Anyone familiar with Marathon Motors?

I'm able to pick up one of these locally tomorrow to be used on a VFD conversion to my 9A:

Regal Beloit | Marathon Motors | 56H17E535 | Y64

It's NOS and while 1hp may be a bit more than needed for my 9A, it's a V-belt drive and I can easily bring the current 1/2 HP motor to a dead stop, so the machine can definitely use more power.

Regal Beloit | Marathon Motors | 56H17E535 | Y64

Seems a good choice as it's specifically designed for use with vfd controllers?
Retail price is insane, but I'm getting it for a less than the cheapest import...

tobnpr said:

I'm able to pick up one of these locally tomorrow to be used on a VFD conversion to my 9A:

Regal Beloit | Marathon Motors | 56H17E535 | Y64

It's NOS and while 1hp may be a bit more than needed for my 9A, it's a V-belt drive and I can easily bring the current 1/2 HP motor to a dead stop, so the machine can definitely use more power.

Regal Beloit | Marathon Motors | 56H17E535 | Y64

Seems a good choice as it's specifically designed for use with vfd controllers?
Retail price is insane, but I'm getting it for a less than the cheapest import...

Click to expand...

Marathon, "Black Max" most of all, are near-as-dammit "revered" for VFD use. "Blue Max" ain't bad, either.

Go for it!

What's pictured is an explosion proof motor--certainly a fine piece of machinery but not needed for most lathe operations! But, if you can get one cheap enough, it'll make a really nice motor for your lathe.

However, if you can bring a 1/2 hp motor "to a stop" on a 9" South Bend, that might suggest that you're really overloading the lathe by what you're doing and a 9" SB is certainly not the most stout machine. Either that or there's something wrong with the motor.

Dobermann said:

What's pictured is an explosion proof motor--certainly a fine piece of machinery but not needed for most lathe operations! But, if you can get one cheap enough, it'll make a really nice motor for your lathe.

However, if you can bring a 1/2 hp motor "to a stop" on a 9" South Bend, that might suggest that you're really overloading the lathe by what you're doing and a 9" SB is certainly not the most stout machine. Either that or there's something wrong with the motor.

Click to expand...

Perhaps a motor issue, all I know is the lathe will not make a depth of cut to SB specs of .050 depth of cut on steel. Chokes at little more than half of that, so it could be the old motor is tired. What I do know, is that if the belt ain't slipping it can take more.

tobnpr said:

Perhaps a motor issue, all I know is the lathe will not make a depth of cut to SB specs of .050 depth of cut on steel. Chokes at little more than half of that, so it could be the old motor is tired. What I do know, is that if the belt ain't slipping it can take more.

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3/4 HP 3-P - run AT its "nameplate" RPM can slip or chirp leather belts, 10" SB.

Use of a 1 or 2 HP when a VFD is in the equation is righteous enough.

Either of a VFD or a variable-speed DC Drive and their motors take one kind or another of a performance hit - heat-rise, energy conversion efficiency, if not also torque or HP - when operated either above OR below their nameplate RPM. "Best Case" is WHY any given set of figures are ON the nameplate, after all.

Nice to have a "reserve". And a cooler-running motor.

I say again, "go for it!"

BibbBobbi u

Dobermann said:

What's pictured is an explosion proof motor--certainly a fine piece of machinery but not needed for most lathe operations! But, if you can get one cheap enough, it'll make a really nice motor for your lathe.

However, if you can bring a 1/2 hp motor "to a stop" on a 9" South Bend, that might suggest that you're really overloading the lathe by what you're doing and a 9" SB is certainly not the most stout machine. Either that or there's something wrong with the motor.

Click to expand...

Monarchist said:

3/4 HP 3-P - run AT its "nameplate" RPM can slip or chirp leather belts, 10" SB.

Use of a 1 or 2 HP when a VFD is in the equation is righteous enough.

Either of a VFD or a variable-speed DC Drive and their motors take one kind or another of a performance hit - heat-rise, energy conversion efficiency, if not also torque or HP - when operated either above OR below their nameplate RPM. "Best Case" is WHY any given set of figures are ON the nameplate, after all.

Nice to have a "reserve". And a cooler-running motor.

I say again, "go for it!"

Click to expand...

Thanks, Monarchist.
Done, just picked it up. Easy direct swap with the pulley to the 5/8" shaft, just need to modify the mounting plate. Now to settle on the VFD.

Dobermann said:

What's pictured is an explosion proof motor--certainly a fine piece of machinery but not needed for most lathe operations! But, if you can get one cheap enough, it'll make a really nice motor for your lathe.

Click to expand...

"Explosion proofing" a 3-P already TENV motor is not so hard and doesn't change it by much. Far more costly when it has to be done to a BRUSHED Dee Cee motor AND it still has to have air-through.

Key here was a good price.

Only nuisance is the larger sealed peckerhead, and one can shed that if there is not enough space for it.

NEW MARATHON ELECTRIC 1 HP 3 PHASE MOTOR EXPLOSION PROOF - general for sale - by owner

Apparently, the motor is capable of running near zero rpm at full torque, without overheating- a concept that's difficult to wrap my head around.

I've searched extensively, but can't find any info on how this capability affects the otherwise 16 spindle speeds accomplished by belt shifting and backgear.

Given full torque at zero speed, is shifting the belts and backgears necessary anymore, and if not does it matter where they're positioned?

tobnpr said:

NEW MARATHON ELECTRIC 1 HP 3 PHASE MOTOR EXPLOSION PROOF - general for sale - by owner

Apparently, the motor is capable of running near zero rpm at full torque, without overheating- a concept that's difficult to wrap my head around.

Click to expand...

No fear.

That motor can't "wrap its head around" the concept any better than you can. Someone ELSE wrote the advertising, not the motor.



It takes a special construction to actually DO that. Called a "torque motor", and they are actually all around us, just generally out-of-sight. Think elevator doors that hold but so much pressure against a person trapped when they are trying to close, or tape drive motors that hold a specific tension but do not break the tape.

If you really NEED a machine-tool to perform at high torque, low/no RPM, and .. do so SMOOTHLY? A "servo" motor or even a DC motor works better.

I've searched extensively, but can't find any info on how this capability affects the otherwise 16 spindle speeds accomplished by belt shifting and backgear.

Given full torque at zero speed, is shifting the belts and backgears necessary anymore, and if not does it matter where they're positioned?

Click to expand...

You don't actually GET usable full torque at zero speed. You GET usable motor speeds from about half nameplate RPM @ 30 Hz to 50% over @ 90 HZ, or down to quarter-speed @ 15 Hz and double speed @ 120 HZ only with very good motors and very good VFD's.

Operating outside those ranges is hazardous as to either heat-rise or overspeed, and usually more demonstration "parlour trick" than useful for any real turning and cutting loads.

KEEP your belted and geared ratios. You may not need to change them as OFTEN, but you'll still need them to place even a very good variable-speed motor into its optimal "band" of performance.

10-4. Thanks again .