This article describes how the machine s insulation is tested and the information.
Step voltage test electric motors.
The leakage current is.
A motor placed in storage may or may not work regardless of its physical appearance.
How to check an electric motor.
Step voltage test the step voltage test records the peak in rush and decay of current as each increase step in dc voltage is applied to the circuit.
That is with the same test connections and with the same test voltage applied for the same length of time.
Step voltage test has become an industrial standard in common use for field testing.
Therefore if we use dc test voltage we ensure that the dc test voltage is under root 2 or 1 414 times the ac test voltage so the value of the dc voltage is equal to the ac voltage peaks.
Dc step voltage test it is typically performed at twice line voltage plus 1000 volts.
Step voltage test this dc test is performed to a voltage that a motor typically sees during starting and stopping.
In this test there is a sudden breakdown of the insulation between about 5 6 and 6 5kv and the test is shut down at the end of step 7 at about 6500v because the acceleration in the measured current exceeded the roc limit from step 6 to step 7.
The dc voltage is applied to all three phases of the winding and raised slowly to a preprogrammed voltage step level and held for a predetermined time period.
The step voltage test is performed upon completi on of a successful polarization index pi test starting at the same voltage used for the pi test.
Electric motor testing is usuallly the first thing to be sacrificed when cutting back on operational expenses.
But smart companies understands is that what this means for maintenance programs is billions of dollars of lost revenue through increased motor repair costs downtime and waste in industrial and commercial companies.
Pump motor or a short control cable may be vital to a process in your plant.
As the step voltage test progresses every 60 seconds the voltage applied to the insulation system is increased in specific voltage increments which is determined by the user.
The test voltages governed by ieee are reflected in table ii.
The voltage is increased in a series of steps and the leakage current is plotted.
Experience is the best teacher in setting up the scheduled periods for your equipment.
4160v motor test voltage 9320v.
With the motor running check the running amps of the motor using clamp on meter.
From these ones it has evolved a test that implementing the high voltage d c.
The test allows the technician to observe how the insulation system responds to an over voltage stress.
For example for a 1500 v ac voltage the equivalent dc voltage to produce the same amount of stress on the insulation would be 1500 x 1 414 or 2121 v dc.
You should make these periodic tests in the same way each time.
Match up to the full load.
Minimum test value of the electric motor is 1 meg ohm 1 mω.
The first ones ieee 62 1958 eda test basis to the late ones.
A quick check out can be done with.
When a motor fails it is often difficult to see why it failed just by looking at it.
