What is the advantage of using coil suppression?

Coil suppression helps protect sensitive equipment from the transient voltage (back EMF) generated from the coil during de-energization. Ametek Prestolite Switch offers optional suppression devices including a resistor, varistor, diode, diode & resistor. The user must take into account that the coil suppression will increase the release time which will reduce the life of the contactor.