24 VS 12 volt solenoids

[Zekester]

Help me out here, I'm told if you want to convert a 12 volt 8274 to 24 volts, you change motors and solenoids....wouldn't the solenoids be running at half the amperage when on 24 volts? Can't a 12 volt solenoid easily be able to take the load?

what am I missing here?

 

[Zekester]

no comments?

 

[denis]

I'm not an electrician but here are my $0.02
I don't think you want to put 24V on the coils of 12V solenoids, they might burn quickly unless you put a resistor in series to drop the voltage. I don't think the contacts side really care about 12V or 24V.
The solenoids work in pairs, so I guess if you just wire each pair in series rather than in parallel on the coil sides you should be good to go as long as each pair is homegenous resistance-wise.

 

[lowenbrau]

You actually only need to change two of the four. They need to change because the coil in a 12V relay melts down on 24V. The contacts can take the 24V, no problem.

 

[lowenbrau]

Denis beat me to it. I think the only reason you have to swap two relays is because the 12 ones have one terminal connected to their chassis. In a 24V setup they are run in series and the 2 replacement relays are isolated from their frame.

 

[Towpack]

what am I missing here?

A physics lesson.

Running anything at double it's rated voltage,be it a solenoid,motor bulb etc. will as near as damn it double the current going through it and burn it out.

True,a 24v rated solenoid will draw half the current of a 12v because it has a higher resistance.



I = V/R etc..etc...

 

[maximBJ70]

so with the boys that are running 12v 8274's on your 24v trucks (yes I know the risks!!!..and your welcome to respond with "my buddy did this..." to save your own butt ;p ) did anyone try just rewiring the solenoids to run in series, yet leave the 12v motor as is? I'm lugging through the problems with this in my head right now.

 

[crushers]

nah, i just bolted the 12V winch up and wired it to the 24V battery...
12V solenoids, 12V motor and away i went...
what is it now, 2 years, 3 years 4??? more? no issues at all, very fast, very strong, long hard pulls, short pulls, free wheeling etc etc...

then, maybe, i just have a huge horse shoe up my....

 

[george_tlc]

A 24V 8274 uses 12V solenoids. I converted my 24V 8274 to 12V a few years ago, and found that the solenoids are 12V. The ONLY difference between a 24V 8274 and a 12V 8274 (other than 24V vs 12V motor) is how the 12V solenoids are wired AND the type of solenoid.

On the 24V winch the 2 top solenoids have their ground connection through the small studs AND through their case (to the metal bracket and hence to ground). The 2 bottom solenoids are DIFFERENT than the 2 top solenoids and their cases are electrically isolated. This allows the a top/bottom pair of solenoids to be series connected for 24V operation.

On the 12V winch all 4 solenoids have their connection through the small studs AND through their case. This means you can easily rewire the solenoids of a 24V 8274 winch for 12V operation since you can ground the bottom 2 solenoids via their studs.

BUT converting a 12V 8274 winch for 24V operation is trickier, the bottom 2 solenoids need their cases to be electrically isolated from the bracket they mount to - otherwise you will have big problems. So, one choice is to purchase 2 new solenoids that have isolated cases (as per the 12V bottom solenoids of the 24V winch) or you need to put insulation between the bottom 2 solenoids and the bracket and use nylon bolt/nuts to attach them to the bracket to isolate the cases from the bracket.

See my writeup on converting a patrol from 24V to 12V and you'll find the info on the 8274 conversion. In your case you are converting from 12V to 24V versus what I did, but the info is relevant.

Essentially on the 24V winch each pair of 12V solenoid coils are wired in series versus in parallel for the 12V winch.

MQ 24V to 12V retrofit

cheers,
george.

 

[Stone]

Ohm's Law...

 

[BJ-44]

My experience is that a 12v Solenoid/relay will work fine in a 24v system but it shortens the life of the relay. With a lot of the 12/24 volt military systems 12v relays get swapped into 24v slots and they operate fine but are usually hotter than normal which is probably why they wear out quicker.

 

[george_tlc]

Ok - I'll refer you again to Post #9.

The 8274 24V winch USE 12V SOLENOIDS AS FACTORY INSTALLED UNITS. There are 4 solenoids with each pair's coils wired in SERIES hence 12V + 12V = 24V so they are running IN SPEC. The 8274 12V winch uses 12V solenoids with each coil running at 12V.

To convert a 12V winch to 24V operation the only thing you need to do to the solenoid pack is to rewire the coil feeds to have each appropriate pair in series (so each coil still only sees 12V) AND insulate/isolate the bottom 2 solenoids from the bracket. You can then replace the 12V motor with a 24V motor.

cheers,
george.

 

[maximBJ70]

You guys are great. Thanks again Wayne, thanks George. My stomach is now well settled on this subject. Away we go!!!

 

[ForealBoreal]

my problems have been solved