Electric Clutch

[DBXFX]

I've read that it may be possible to use an electric clutch from a car's ac compressor in a go kart

Supposedly, it does not engage until you gie it 2-3 amps from a battery (12volt i assume).

I plan on using a car battery anyways in my setup and i think that this 2 wire setup would be easier than rigging up the belt clutch setup..

They have to be pretty heavy duty due to the fact that they are used in cars and trucks. I guess it works by the electromagnetic field which to engage it pulls weights/magnets centrifically to the outer drum in the same way that a centrifugal clutch does.

Anyone have thoughts or experience with these?

 

[1992suburban]

haha get one off a PTO from riding lawnmower..

my husqvarna has an electric PTO

 

[sideways]

lol i was actually going to ask if anyone has ever used an ac clutch on here earlyer today!

the only bad thing i can think of would be that they would just sudenly engage, just like dropping the clutch in a car, i think they would work though

Hayden

 

[DBXFX]

Yea i was just wondering because my buddy has an old scrap s10 that i think has ac in it hopefully.

I dont think that they quickly engage as that would cause a gas engine to sputter/ stall at idle possibly. I read that they kind of slip by themselves as the magnetic field builds up. I think im going to give this a try if hes does indeed have ac.

 

[kazkepox]

it sounds cool, if you get it make a thread about it and pics!

 

[lemegacool]

read on this but i think these clutches are very sensitive to voltage variations and can burn out easily if the voltage applied tho them is too high...

 

[modelengineer]

I wouldn't do it. These clutches don't slip, they're just on or off. I imagine they can't handle much power either.

 

[DBXFX]

I wouldn't do it. These clutches don't slip, they're just on or off. I imagine they can't handle much power either.

power as in torque?

im sure they can handle much more rpm as they work off a car. I think the clutch's grip vs torque would be the only thing. would more current help though?

 

[anderkart]

You might be able to rig up some sort of rheostat that would gradually increase the clutches pull-in voltage (and hopefully its grip factor) to finally reach full lockup at 12 volts.

I have no idea how much extra voltage one of these would accept before burning up the electromagnet coil, but it does makes sense that excessive voltage probably would make the clutch lock in tighter. A cars charging system usualy runs around 14 volts so you'd be safe to that point for sure. I doubt you'll find anyone else thats tried this with higher DC voltages so you'd probably have to install two 12 volt batteries (or meyby one 12v. and a 6v.) in series to experiment with this concept.

Below is a quote from a very knowledgeable DIY member on this subject:

from this thread: http://www.diygokarts.com/vb/showthread.php?t=4821&highlight=compressor+clutch

A modern automotive air conditioning compressor draws about 2HP continuous with an initial requirement of 3HP when the clutch closes. Also, these compressors are designed with variable vanes to minimize the "thump" when the clutch is electrically activated.

Older air automotive air conditioning compressors could require as much as 4HP and the clutch was designed to take 5HP, because engagement was real harsh on both components.

Mower PTO clutches as they are called, generally rated to 5HP even if the engine is much larger, because it doesn't take 5HP to spin a 20", 22" or 24" blade. Remember that the larger mower decks have more than one blade, so the blades themselves on those decks are smaller than even a 5 HP push mower (typically 26-34" depending on the mower).

The PTO clutch on farm tractors is another animal altogether, and really just a one-way clutch used to avoid the situation where you push the clutch in on the tractor to stop movement and the momentum of the mower blades (or other implement) continuing to turn the PTO shaft, keeping the transmission bits turning and the tractor moving. It works much the same way as a ratchet wrench works, and if you rotate them by hand you'll even hear the clicking.

I was thinking about this for my son's riding kart (see "backbone kart" thread), because with a 4-5HP electric motor, this clutch might be a perfect fit - and allow me to spin the motor up a little bit before engaging the clutch.

 

[02mx-5]

why would you put a clutch on an electric motor? electric motors arent spinning until you give the motor power. therefore no clutch is needed. The reason gas engines use them is because they are constantly spinning. If they didnt have them the kart or bike would just go without giving itgas. Maybe im missing the point of your project.

 

[anderkart]

Your right but a centrifugal type clutch used on an electric powered vehicle could be used to allow the motor to gain some RPM (under no load) and then fully lock in at the clutches stall speed. This should give better initial acceleration and could also end up drawing less amperage during take offs.

ps: the OP of this thread never mentioned using an electric motor, but frederic's quote did.

 

[DBXFX]

why would you put a clutch on an electric motor? electric motors arent spinning until you give the motor power. therefore no clutch is needed. The reason gas engines use them is because they are constantly spinning. If they didnt have them the kart or bike would just go without giving itgas. Maybe im missing the point of your project.

Yea, i meant putting an electric powered clutch on a gas engine.

anyone know where i could maybe get a heavy duty rheostat/potentiometer?

I just had the idea to that if using an electric clutch, to hook up a clutch pedal with a rheostat as the hinge. that would make a fully controllable by pedal clutch i think

edit:: i think an automotive dimmer would work pretty good.

 

[anderkart]

I'm still not sure this whole concept will actualy work or not, but I like your clutch pedal and automotive dimmer ideas. I searched around for a pivot arm type, DC rheostat/potentiometer that would handle the amperage draw and didnt find much that was reasonably priced.

To experiment without spending any money... If your buddy's S10 has the old (pull-knob) style light switch with a built in spring type dash light dimmer switch, you might be able to attach an arm to its shaft and wire into to its rheostat function for free.

 

[DBXFX]

I'm still not sure this whole concept will actualy work or not, but I like your clutch pedal and automotive dimmer ideas. I searched around for a pivot arm type, DC rheostat/potentiometer that would handle the amperage draw and didnt find much that was reasonably priced.

To experiment without spending any money... If your buddy's S10 has the old (pull-knob) style light switch with a built in spring type dash light dimmer switch, you might be able to attach an arm to its shaft and wire into to its rheostat function for free.

yea it does in fact! as soon as i get the good to go on that truck i should be able to start testing things. its seems possible to make it work, i just hope i dont fry the thing

 

[anderkart]

Yeah it'll be interesting to hear how this all works out.

 

[02mx-5]

Ohh ok. the OP mentioned using a car battery so i thought it was an electric project. Now that i see what your doing it sounds very interesting. Id love to see it when its done.