procedure for replacing bearings in a 5 hp motor

I think that I will try replacing bearings in a 5 hp single phase motor. Weight about 100 lbs. My plan is as follows:

0) test the motor first to see if it runs at all.

1) hold the motor vertically by screwing the base to a wooden board etc. Rotor points up.

2) remove top end bell

3) gently pull out the rotor

4) remove end bells and somehow or other pull bearings.

5) insert new bearings into end bells

6) lay the back end bell on the table

7) out the middle part on

8) insert the rotor gently

9) put the top end bell on, screw everything together

i
Reply to
Ignoramus6689
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Dress the points on the starter plate, clean everything well. rest the new bearings on light bulbs to heat em up and swell them, work fast before they shrink. Put some witness marks between the ends and the center so everything goes back together the same way.

Reply to
bamboo

No need to expand the bearings on the Baldor 5HP SF. They press only lightly into the bells, and slide over the shafts with some clearance.

LLoyd

Reply to
Lloyd E. Sponenburgh

The starter switch is in the end opposite the shaft on my motor. Take some particular care to remove that bell without harming the centrifugal switch affair. It's delicate, and a little tricky to get all back together if you futz the disassembly.

I'd do the operation shaft-down, if I were doing it. I'm not sure what "rotor up" means, anyway, since the rotor is inside the motor and occupies pretty much the full length. Did you mean "shaft up"? If so, I'd recommend starting shaft-down.

LLoyd

Reply to
Lloyd E. Sponenburgh

???

thanks, good idea.

Another great idea, thanks.

i
Reply to
Ignoramus6689

Is the press so easy that I can simply pull them out with my bare fingers? Or should I expect to need some tools?

Thanks!

i
Reply to
Ignoramus6689

Yes, I meant shaft down. So, you would suggest to mount it shaft down,, and to gently remove the back (now opinting upwards) end bell. Right?

If so, how should Iremove end bell, just pry it with a screwdriver?

i
Reply to
Ignoramus6689

The points are the electrical contacts in/on the starter plate that dis-engage the start windings on speed. If the motor has been around long enough to wear out a set of bearings these usually need to be cleaned. I pull sone 400grit silicon carbide paper through a few times followed by some newsprint paper.

Reply to
bamboo

and watch bottom end bell, and rotor hit the floor when you remove the bolts.

Not likely.

No problem there.

Proper way is

Throw on workbench loose so you can turn it to get to everything.

Put witness marks on each end plate and motor housing.

Mark down, photograph or otherwise memorize the wiring on the power connector board.

Remove wire connections from top side of board.

Remove bolts which holds end bells (hint the bolts go all the way through motor).

Use punch, chisel, or best is a beater screw driver to loosen back end bell (opposite shaft).

Carefully pull end bell off (might need some persuasion with a soft hammer).

Memorize wiring connections to back of board in some way and remove the ones needed to get end bell free from field windings.

Either use above method to remove front end bell or alternatively use a soft hammer to drive rotor and front bell out of field winding and then remove end bell from rotor in some way.

Replace bearings and reassemble in reverse order.

You might also double check that there are no screws near the bearing portion of the end bells. It's not likely in a motor that size but larger motors will often have bearing retainer plates inside the bells which need to be loosened before removal of rotor or you risk breaking them.

Wayne Cook Shamrock, TX

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Reply to
Wayne Cook

thanks... I will save your post and print it out...

i
Reply to
Ignoramus6689

It's good that you're planning this job way ahead. Having done a few

3phase motors in situ awhile back, I wanted to see if maybe you could save a step, for reasons I'll explain when we get there. This worked for me for on 3 phase motors, but I can't see if that different for a single phase 5hp motor. Mount the motor on something so that the output shaft end is down. Remove the bolts and carefully lift the end up and away. With your hands or a hoist, raise the rotor straight up and out using whatever method of attachment works for you. When you go to replace the lower bearings you may have to reach in, but for a big motor it's no big deal. When that one is done, lower the rotor back in carefully. The reason is that for some reason it's a lot easier to get the shaft slid into the bearing than the end plate on with the rotor resting in the stator from vertical. Being vertical, as you imagine, is a little harder, but trying to move it sideways is a whole lot easier in order to get it to line up. I could never handle holding up the rotor while sliding in and not hurting my back or something. Of course, having a cherry picker or forklift doing the heavy lifting makes things a whole lot easier!
Reply to
carl mciver

Thanks, I saved your post. I do have a forklift right at this moment.

i
Reply to
Ignoramus6689

I drilled a 1" hole in the top of one of my work benches just for doing motor work. Makes life much less exciting, and now also acts as a place to place my bench block for driving out roll pins and such.

Gunner

If you are going to use that phrase then you should use the full phrase of "Fuck Off and Die and Rot In A Ditch and Get Eaten By Maggots and Pissed On and Shit On By a Dysenteric Elephant (but not necessarily in that order)."

Crash Street Kidd

Reply to
Gunner

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