I toasted my electric motor on my 5 hp air compressor last winter and have been looking around C/L and E/B for either parts or a new/ / different one.. What I've been seeing is a lot of the new junk which is both noisy and poor quality. A comparable one is ~$6-700 and I'm too cheap to spend that much coin on one & prefer my old quiet oil filled pump type so I searched high and low for a new motor to replace the old blown one. Of course the old one is NLA! So the compressor sat in the back of the shop awaiting attention like my other projects.. So I looked around for motors and after investigating and finding many over-priced options it was Harbor Freight to the rescue again!! I got a 3 hp 3600 RPM NEMA 56 frame for ~$160.00. The motor and shaft were correct but the frame was nowhere close to what I needed to have due to the design of the tank & mounting frame. The frame was a special pivot mount.. I transferred the mount from the old motor to the new one..
Not a natural thing to do to tear the frame off a brand new motor was a difficult thing bring myself to do.. **If it didn't work I was out the $$$ and still no compressor..
Ahhh.. What the heck!! Over to the drill press to remove the welds as well as I could.. So after tearing the welds up I broke out the air chisels to remove the rest of the way/ break the rest of the welds.. (2nd picture above).. The next thing to do was to figure out how to make the electronics work.. Of course the location I need to weld the bracket is not the place that I have any clearance to use the included wiring and circuit breaker hardware. The end cover was out of position so in order to get the vent in the correct place I had to rotate the switch (and splice in a few inches of wire on the stationary coils) to get them close to the correct place. The new motor laid in pieces on the bench while I figured out how to accomplish this.. (scratched my head)
I had to fab up something to work that would not interfere with the air pump as the old one was on the pump side and would not have fit too well. So 'handy box' to the rescue here. I got out the green lee hole punch to put a hole in the motor's end cover (I aligned the hole so I could screw the box onto the motor end cap as well) and popped it together. Next came the circuit breaker button.. Using a blank box cover I popped a hole in and then located & drilled the hold-down screws and put them in place. Then the button was installed and the power wire was spliced in. I also had a 1.5" hole in the side of the motor that needed to be covered so I tore up the old (new) wiring box and installed a hunk-o-screen to hopefully keep the critters out while giving it another ventilation hole.
Next was to finish wiring the thing up. Of course I wanted the shaft to rotate CCW so I wired it to spin CCW per the instructions.. Nope.. The rotation is CCW from the back side of the (starter switch) of the motor. I rewired it CW and things worked great & even turned the way I wanted them to!!. I reassembled all the covers and the thing lives and breathes again!!
Edited by WNYTractorTinkerer, June 01, 2015 - 08:03 AM.