Round motors and square motors...
The round motors hung around the longest in the three speed versions, well into the 1970s. To my knowledge, there was never a 3-speed square motor. Three speed belt-drives were in production at least into early 1974 in the 1972 Lady K model that ended at some time in 1974. There may have been a 3-speed Whirlpool longer than that? These three speed versions were somewhat unique in that they were capacitor start motors, with the capacitor encased in a pod on the side of the motor. I believe the majority of the other round motors, at least in the 1960s, were split-phase. There may be exceptions.
Yes indeed, CFZ is correct in that GE, Emerson, and Delco provided round motors, and there were others in the earlier days. Packard? John would know.
The transition from round to square happened around 1970-ish, though I can't quote a time. This may have been gradual. I have a round motor machine from 1969, and have had square motor machines from 1971. In the first half of the 1970s, GE made A LOT of the motors for belt-drives, I'd venture to say almost the majority of them (single and two speed), and can be seen from a mile away as a drab painted monotone gray square motor. These were mostly all split-phase motors. These motors for the most part sucked out loud, and I mean that almost literally because they could be noisier than a Ford F-350 V10 without a muffler. They could make the whole machine vibrate, and any place there was a meeting of two metal surfaces that weren't totally locked down tight, or metal on plastic, the motor would make these seams vibrate. As bearings in the centerpost get some age and wear, it makes the machine almost deafening. There was some capacitor start GE motors in the early 1980s, not many, but these were just as bad as the motors from ten years earlier, at least from what I've seen. I had several in machines in the 1990s and I didn't re-use any of them in my refurbishments. One or two of those got so hot they burned my fingers, when the motor should usually just be comfortably warm.
The square Emerson motors do not have this reputation, and are much less trouble prone, maybe even trouble free? I've tossed many GEs for getting hot as CFZ states, when a new belt was installed because the bearings were wearing in the motor. I don't recall many issues with Emerson square motors other than one which was so worn, the armature broke, and quite suddenly (running), while I was within a foot of the machine making my visual/operational inspection. That was almost a 'change of drawers' moment...
I don't recall ever seeing a Delco square motor, so I think by the late 60s / very early 70s when this transition occurred, Delco was no longer supplying motors to WP?
As to using a round motor in a machine originally equipped with a square, as long as you replace one with the same or more number of speeds, it would fit just fine. The big round motor would probably not fit the original portables (up to 1974 or so) as these are very low to the floor and would have some clearance issues, but otherwise the only thing I would be concerned about is having enough slack in the wiring harness to get the two or three wires (blue and white or blue, white and orange) down under the round motor to make the connections. This is going to take several inches more wire than the shorter square motors with their start switches which allow wiring plug-ins from the side.
Depending on the age of the machine you just got, a square motor may have already replaced a round one, so it would be neat to revert back. Square motors (capacitor start) are still readily available, new, from FSP to replace all single and two speed motors from 1956 or so forward (which I think is pretty cool, however perhaps not totally original).
One thing of note - I have not seen this in print as any policy or procedure from whirlpool, but I'm fairly sure that in the days of the square motors, nearly every large capacity belt-drive I've ever seen had a capacitor start motor, and most all the standard cap models had split phase motors. The split phase motors start a little bit more gently than the abrupt capacitor start versions. I am not sure I'd put an old split phase round motor into a large capacity machine unless I had to - if I had a nice capacitor-start Emerson, I would not hesitate to use it.
Gordon[this post was last edited: 2/12/2013-23:25]
