Contactor control system

In a control system used with an electromagnetic contactor having contact tips connected intermediate a source of alternating current and a load, opening and closing of the contact tips being controlled by removal and application of electrical power to a contactor actuating coil, a method of reducing multiple re-ignitions comprising the steps of:

• (a) providing a regulated source of electrical power;
• (b) coupling the regulated power source to the coil through controllable switching means;
• (c) monitoring the alternating current through the contact tips;
• (d) developing a zero crossing signal each time that the alternating current crosses a zero reference;
• and
• (e) automatically adjusting opening of the contact tips in coordination with the zero crossing signals whereby the contact tips separate within a predetermined non-zero phase angle prior to a zero crossing and after an immediately preceding zero crossing.

A method for determining contact tip opening in a contactor control system for an electromagnetic contactor having an actuating coil and at least one set of contact tips which open in response to removal of electrical power from the actuating coil, the method comprising the steps of:

• monitoring voltage on the actuating coil;
• identifying a first voltage peak in the monitored voltage subsequent to removal of power from the actuating coil;
• and
• detecting occurrence of a second voltage peak following the first voltage peak, the second voltage peak occurring substantially coincidental with contact tip opening.