RC networks are used across the coils of the contactors,
to protect them from the undesirable transient voltages that are generated
during switching off of contactor coils. The induced transient voltage
surges can be several times the rated voltage of the coil and can damage
the coil of the contactor. These induced voltages also have a high frequency
of the order of several KHz and generate noise.
RC networks connected in parallel to the coils of the contactors effectively
suppress the surge voltages by absorbing the energy contained in the
transients and safely discharging them. The RC networks also filter
out the noise generated by the transients.
Hitech Electrocomponents Pvt Ltd can make custom designed RC networks for surge
suppression as per the customer’s designs. The capacitors used
are of high voltage withstanding capacity and the resistors are non-inductively
wound to insure against the pulse voltages.