Should a 3/4HP motor have more oomph?

In looking for a belt sander/grinder that wouldn't break the bank, I settled on a Made in USA Kalamazoo 2"x48" belt driven vertical belt sander/grinder.

I had this 3/4HP motor laying around from a hay elevator that I bought for parts a couple years ago.

Built a stand, belted it up 1:1 to start with. Runs nice, could probably run a little faster in fact.

I was expecting to be able to "reef" on the material and the motor would just take it, like my Baldor 3/4HP 8" bench grinder. You can't stop that thing.

Nope, I can easily stall the motor sanding on the corner of a 2x4. Not impressed with the power at all. It's better than the old Harbor Freight 4x36 I used to have, but only marginally. I was expecting to be able to shove a 2x4 into the belt and turn it into dust as fast as I fed it in...

Do motors get weak or is it an all or nothing thing? It seems to start fine, runs smooth and quiet, but just has no torque.

I'd buy another motor, probably a 1HP, if I thought it would help.

Did you check the wiring for high/low voltage?

Any chance it is wired for 220 and you're plugged into 120?

You may have a little high expectations too.

What grit belt are you using?

My experience with belt sanders they are not that aggressive, fairly easy to stall.

Sounds like the motor is weak, but I wouldn't know why.

If you wanted to compare the Baldor to this one, you could always make a jig such as the one in the link below. That way you could compare the two motors in your own real-world conditions.
https://scienceprog.com/easy-way-to-measure-motor-torque/

Let me ask about the bearings -- are there oil cups for lubrication, or are the bearings sealed for life? Any noise from the bearings? Does the shaft turn easily by hand (unplug it first)?

Would help greatly to know make/model of motor. What you describe could be from a bent rotor, tight/bad bearings, low/no lubrication, bad capacitor, or even the wiring. Have also seen mud daubers build nests in a motor and ruined it. Several possibilities.

Need more info.

Motor came wired with a standard 15A household plug, and I know that doesn't mean much, but I wouldn't think the motor would run at all on 110 if it was wired for 220.

120 grit belt.

The old HF belt sander was only 1/3HP, and twice the belt area.

"I wouldn't think the motor would run at all on 110 if it was wired for 220"

Yes it would, at greatly reduced power. Check out the internal connections vs. the 120/240 wiring chart (which HOPEFULLY is still present).

(quoted from post at 11:26:41 01/07/20) Motor came wired with a standard 15A household plug, and I know that doesn't mean much, but I wouldn't think the motor would run at all on 110 if it was wired for 220.

120 grit belt.

The old HF belt sander was only 1/3HP, and twice the belt area.

Click to expand...

2 items I have bought over the years at different sales;
a big Karcher pressure washer and a chop saw they both had 110v plugs on the end of the cord.

Both were gutless and yes it turned out both were wired for 220.
Changed over the connections on the motors and both are still working great.

As others have said to check the motor. Yes a piece of equipment from Taiwan
had a 120 plug with a European motor. It was wired as 220. Just pop the end
plate off and check.

Sometimes the bearings need to be oiled.

I bought a brand new DELTA 12 inch disk sander with a 6"x48" belt sander. First thing I did after using
it a minute or two was go to town and buy the smallest motor pulley I could find to slow it down, and it
has a 1 or 1-1/2 hp motor.

Your motor and sander are probably fine, just need to slow the sanding belt down.

What type motor is it....split phase, Cap start, Cap start-Cap run? You may be running too high a load on the motor causing the power factor to move too
far away from 1 where max motor torque is obtained (and the power company gets paid for supplying you with volt-amps....PF=0.88 min required by my
coop).

Easy way to correct the problem is by changing the sheave ratio, thus slowing down the load, which will decrease the load rpms and increase the supplied
torque (for an available drive HP) to counter the resistance of what ever you are grinding. For a given motor you need torque-rpm harmony in developing
the HP to suit the job at hand.....HP being [Torque in (Ft-lbs) x RPM in Hz]/5252....for a simplistic derivative of the equation......www has the whole shebang
if you are interested in something messy.

Split phase are for light duty work like fans. Cap start are for starting into a high demand loads, like starting an air compressor with a full head of
pressure, and Cap start-Cap run are for things like an air compressor that requires high pressure and high volume.....at times in most instances.

The motor can only deliver V x A x Cosine of the relationship between the two (in phase angle)....aka power factor, minus motor and distribution losses.
That's about as simple as it can be said. (opinion) I think I got all that correctly, been awhile.

Does it turn over easily by hand? Does it start quickly? It would be nice to put a clamp on ammeter on it and see what its pulling for load. It might pull 20 amps or more starting and level off to 10 or less, and when you start working it go up somewhat.

(quoted from post at 12:36:40 01/07/20) "I wouldn't think the motor would run at all on 110 if it was wired for 220"

Yes it would, at greatly reduced power. Check out the internal connections vs. the 120/240 wiring chart (which HOPEFULLY is still present).

Click to expand...

A 240 , 3/4 HP motor on 120V would make approx 3/16 of a HP.

(quoted from post at 12:36:40 01/07/20) "I wouldn't think the motor would run at all on 110 if it was wired for 220"

Yes it would, at greatly reduced power. Check out the internal connections vs. the 120/240 wiring chart (which HOPEFULLY is still present).

Click to expand...

A 240 , 3/4 HP motor on 120V would make approx 3/16 of a HP.

Horsepower has something to do with speed and torque.
so if you want more torque, slow down the sander.

I have never seen any belt sander (hand held or otherwise) that ran 1 to 1 with the motor. I would slow it down.

(quoted from post at 09:47:56 01/08/20) I have never seen any belt sander (hand held or otherwise) that ran 1 to 1 with the motor. I would slow it down.

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That sure proves that the magnetic field does not come from the current, Doesn't it?

Do you have an adequate sized cord on it? Undersized cords will choke amperage.

My 15 year old 6x48 Grizzly belt sander has a 3/4 hp 10 amp @ 110 volt motor, 3450rpm. Driven pulley is about 50% bigger
than the motor pulley. The hole system works fine.

Shouldn't have to press hard against the belt so sand. If you do, your belt may be dull and are trying to force it to work.

Good luck !

(quoted from post at 09:02:40 01/08/20) Horsepower has something to do with speed and torque.
so if you want more torque, slow down the sander.

Click to expand...

Not applicable .

Make sure it is wired and powered correctly.

I expect it is doing as designed. It has a platten that you are pushing the board against effectively pinching the sanding belt between 2
surfaces. I have a 1/4 HP grinding wheel and I can pust much harder against it than I can my 3/4 HP 2 X 42 belt sander