What am I missing

AAE

Learner
I'm reinstalling the motor on my compressor. But, I can't get the shaft to stop free spinning in the flywheel. There's a key slot in the shaft but no key. But, there are set screws. I've tried screwing a set screw into the slot but it still freewheels. What am I missing?
 
Without seeing what you are looking at, my guess would be the key goes into the slot and the set screws tighten against the key.
Get your model number for the compressor and do a search for parts. This will confirm a key is used and the part number or size of the key, so you can get a replacement.
 
all have a key slot . most likely as stated the key is in the old shaft. if the old had a key and the new shaft doesn't i'm not sure what you have. never seen one with only a set screw. pics ?
 
it may be one that is cone shaped. the one on mine has a weird pully system . same motor or new one?
 
it may be one that is cone shaped. the one on mine has a weird pully system . same motor or new one?

That's a possibility. If the arbor shaft is tappered, then it's a press fit and the set screw holds it in place. AAE could verify this by looking at the old motors shaft to see if the shaft is tappered, and if there is a score mark from the set screw on the arbor shaft. Most likely there is one flat spot on the arbor shaft for the set screw to seat to.
 
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all have a key slot . most likely as stated the key is in the old shaft. if the old had a key and the new shaft doesn't i'm not sure what you have. never seen one with only a set screw. pics ?

It's also a possibility that the old key sheared itself off and half of it is still stuck in the arbor shaft.
 
PXL_20220625_142717025.jpg
 
I'd like to see where the set screws are located. ( are they on the pulley) That shaft has definitely been milled for a key way. This can be verified by looking thru the pulley and see if it has a slot. I would also check the length of the new motors arbor shaft to the old arbor shaft length. The new motor arbor looks too long.
 
Okay I see what's going on. That collor with the set screws is to position the arbor shaft on the pulley. You have the arbor shaft of the motor pushed too far in.

If it was me, I would pull the motor and look at the existing pulley to see if it has a slot for an key. If it does have a slot and the key is not there, then it fell out during disassembly.
 
The marks in the first pic stop at a raised area to keep the collar from going past it. The apex of the slot is 3/4 in from the raised area. The set screw is 5/8 from the outside edge of the collar. Doesn't seem like they would meet up any way. Yes, there is a slot in the collar too. I've looked around the floor and see no sign of a key.
PXL_20220625_145836751.jpgPXL_20220625_145842916.jpg
 
Motor pulley was changed to a non keyed hub,Motor was changed to a keyed shaft,Maybe the comp pump is trying to lock up,pulley never had a keyway and just used the set screws. Lot of 'options' here .
Pull the pulley off and see if it originally had 2 set screw 'marks' elsewhere on the motor shaft.
Tightening the set screws INTO the motor KEYWAY is A VERY BAD THING. You likely with have a hard time removing the pulley as you created an interference fit by gouging the shaft and unfortunatly,the pulley is up against the motor bellhousing and only one way to get off. If you try to pry the pulley using the motor as a pry block, be careful to not damage the motor bearings or endbell.
Your at a point where you need to remove the whole motor/pulley assembly and really find out the problem and room to work in.
 
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