Contactor with Emergency mode BUT no wasted coil Power

Hi, Folks! Here is an idea I have been working on for my "Deep Cycle" electric motorcycle conversion... One thing that always bugs me about contactors is the fact that they waste energy just holding in the solenoid. And they cost a good buck for control of a lot of current. This method uses a 200+ amp, continuous rating, knife switch and a automotive door lock actuator. The switch is closed manually. Then, in the event of an emergency, 12-24 volts is momentarily applied to the actuator. The actuator is pulled in by a miniature DC motor, not a solenoid. When the actuator pulls in, it pops the knife switch open with great force. Since there is no longer any B+ for the vehicle, the motor actuator cannot pull in or out. The knife switch will need to be manually reset after the problem event is rectified. The video shows the device going through a cycle. I found the switch on E-bay for $20. The actuator is available for $5.50 ea. here: http://www.allelectronics.com/make-a-st ... R/-/1.html

VIDEO OF OPERATION HERE: http://www.youtube.com/watch?v=5ZmqjKvRay0