My Taig is powered by a 110V 1Ph 1750 rpm 1/4 HP induction motor or garage
sale provenance. My concern is that with use it gets too hot to touch.

I noticed that it was quite warm when I hooked it up first around February.
I have used the Taig for brief periods only until now when the heating
became quite noticeable.

I run a test today:

1) I run my drill press (3/4HP) for 5 minutes. In an ambient temp of the
garage of 27.5C the motor heated up from that to 37.0C.
2) I run the Taig motor without the belt for 5 min. The ambient temp by
then was 28.5C and the motor reached 39.1C
3) I repeated the run with the belt and a chuck on the spindle - no other
resistance. Unfortunately by then the ambient temp was 32.2C and the motor
started at 34.2C. After 5 minutes the temp was 46.1C.
4) I repeated the run with the drill press (ambient 30.9C, went from 31.1 to
40.4C).

The temperatures were measured by an IR thermometer.
There was a gradient of temperature in both motors: The front of the Taig
motor was considerably warmer than the back, the reverse was true of the
drill press motor.
The increased temperature was confined to the housing - the shaft and the
pulley on it were quite cool (almost 10C cooler).
There were no unusual noises or smells, no evidence of sparking.
The motor runs smoothly and quietly.
The pulley/belt alignment is good as judged by conventional methods.

Questions:

1) Is such degree of heating abnormal? I have never encountered a motor that
heats up this much so I assume the answer is yes.
2) What is the likely cause? My first thoughts was "bearings" but why would
the housing be hotter than the shaft? Superficially there is nothing to
suggest that the bearings are at fault.

Thanks,

--
Michael Koblic
Campbell River, BC