Ok to change from a 3/4 hp to a 1 1/2 hp table saw motor?

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Forum topic by Brian posted 08-13-2014 02:04 PM 2835 views 1 time favorited 14 replies Add to Favorites Watch
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5 posts in 1946 days

08-13-2014 02:04 PM

Topic tags/keywords: 1 12 hp motor table saw rockwell beaver tablesaw


I need help. I read some of your forum and you guys seem pretty decent with informed suggestions.
I want to know if I can switch from a 3/4 hp to a 1 1/2 hp motor on my saw.

I have an old saw, a Rockwell Beaver 3/4 hp 9” table saw, that I am used to and the motor has quit.
I found a 1 1/2 hp Open Drip Proof Electric Motor at Princess Auto on sale for $92.03.

Attributes & Specifications
Horsepower 1-1/2
Full Load Speed 3,450 RPM
Voltage 115/230 V AC
Full Load Current 13/6.5 A
Face C Face flange for direct coupling in applications
Hertz 60
Motor Phase(s) 1
Full Load Torque 2.25 ft-lb
Starting Torque (ft.lbs) 3.61 ft-lb
Insulation Type B
Service Factor 1.15
Shaft Diameter 5/8 in.
Frame Type 56C
Rotation Direction (when facing shaft) Reversible
Totally Enclosed Housing No
Open Drip Proof Housing Yes
Auto Overload Protection No
Manual Overload Protection Yes
Rigid Base Yes
Resiliant Base No

I am in the middle of several projects and need to get back to running this saw.
Thanks for your thoughts.

-- Brian, Belleville

14 replies so far

View Crank50's profile


173 posts in 2139 days

#1 posted 08-13-2014 04:07 PM

That is a pretty strong motor for a 9” blade.
Don’t know if the shaft, bearings, the belt and sheaves (pulleys) would be sized for doubling of the power.
I would rather have a TEFC (totally enclosed fan cooled) motor in a table saw application.

If it were mine, I’d be looking for a TEFC 1HP motor.

View Fred Hargis's profile

Fred Hargis

5838 posts in 3056 days

#2 posted 08-13-2014 05:58 PM

If the RPMs and frame size work, I wouldn’t be afraid to install it. That may be a compressor duty motor, but should still work for what you need. As for the ODP, a lot of cabinet saws come with them….TEFC may be desirable, but not necessary (IMHO). Are you sure there isn’t something simple to fix with the old motor, like a blown cap or stuck switch?

-- Our village hasn't lost it's idiot, he was elected to congress.

View Brian's profile


5 posts in 1946 days

#3 posted 08-13-2014 11:43 PM

The motor will hum without any rotation and the lights in the shop dim. A friend here said it seems like it might be shorting out. I know so little about motors and have no other friends about who are savvy with them. What a blown cap or a stuck switch is or what it looks like, I don’t know. The motor shop said that they saw the motor turn in reverse for a moment indicating that the windings are shorting out.

I am three small projects behind now and I think I’ll buy a 1 hp or the 1 1/2 hp motor. They are one pound different in weight, they run at the same speed and the cost difference is $10.

Thanks a lot for taking the time to help me out. I appreciate it.

-- Brian, Belleville

View poospleasures's profile


836 posts in 3047 days

#4 posted 08-14-2014 12:06 AM

It will work just fine. We changed the 1 HP on my son-in-laws old sears contractor to the 1 3/4 Hp from my craftsman hybrid. Works like a champ for over a year now.

-- I,ve had amnesia for as long as I can remember. Vernon

View OhioMike's profile


85 posts in 2726 days

#5 posted 08-14-2014 12:21 AM

I think the saw will handle the larger motor just fine. However, the shaft on the new motor may be larger and might prevent you from using your old motor pulley.

I agree with others that a TEFC motor would be preferable to an open drip-proof. Still, the old Craftsman table saws all came with ODP motors and they worked fine. You just had to blow them out with compressed air every so often.


