Hi,

What are the basic differences between a normal AC reactor and a dV/dt filter ? I looking for the theory behind.

Thanks.

Bob

Hi bob
An AC reactor as added on the output of a drive, is designed to reduce the di/dt. This will reduce the peak currents on the output and in an installation, it will serve to also reduce the dv/dt because of the capacitance of the load.

A dv/dt filter will reduce the rate of rise of voltage on the output and with a reduced dv/dt, there will naturally be a reduced di/dt. The difference is that the dv/dt is not reliant on the capacitance of the load to determine the dv/dt.

Output reactors will usually be much larger than the dv/dt and the effective dv/dt will be much lower.

If the dv/dt filter limits the rate of rise of voltage to a very slow level, then it will offer similar results to the output reactor.
Best regards,