie: meg ohms Or very low as in a shorted winding. ie: 0.01 ohms It must not read any resistance to the housing or shaft. The resistance between leads should be a reasonable value and can be determined with : electromotive force divided by inductance equals resistance. example: 215 volt alternating current with name plate full load amperes of 10 should read very near 21.5 ohms resistance between leads.
Will an ac unit run on modified sine wave?
The unit should run OK on a modified sine wave since motors are not that sensitive to the waveform. Efficiency might be slightly reduced.The real problem may be in starting the unit. If the input does not have enough power to allow the compressor to start properly and it stays running on the start winding, it could burn up the start winding. Checking the current input with a clamp-on style amp-meter should show if it is drawing excess current by running on the start winding.
When testing a power transformer with an ohmmeter which winding should have the largest ohmic value?
The higher-voltage winding has more turns (therefore its conductor will be longer) than the lower-voltage winding and, because it will carry less current, its conductors will have a lower cross-sectional area. Consequently, the higher-voltage winding will have a higher resistance than the lower-voltage winding.
