I posted about this motor a couple of days ago, and wanted to follow up in
another direction. The motor in question is 1-hp Craftsman motor from a
table saw and is about 45 years old. After rewiring it for 220 volt
service, it started a few times and now doesn't want to. When completely
cold, it starts fine, but after running for a few minutes (no load) it warms
up a bit and then will not restart. When power is applied, it rotates
This motor is labelled "1 Horsepower Capacitor Motor" and also "Ball
Bearing". I assume that the bearings are pretty good, because it takes 70
seconds to spin to a stop after power is turned removed (yeah, I timed it).
More importantly, it apparently has a capacitor for starting, but I don't
see it anywhere. There is no external capacitor housing or cover like I'm
used to seeing on more modern motors. Could it be inside the frame? I
hesitate to take it apart just to see. Also, I assume that this a brushless
motor since it's gone nearly a half century without replacements.
Can anyone tell me more about this motor and/or direct me to a site with
such information? TIA.
I have a similar Craftsman motor, about 48 years old. The capacitor is in
the base. Sounds like a problem in the starting circuit, might try cleaning
the starting switch. I THINK these motors were made by Emerson Electric?
Mine is a model 115.-----, the 115 tells who the manufacture was if I would
take the time to check the Sears manufacture code index.
Yeah I think that is Emerson.
Again, there are motor shops that work on such things, take it in and
have them look at it. Mine is doing business now as
http://www.emotorstore.com but I've been going to their physical store
since I was a kid, with dad. Bring in the motor, and walk out with what
That it rotates backwards, suggests you have the windings wrong, and
need to reverse one of the wires.
I don't know which one, of course.
I've only a 3/4 hp 115 vac motor, so I can't help there.
Sorry to change the subject slightly, but still on Crapsman's motor.
I have been planning to replace my 1HP motor and I just could not figure which
motor to buy or who is really telling the truth, especially "Farm Duty", is this
electrical motor more heavy duty than commercial industrial motor?
Further, almost every domestic household appliances, electrical motor advertize
something like "9 Peak HP" or 3HP when it's really a fractional HP motor when
using NEMA standard?
Look at the website which I'll leave below, they have a wealth of
information on how to select the right replacement motor, and FAQ's and
more information. Great read.
Duty is rated as service factor, where 1.0 = published HP. A service
factor more than 1 means it can deliver more than the rated HP.
Can you say "marketing forces"? Again, look at the emotorstore.com
site, they have a lot of info that explains what you need to look for in
a motor, and what the terms mean.
Good site lot of info. But it did not explain "Farm Duty"?
I check GE 1-1/2hp Totally Enclosed Fan Cooled", price as low as $147 and over
$250. Grizzley selling "same" Emerson's assembled in US or imported for the
I can understand "marketing forces", it's like telling 1/2 truth or comparing
apple with pear.
By the way if I decided to replace the motor I will get it from them. Thanks
Look under service factor. I don't know the term "farm duty" either.
GE are like top of the line motors, I've never had a problem with them.
I remember a summer job in building maintenance, where the building
engineer sent me over there to pick up a 7.5hp GE motor, cause he was
tired of screwing with a re-build or other motor problems.
Good folks, I've been dealing with them for 30 years. Of course, being
local, I can just take the old motor in, and say "one of these, please",
which is what I did a couple of winters ago, with my furnace motor.
Farm duty seems to be 1.15 service factor, 300% and greater starting
torque for hard-to-start applications, totally enclosed and gasketed.
Probably not needed at all for a TS, which doesn't start under load.
Hey, I use to work for GE Apparatus Services. We rewind all kind of motors, I
mean the real big (HP) one, the smaller one we subcontract it to smaller shops.
We also repairs industrial gas Turbines and power generation stuff all over the
They seem rather honest and tell you as it is and not blown it out of proportion
like my ShopVac "6.3 PEAK HP". I could barely lift a real NEMA "3HP" -:)
PS:Happy New year to you and thanks to your valuable contribution here to people
who need advice.
Actually, no. In the 50's Craftsman was actually good, in the way of
tools. Not great but very good.
That 50 year old tools are still being used, and maintained, speaks to
that. I expect to get several more decades out of my TS.
Yes, nowadays the brand may be crap, but these are from its heyday.
Nope. No cap in the base. It's got to be inside the main motor case. This
motor has forged, rounded end pieces with no obvious corners or bulges to
hide anything. I agree with the idea that maybe the old cap couldn't handle
the higher voltage. The next step is to open it up, I guess. The reason I
hesistate is because I've had re-alignment problems at times in the past
when trying to reassemble motors. Wish me luck.
Scribe a line across the bell ends and housing before disassembly to prevent
alignment problems. I would also check for loose connections in the start
since the problem is thermally related.
From the Drisilker (emotorstore.com) faq:
FACT: Replace the capacitor when replacing a defective motor. If a
defective capacitor is in the circuit the motor probably will not run,
it will operate as if overloaded. The motor speed will be low, it will
overheat and probably activate the overload protector causing cycling.
So it sounds like it may be the cap, which being old, couldn't take
being switched to 220v. They also have wiring diagrams and a bunch of
other motor tech stuff on their website.
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