Contactor with Emergency mode BUT no wasted coil Power

2 posts / 0 new
Last post
Jeffkay's picture
Last seen: 14 years 11 months ago
Joined: Monday, July 16, 2007 - 21:40
Points: 90
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: ... R/-/1.html


ArcticFox's picture
Last seen: 14 years 8 months ago
Joined: Tuesday, June 12, 2007 - 14:08
Points: 1091
Re: Contactor with Emergency mode BUT no wasted coil Power

There are also "latching relays" which might be of interest to you.

Latching relay
A latching relay has two relaxed states (bistable). These are also called 'keep' or 'stay' relays. When the current is switched off, the relay remains in its last state. This is achieved with a solenoid operating a ratchet and cam mechanism, or by having two opposing coils with an over-center spring or permanent magnet to hold the armature and contacts in position while the coil is relaxed, or with a remnant core. In the ratchet and cam example, the first pulse to the coil turns the relay on and the second pulse turns it off. In the two coil example, a pulse to one coil turns the relay on and a pulse to the opposite coil turns the relay off. This type of relay has the advantage that it consumes power only for an instant, while it is being switched, and it retains its last setting across a power outage.

<table border="0" style="border:1px solid #999999; padding:10px;"><tr><td>
<a href="">[img]

Log in or register to post comments

Use code&quot;Solar22&quot; and enjoy 12% off for all solar Kits.

Who's online

There are currently 0 users online.

Who's new

  • flycutycatshop
  • JanJouke
  • Skutr469
  • Lokyee Tsai
  • earlr85944

Support V is for Voltage