The AF series Contactors from ABB utilise an electronic control coil which is unique and offers some key benefits for difficult applications. All Contactors rely on the voltage running through a coil to create a magnetic field, when the magnetic field is strong enough it will pull in the Contactor. However this is an analogue process and when the voltage is too low, and the magnetic field is not strong enough to hold the contactor closed, there is a bouncing or chatter effect. This can occur for example when a motor kicks in and there is a dip in the overall system voltage.