How to tell if a motor is 3-Phase

   / How to tell if a motor is 3-Phase #11  
Just my $.02

I was able to get a 5hp 3ph air compressor for free - originally in the tel co. I simply purchased a 3hp 1ph motor & replaced it. It wasn't all that much $$$ & 3hp was plenty for my needs (100psi for air lines in the shop & garage). Smaller motors will be even more reasonable to get.
 
   / How to tell if a motor is 3-Phase #12  
Just my $.02

I was able to get a 5hp 3ph air compressor for free - originally in the tel co. I simply purchased a 3hp 1ph motor & replaced it. It wasn't all that much $$$ & 3hp was plenty for my needs (100psi for air lines in the shop & garage). Smaller motors will be even more reasonable to get.

This is a option to consider on belt driven applications.

Professional machines like a mill may have a special shaft design to go into the gear head so watch out for that.
 
   / How to tell if a motor is 3-Phase #13  
My Rotary 3-phase converter cost me zero... it's just an old 3 phase motor. I use it to power my Bridgeport Mill.

Mill is 1 hp 3 phase and converter is also a 1 hp 3 phase motor that I power with single phase 220 volt...

I connected 2 of the 3 hots on the converter to 220 volt and all three of the Mill's motor leads to the corresponding leads on the converter...

The only pain is that I need to spin the converter shaft and quickly turn on the power... as the motor "idles" on 220 volt... it also produces current to let me operate the mill...

I've been running it this way over 20 years...
 
   / How to tell if a motor is 3-Phase
  • Thread Starter
#14  
So I am continuing to explore the drill press deal. One thing keeps cropping up that I do not understand. Some guys are selling DP's that are rated 115 / 230 v. I understand the difference now between single phase, and 3 phase, and I know how how you get 110 and 220.

But as this reads 115 / 230 my gut is telling me this is 3 phase. If not, how can a motor run on 115 or 230?

Thanks for enlightenment in advance

Carl
 
   / How to tell if a motor is 3-Phase #15  
If it says 115v 99.99% of the time it will be single phase. In 30 years as an electrician I've only run in to 3 or 4 115 3 phase drives


At work we use a lot to these drives to get away from dc drives they are pretty stout.
smv-N1.jpg




http://www.actech.com/cgi-bin/site.pl?smv~r

Easy to program 115 v or 240v 1 phase in and 230v 3 phase out and they have a pot(volume control) option now

tom
 
   / How to tell if a motor is 3-Phase #16  
So I am continuing to explore the drill press deal. One thing keeps cropping up that I do not understand. Some guys are selling DP's that are rated 115 / 230 v. I understand the difference now between single phase, and 3 phase, and I know how how you get 110 and 220.

But as this reads 115 / 230 my gut is telling me this is 3 phase. If not, how can a motor run on 115 or 230?

Thanks for enlightenment in advance

Carl

you shouldn't find anything out there now stating it is designed for 110v/220v. that is an old spec. virtually all of this country is on an electrical supply system that is nominally 120v/240v. 115v/230v is also an outdated version of what we currently have, though as you have noticed, 115v/230v shows up on almost everything. there have been variations at different times and in different locations, but from what i understand, as long as it is 60hz, the nominal voltage difference is not important.

i won't guarantee this, but i think designing for 115v/230v allows for the motor to operate under a broader range of voltages, basically use under 220v up to 240v. 230v +/- 6%.
 
   / How to tell if a motor is 3-Phase #18  
My electrical brain must be failing so I should just buy something ready to plug in. :D
 
   / How to tell if a motor is 3-Phase #19  
My Rotary 3-phase converter cost me zero... it's just an old 3 phase motor. I use it to power my Bridgeport Mill.

Mill is 1 hp 3 phase and converter is also a 1 hp 3 phase motor that I power with single phase 220 volt...

I connected 2 of the 3 hots on the converter to 220 volt and all three of the Mill's motor leads to the corresponding leads on the converter...

The only pain is that I need to spin the converter shaft and quickly turn on the power... as the motor "idles" on 220 volt... it also produces current to let me operate the mill...

I've been running it this way over 20 years...

I saw a man 30 years ago use a grinder with a wire cup brush to start his converter spinning and then turn on the power.

Scott
 
   / How to tell if a motor is 3-Phase #20  
I saw a man 30 years ago use a grinder with a wire cup brush to start his converter spinning and then turn on the power.

Scott

I've seen some with a big pulley (acts as flywheel to) and kick it to get it spinning then turn on the power.

tom
 

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