Main power switch choice

reikiman's picture

In another forum posting I mentioned a problem with the solenoid/contactor on my Lectra. The ratings on the contactor is 60v @ 300A continuous. I'd thought that would be sufficient for a 60 volt pack going through a 400A controller. But the solenoid is stuck in the ON position all the time, indicating the contacts have welded shut.

I did some research on alternatives. I did find some solenoid contactors which might be good. Such as Contactor, Albright #SW-200, 250 amp carry, 360 amp momentary, 1500 amp interrupt, 12 volt coil ... it's rated for 120 volts and enough amps to handle what my Lectra will be doing.

Some of y'all suggested various brands, and to look in the Graingers catalog. Somehow I wasn't able to find anything suitable in that catalog so either I looked in the wrong place ..or...?

A solenoid is interesting because you can control it with a simple circuit such as a keyswitch. But I got to thinking, and the solenoids require a constant current to keep the contacts closed. The one I have now requires 1A continuous to keep the contacts closed, and others required even more.

I got an interesting idea from Lawrence (the guy who sold me the bike). He talked about manual disconnects, and that some exist which can work with a cable. I can imagine a lever on the handlebar that operates a cable that operates a manual disconnect. Unfortunately I couldn't find anything like that either. But thinking about manual disconnects got me to this: Switch, Battery Disconnect, Albright ED250B At Cloud Electric they have this: Switch Power Cutoff - Heavy Duty 5000 Amp ... which also looks interesting, but I went with the Albright switch instead for some reason. Maybe because of the big red button.

It's a heavy duty switch that's got the right ratings for my purpose. Plus it should work as an emergency disconnect in case the controller goes coocoo. Just push the big red button. Power machinery should always have a big red button, right?

I had one time built a manual disconnect with a pair of anderson connectors. One of the anderson's has a loop while the other has two tails. You install this inline in cable. To disconnect the circuit simply yank on the loop to pull the anderson connector. It makes sense in theory, but the one I built is really difficult to pull out. It's also pretty darn large and I didn't see a way to fit it into the bike (space is tight).


echuckj5's picture


dang, welded one shut. Hope the throttle was'nt on. The only reason, unless one has to have the latest and greatest, to use a solenoid activated switch, is, for safety. 60 volts is dangerous to me. When contacters weld with high voltages, you don't want to touch the switch if something goes wrong. Normally, a fuse would blow if there was a problem. But,

For newbies

Manuel, or solenoid, the contacts can weld. They say switching speed is important. Ya, when that switch is powering the equipment. That is what fries the contacts over time. Or, a short circuit, can fry a contact, (contactor) and we hope the fuse blows. What if the throttle sticks, a fet in the contoller shorts. Lot's of ifs. We, in electric vehicles, turn the switch, then power the equipment with our throttle. The switches, normally are rated to handle the switching currents. On electric vehicles, the only current flowing, unless the throttle is stuck on, is the current that powers the caps in the controller. Soooo

I would probably use a solenoid at 60 volts, and, a red handled disconnect. We just run too many amps, imo, Switches are free, just visit my Dad, just joking.

It is a problem, those switches are'nt cheap. If I could only use one, a manuel disconnect would be the safest.

chuckie, getting----real-----close--to---halloween


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