Start with an a/c compressor to give you the stable crankshaft. Those elec-magnetic clutches run only about .008-.014" clearance, so there is an important shim setting under the pressure plate (on the crankshaft where it comes thru the pulley carrier bearing. You will need to find a cog pulley large enough to fit over the original a/c belt. You CANNOT cantilever the load on that center idler bearing in the clutch package. You will turn the outside of the plate blue (been there, tried that). Some of the small cars have smaller pulley OD, so you might be able to find the combination.
I would try to find a 10P type (has five cylinders running lengthwise) with pistons on a swash plate. Take out the pistons (they just slide off the swash plate as you slide the shaft out), open up the side of the case just inboard of the rear bearing. Put your smaller cog pulley in the opened case and take the drive from the swash shaft to your work. You may need to put sealed bearings on each end, if it is not so equipped.
You could try putting power into the small pulley and going to your work from the larger outer pulley but that could multiply the load against the clutch....might smoke it? I would probably do my speed control off-board, so to speak. This would prevent clutch slip from creating speed variance within your time controlled operation.
This gets you a very stable elec-mag clutch drive that can be run through a fog light relay and small 12v power source. You can put a spring loaded idler in the power transmission pulleys, with a microswitch that gets triggered if load deflects a belt too far. The switch takes the relay control power to ground,
popping an inline fuse and causing the relay to shut off and release the clutch.
....hope I am understanding what youre trying to do.
