I’ve recently refurbished a Poitras 4800 8” jointer. Today I installed a new motor. I chose to install a single phase 240V, TEFC Leeson. To align the pulleys the motor needs to sit far into the cabinet so only ½” of clearance exists between the side of the cabinet and the fan cover. I’ve looked at other motors and the dimensions from end to end vary by only 3/8”. I’ve checked 3 phase motors as well, (assuming this machine originally had a 3 phase motor), and their dimensions are the same as the single phase. Having read that the clearance between the fan enclosure and obstructions needs to be a minimum of ½ the shaft height, which in the case of a 145T frame would be 1 ¾”, will the ½” clearance be sufficient to cool the motor? It’s in a one man workshop and likely wouldn’t get use for extended periods of time, (though I’d hate to overheat the windings and burn out the motor, it cost $600CAD!). Any thoughts would be greatly appreciated before I resort to cutting the cabinet and installing a screened grill as a last resort.
Thanks, Mike
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For a jointer I would not be worried, the motor will run idle between boards and likely will be used for short periods, from 5 to 30 minutes at a time using only a fraction of its full width. What is the duty factor ? At this price it is likely a high factor, ‘’ E ‘’ or above. You could also drill the cabinet ?
Thanks. The motor is rated 'continuous service'.
I was thinking about drilling holes as well. I imagine I could also reach in and feel how much air is moving across the surface of the motor as well.
Do reach in after disconnecting power after a good run, it will be a better assessment than trying things at this stage, my guess is that it will be lukewarm and it will be just fine as is.
I think what has been said above is correct. Probably no concerns. However, can you elaborate a bit on why the motor has to be mounted "far into the cabinet so only ½” of clearance exists"?
I've attached a picture. The pulley is pushed as close to the motor as possible on the shaft. The pulley on the cutter cannot be adjusted. That leaves me with about 1/2" between the rear of the motor, (fan intake), and the side of the cabinet.
Run it open for a few minutes and see how hot it gets. Put the cover on and repeat. If there is not a noticeable diff you're probly good.
I see. It is the end opposite the pulley that you are concerned about. I agree. I think it will be OK, but test it and see how warm it gets. If it gets hot, consider leaving the cover off as we see it in the photo. This may be enough to provide cooling air. If it does prove to be sufficient, consider replacing the existing cover with a louvered one. If not, I wonder if it is possible to install a small set of fan blades along with the pulley. Wouldn't take much.
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