View Grandpa's profile


3263 posts in 3238 days

#6 posted 08-14-2014 01:47 AM

Go for it. For only $10 get the big one.

View OldWrangler's profile


731 posts in 2158 days

#7 posted 08-14-2014 02:41 AM

The people in Belize have a saying…..

Big shoes, small shoes
Same price
Give me the big shoes

For $10 difference, go big.

-- I am going to go stand outside so if anyone asks about me, tell them I'M OUTSTANDING!

View Crank50's profile


173 posts in 2139 days

#8 posted 08-14-2014 08:49 PM


I know so little about motors. . What a blown cap or a stuck switch is or what it looks like, I don t know.
- Brian

That hump on the back of the motor is the cap (starting capacitor). It’s job is to tell the motor which direction to run. If the “cap” is bad the motor could display any of the symptoms you describe. A new one usually costs less than $7.00 so even if you buy a new motor, it would be worth while to replace the capacitor on your old one to see if it makes it run. If it does, then you know not to trust that motor shop again, they were trying to rip you off.

The fringe benefit of fixing the old motor is you can always use a spare motor to make a buffing machine, sanding disk, or whatever. Or, sell it on CL.

View WhyMe's profile


1196 posts in 2124 days

#9 posted 08-14-2014 09:10 PM

If the motor hums and lights dim it’s most likely a bad capacitor. If it was a short in the motor the circuit breaker would trip. Replace the cap. If you have a decent multitester you can test the cap.

View Brian's profile


5 posts in 1946 days

#10 posted 08-15-2014 12:58 AM

I’ll go back and purchase a capacitor for the motor and I’ll let you know if the motor runs again.
I’m not quite sure what I hope for here!

I should have done this at the outset, right?

-- Brian, Belleville

View crank49's profile


4032 posts in 3534 days

#11 posted 08-15-2014 03:57 AM

I would have checked this at the start, but, like you said, you did not know.
I have an air compressor motor that quit on me many years ago and I didn’t know the capacitor was the problem.
Be aware there is a centrifugal switch in the end of the motor housing that switches the capacitor into and out of the circuit at start-up. Actually, it connects the capacitor when the motor is stopped. Then, the next time it is started the capacitor is connected and helps the motor start spinning in the right direction. As the motor reaches speed the switch opens up and lets the motor run without the capacitor. Sawdust can get into this switch sometimes and prevent proper operation. It’s a good idea to blow this switch out with compressed air and see if it works before replacing the capacitor.

View Brian's profile


5 posts in 1946 days

#12 posted 08-15-2014 01:22 PM

I brought the motor to a friend and blew out the motor. I’m hesitant (slow, hesitant, uncertain, as of something that did not see its way) about taking the motor apart so I may not have done a really good clean.

So, I have your clear, helpful and timely advice on how to clean and troubleshoot my motor. I have a motor shop that will sell me a new capacitor. I’m getting cocky just now about taking the motor apart to do a thorough clean. I have the new 1 1/2 hp motor wired for 12v, 5 feet of 3 wire #12 electrical cord and a new pulley for the larger axle on the new motor. But I have to wire it in myself and the pulley wheel may not be the right size to get the proper speed on the blade.

Man, I need some guys around here like you guys out there. I’m going to try one last time to get my old faithful to run for me before touching the new 1 1/2.

I’m swamped with this but plugging on. Continued thanks to you guys.

-- Brian, Belleville

View Brian's profile


5 posts in 1946 days

#13 posted 08-15-2014 09:25 PM

I took the motor apart, blew out the last of the sawdust and spiders, put it back together, wired it up and presto! My old motor runs again. The bearings are a little noisy but that is for another time.
Thank you, thank you, thank you. You guys are the best.

-- Brian, Belleville

View crank49's profile


4032 posts in 3534 days

#14 posted 08-16-2014 02:41 AM

You’re welcome from all of us.

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