Motor frames

[spro]

The current list of NEMA frames do not include many that were in use 100 years ago. That makes sense. Then 80 or sixty. Then it gets interesting. I accept that motor tech has evolved into greater efficiency at lighter weight. I know the fields' insulation can sustain higher temperatures than before. There is something else going on with the old motors and mill heads. I know they are heavy pigs and I wouldn't want to lug them around or replace them overhead. This stuff already happened. There is a stability by shear mass where 1/2 hp is more by kinetic energy. There are motor frames and many were custom to the particular machine. That machine maker didn't start making motors as a sideline, they made adaptions to it. I believe this became a frame number. You have the guts of the motor between bell ends of an obsolete frame and it is either Fairbanks Morse, General Electric or U.S. Motors at that time. Of course I don't know a smidgeon of what has already been posted somewhere else.
Why? Because the arrangement of these things depend on long shafts. That means larger diameter shaft and bearings to support. That means a heavier case to support large bearings. These made the newer. The innards are from a motor manufacturer and code for longer shaft or whatever. Some, like the Fray, have a drum switch built inside the end bell/case. There are unique fixtures for mounting them and had an obsolete frame. I think another motor's field section fits right in.

[warmstrong1955]

Sometimes....when you design things...a standard off the shelf motor, or whatever it is, won't do it. So.... The OEM's hook up with the guys who build the motors, or whatever other components, and make a deal. Long shafts....weird notso standard frames...whatever. They do what they have to to fit the envelope.

Standards be damned...can't avoid it.

Sometimes.... they make a deal....and design things....just so they can be the exclusive supplier for the parts & pieces and components....should the dreaded need for a replacement parts arise.

Standards be damned....on purpose.

Been there....a few times....I know....
Like Bruce said....that's just the way it is.....


Bill

[spro]

"Fit the envelope", thanks. It is to know back those days and understand. There are some here who experienced those days. Maybe they don't want to look back for good reasons. Cussed setting up the head but did the work.
Appreciation is one thing. There are probably some who grit their teeth thinking another would go this road again.

[pete]

Yep your both 100% correct. And not only is there all those obsolete frame sizes and equipment specific motors and frames. But today there's at least 3 recognised yet different frame and motor standards in common use. There's both imperial and metric, and then the Chinese and possibly along with Taiwan have there very own separate motor and frame size standards they've developed. I think I recall it being listed as an Asian frame standard. Although for high cost equipment built for retail or industrial sales in either Europe or North America, my guess is the dealers could specify a more common imperial or metric frame and get it if the volume was large enough.

As long as the bearings are still available, then almost any motor obsolete or not could probably be rebuilt / rewound to new condition. Unfortunately today it's seldom even close to being cost effective. And even more so for anything that's 3 phase. 50 years ago I think it was much more usual to have those heavy weight motors rebuilt and rewound at a far cheaper cost in comparison to what we'd pay today verses the cost of buying a brand new motor. And 50 or more years ago I doubt I could pick up one of those heavily over built 3 hp motors. Yet it's not much problem for me with my 3 hp Asian built motor on my mill.

Pete

[Comstock-Friend]

I just worked with Leeson to come up with a line of motors with no shaft extension. The motor shaft is bored 0.500" ID x 1.5" deep with a 0.125" keyway broached. There is a 1.5" reference ring and an SAE 4 bolt pump mount bolting face. Allows me to bolt a hydraulic pump directly to the motor, saving pump/motor adapter, coupling, etc. and saves about 5 inches of assembled length on pump/motor assemblies of 1.5, 3 and 5 HP. Hope to be ordering hundreds, but certainly not thousands.

John

[redneckalbertan]

I just worked with Leeson to come up with a line of motors with no shaft extension. The motor shaft is bored 0.500" ID x 1.5" deep with a 0.125" keyway broached. There is a 1.5" reference ring and an SAE 4 bolt pump mount bolting face. Allows me to bolt a hydraulic pump directly to the motor, saving pump/motor adapter, coupling, etc. and saves about 5 inches of assembled length on pump/motor assemblies of 1.5, 3 and 5 HP. Hope to be ordering hundreds, but certainly not thousands.

John

Often wondered why this had not been done. It makes so much sence in my mind. But I though of it in reverse with the accessory being bored and the motor or engine retaining its shaft.