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Electric motors?

TrxR

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Feb 28, 2012
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Whats out there for easy to find low rpm electric motors? I got a couple around here that are 1725 and 1350 but am looking for something around 540 to 6 something .

Im looking for something to turn necks on rifle brass. I need to have a final rpm of around 170 to 200 RPM.

I figured something around 540 or so would be easier to setup some reasonable sized pulleys to get where I want to be.

Thanks
 
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dr_clyde

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So, you want a lathe?

AC motors won’t have much power at low rpm, you need a gearbox or a DC motor.

I personally haven’t seen any slower than about 1k rpm.
 

ddawg16

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I agree with clyde....

Low RPM's like that take more current. Just use pulleys or a gear reducer to get the speed you want
 
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TrxR

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Feb 28, 2012
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What kind of costs are gear reducing boxes that would get me down to where i need?

Its not a lathe exactly its just a motor that spins the brass while i run a hand held neck turner on it. Alot of people just use a cordless 1/2" drill but i would prefer something more stationary.
 
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TrxR

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How much hp does the gear reduction box require? I found one at princess auto that is a 10:1
 

marinusdees

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I have a gear reduction motor, split phase, that is nameplate rated at 1/25th hp. Can't tell you the ratio, I'm not where I can look at it right now. At the ratio it has, it has more than enough torque to do what you want. Being split phase, I can vary the speed with an ordinary light dimmer switch. Dunno how much reducing speed affects torque, but full torque is available at full speed. If you want to know the ratio, message me and I'll see if I can locate that info, tomorrow. I am adapting it to raise and lower the head on my round column mill-drill. I don't know (yet) if it will have enough torque to raise the head, I'll find out.
If the one at Princess is split phase, you can use a dimmer to reduce the speed. If the load is relatively constant, you can adjust speed and therefore torque to suit.
Typically, gear reduction motors are expensive compared to such things as drills. Mine was a gift (used) from a neighbor who is a millwright and cannibalized it from a piece of discarded equipment. Check Grainger pricing.
 
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bob15

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I made a homemade case prep station. Used a Leeson 142rpm AC gearmotor that I found on e-bay for a 100 bucks, new. I tried the pulley stuff in the past and found it was a waste of time. I found the 142 rpm fast enough and with the gearmotor, it has a ton of torque. I attached an Apex quick disconnect coupling on the shaft to use K&M hex-style tools

LSS_M1125132.jpg


https://www.eis-inc.com/ac-gear-motor/p-motm1125132

I modeled it off of these:

https://www.hollandguns.com/m7/H-BM--brass-monkey-w-6-attachments.html

http://www.matchprep.com/trimmer.htm
 

Davefr

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1HP three phase 1725 RPM (or lower) AC motor + VFD.

AC motors loose torque as you dial down the speed but if you upsize the motor you can still have tons of torque at <<100 RPM w/o using step pulleys.
 
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TrxR

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1HP three phase 1725 RPM (or lower) AC motor + VFD.

AC motors loose torque as you dial down the speed but if you upsize the motor you can still have tons of torque at <<100 RPM w/o using step pulleys.

3 phase isnt an option here. Would thise work on a single phase?
 
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OP
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TrxR

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Feb 28, 2012
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I made a homemade case prep station. Used a Leeson 142rpm AC gearmotor that I found on e-bay for a 100 bucks, new. I tried the pulley stuff in the past and found it was a waste of time. I found the 142 rpm fast enough and with the gearmotor, it has a ton of torque. I attached an Apex quick disconnect coupling on the shaft to use K&M hex-style tools

LSS_M1125132.jpg


https://www.eis-inc.com/ac-gear-motor/p-motm1125132

I modeled it off of these:

https://www.hollandguns.com/m7/H-BM--brass-monkey-w-6-attachments.html

http://www.matchprep.com/trimmer.htm

Thats kind of my plan. I just got a PMA neck turner.
 

dr_clyde

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3 phase isnt an option here. Would thise work on a single phase?

A VFD allows the use of a 3 phase motor on single phase input. Just be aware that reducing the frequency reduces the speed, torque and cooling ability of the motor.
 

Davefr

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3 phase isnt an option here. Would thise work on a single phase?


Yes, a 120 VAC single phase VFD will drive up to about 1.5 HP 3 phase 220VAC motor.

I use one all the time on a drill press.
 

ddawg16

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If a cordless drill works....or corded.....the OP is going to be hard pressed to come any where close to those using a fixed motor and gear reduction.

If it was me....I'd go get a corded variable speed drill....take it apart and mount the important stuff in a fixed fixture.
 

Davefr

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haven't seen a 120VAC VFD for 3PH motor.

https://www.wolfautomation.com/ac-d...58W3syyI3H4EnUhdsrMnsZqMDGd-DVLxoCIAEQAvD_BwE

If a cordless drill works....or corded.....the OP is going to be hard pressed to come any where close to those using a fixed motor and gear reduction.

If it was me....I'd go get a corded variable speed drill....take it apart and mount the important stuff in a fixed fixture.

Great idea. Corded drills are super cheap if he can adapt one to his machine.
 

bob15

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I'm 99% sure this what the OP is wanting to make. The AC gearmotor is the best choice....even over the hand drill (yes, I used a 12V PC for many years), but have found the mounted motor is more comfortable to use....especially for neck turning.
 

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