Impulse voltages withstand Levels of rotating a.c.Machines with form-wound stator coils.
Impulse Voltage test:
- 1.2μs a time-to-half-value of 50 μs and a peak value of the impulse voltage Up (around 30kVa.c).
This voltage shall be applied between terminal and earth of the coil. 5 pulses one after the other
with some duration in between two pulses;
- Impulse voltage to be applied between terminals of the coil @ 19kV peak with the front time of the
first voltage peak at the terminals of the sample coil shall be 0,2 micro second.
Break Down Test:
- Selected coil to be applied with a voltage of 14.2 kV at power frequency between conductor and ground for 1 minute and continue increasing the voltage
at 1 kV / sec until the coil breaks down.
- Coil shall be cut at overhang portion and inter turn voltage shall be tested. Voltage to be applied is 6Kv, the maximum voltage would be around 30kVa.c