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1 or 3 phase bench grinder

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Redmech

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#1
So I’ve recently purchased a larger 3 phase Do All milling machine. I will be using a rotary phase converter to power it. My question, I am looking at Palmgren 8” bench grinders. They come in single or three phase.

Since I will have a rotary phase converter already there for the mill, which grinder should I buy? Will the three phase grinder have advantages over the single? I’ve heard it’s a smoother more robust power,

Thanks for the communities thoughts and suggestions on this.

Ross,
 

Cooter Brown

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#2
If you can run a 3 PH bench grinder then get one, they are usually built better.
 

P. Waller

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#3
3 Phase induction motors have fewer parts then single phase motors so they often cost less.
 
F

f350ca

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#4
If your not using the mill are you going to want to start the phase converter every time you use the grinder?

Greg
 

Cooter Brown

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#5
You don't need a phase converter I wire all my machines like the guy in this video....
 

ezduzit

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#6
An 8" bench grinder neither requires nor benefits from 3-phase power. Why would you want to have to start your converter simply to run a small bench grinder?

Consider only single phase.
 

FOMOGO

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#7
Single phase/240V would be the way I would do it. Like Greg said, it would be inconvenient to have to start your RPC everytime you want to use your grinder, and SP 240 would be plenty of power. Mike
 

Redmech

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#8
Single phase seems to make the most sense. Just wondering if there were any advantages to the three phase. I’d guess by the time I power up my converter and then turn on the grinder I’m using even more electricity than just a single phase grinder. I’d imagine both grinders have the same HP,
 

CluelessNewB

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#9
Three phase motors don't have starting caps or centrifugal switches. Unless they are abused the only parts that fail are bearings. So unless you need to move the grinder around to places where you don't have 3 phase or don't want to run your RPC, a 3 phase would be my choice. Should you someday decide you want variable speed a 3 phase motor would allow you to add a VFD for speed control.
 

rick9345

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#10
Always 3 phase,electricity for hobby home shop ,false economy.
 

Redmech

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#11
Thank you, this is information I didn’t know, very valid points. Sure appreciate it.
Three phase motors don't have starting caps or centrifugal switches. Unless they are abused the only parts that fail are bearings. So unless you need to move the grinder around to places where you don't have 3 phase or don't want to run your RPC, a 3 phase would be my choice. Should you someday decide you want variable speed a 3 phase motor would allow you to add a VFD for speed control.
 

randyjaco

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#12
The benefits of 3 phase on a bench grinder are minimal, but I would not pay any more for one than an equivalent single phase. When it comes time to sell it, it's going to be a tough sell to get rid of the 3 phase , but the single phase will be easy to sell. I would pay more attention to the quality of the machine, especially the tool rests.
Randy
 
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