I have a 2 hp squirrel cage blower kicking my ass. after about 200 hours run time max, motor #1 failed, overload stopped resetting. motor was drawing @ 10 amps, nameplate 11. Motor #2, drawing just under 11 amps, same sheave, same motor. #2 started cycling on overload after two weeks. when I was called, it was drawing 12.6 amps, cycling on OL, windings were chocolate color, checked capacitors, bought smaller sheave, motor draws 12.6 amps even unloaded. Replaced run cap., 12.6 amps. 4.15" sheave or 3.25" full open, 12.6 amps. WTF. Ok, motor is toast, got a new one,put it in.
New motor runs the same, 12.6 amps. Motors all the same- 208/230 single phase. Line voltage is 246.5 with unit off, 244.9 running. Block the return air with cardboard- 12.6 amps. run without belt, 12.6 A. 4.15" sheave, motor loaded as much as I can, 12.6 amps. 3.25" sheave, 12.6 A
Customer has a newbuild 15,000 square foot home with all low voltage lighting. I start trying to shed power to the lights to see if anything changes. My thought was that all those electronics may be somehow altering frequency or changing the incoming power . No help, 12.6 A. This is one of my two residential accounts but all the equipment is commercial. I started questioning the 246.5 applied voltage, but it is within 10% of nameplate. measured 60 hertz, with lighting energized and off.
I am out of options. right now my plan is to take both motors (#2 and #3) to be bench tested at a local electric repair shop.
Any ideas or suggestions would be appreciated. If you made it this far into my long post, thanks.