You may want a 120V coil in a starter if say its controlled from another source. A common occurance of this would be where a regular every-day 120V photoelectric eye used to control outdoor lighting, is used to drive a contactor with a 120V coil which in turn can control a 3 phase lighting circuit..
Also it could be used where its preferred the control wiring is at a " safer" voltage.. safer as in being as low as possible.
I have a single phase starter controlling my pool pump, it has a 24V COIL,the reason for that the controls are outside in a sometimes damp shed, and sometimes are operated by people standing on barefoot on concrete..
Last edited by Rewired; 07/16/07 07:18 PM.