Maximum allowed single dv/dt of film capacitors

Thread Starter

Padderick

Joined Jan 7, 2012
12
Hallo together,

I am working on a AC input filter and the filter capacitor we use is made for repetetively 100V/µs.
When we connect the input filter with a relais to the grid, which happens daily in the field,
the AC input filter voltage rises around 280V/µs for 2.5µs up to arround 750V.
In our case we use a 1µF capacitor and get a single current flowing of I=C*du/dt=1µF*280V/µs=280A for the time of 2,8µs.

Questions:

1) Which effects occur when a voltage is switched on to a capacitor by a relais, when the high current due to the dv/dt and the capacitance is flowing through the capacitor?
2) Does anybody of you know how to get the maximum allowed value?
3) Are there any design notes concerning the maximum allowed single pulses on film capacitors/ capacitors in general?
4) Do you know any thermal models of any film capacitors?


Thanks in advance.

Best regards,

Friendly2Earth
 
Top