fun h bridge for winch control

Yup. A fire extinguisher.

When Joerg says *PHUT* ... *LISTEN*

Ed

Cheers! Rich

My Warn winch uses #2 stranded copper from the battery to the relays and then to the motor. The control switch appears to be made up of 3#16 SO cord.

The relays go on the motor (within a few inches of it). The control switch must have a long enough cord so as to allow the operator to take cover in the event the hardware snaps. Actually, my cable is long enough so I can run the control switch to the driver's seat (through an open window) so I can steer while pulling. Water isn't a big deal for the motor and relays. If its clean, it'll dry out. If its full of sediment, you'll have to tear the winch down and clean it.

That's why one always has the owner of the car being towed attack the strap/cable/chain to their own car.

But this is nothing compared to what happens when you winch a really stuck rig out using a nylon tow strap. The tow strap stretches, storing a hell of a lot of energy. Then the hook or clevis (or bumper hitch that some morons attach to) snaps. It'll go right through your windshield.

Steel cables and chains don't stretch as much and consequently don't store as much energy. But they can still whip by pretty quickly. And they don't call the broken strands of a cable 'meat hooks' for nothing.

That's how Warn does it. Picture an H bridge (made of relays) controlling the field. Battery (+) comes in the top of the bridge. At the bottom (where you'd expect (-), the bridge is connected to the motor armature.

controller

winch

whatever

the

this

this:

some

themselves

After

your

is

fet?

The

also

cost

Just the same, i would put some snubbers in there. =20 BTW get a HUGE battery. At 300 A, a 50 Ah battery lasts maybe 10 minutes.

impress

out

stuck

of

morons

store

don't

Actually, the steel cable (or wire rope) will store quite a bit more energy (much higher tension per unit cross section). The nylon strap will smash windows and people pretty good, but wire rope will cut a person in half or even split a car. I have seen the movies, pretty gruesome.

Even chains will store energy (despite common conceptions that they don't). I took out a windshield with a chain once, no fun. Was glad I was wearing sun glasses that day, chain didn't make it through the glass, but glass fragments made it to the back of the truck (a distance of almost 12 ft!)

The safest is synthetic winch cable, as long as it doesn't have a metal hook on the end. We use very overrated hooks so that the cable will fail before the hook. Seems to be the best solution. Biggest issue with synthetic cable is taht you must baby it so it doesn't get damaged.

Once saw a guy try to pull a grader that had slipped on the side of a pile with a bulldozer using a chain. As they started to tighten it, one guy was holding the chain the center to reduce the slack. As I reached for the phone to call 911, the guy leapt over the side of the pile just as the chain tightened and snapped...

Charlie

We modify it slightly in the aviation world,

"Hey, hold my beer and y'all watch THIS one."

Jim

I always though it was:

"Oh God!! We're all going to die!!"

"That's the passenger address system light, not the engine fire light you idiot!"

That's a Far Side cartoon that has to be hanging in every pilot ready room in the country.

Jim