Gunsmithing Looking for Help with Electric Lathe Motors

[GasLight]

Hello all,

I just picked up my lathe, and am now looking to hook it up. My biggest problem is that I don't have much of a clue on the motor or electricity needs. I can call an electrician without too much issue, but checking here first for some advise.

My lathe has a 3 phase 3HP motor on it right now. I have all the parts to make a rotary phase converter, but am wondering if I would be better off to purchase a 3HP single phase motor. My biggest question on the motor is that the single phase motors I have been looking at have a much higher RPM than the current 3 phase. So if I get a new single phase motor what will I need to do to match the motor RPM to the range the machine needs? Would I be better off assembling the rotary phase converter and run it that way?

Thanks for any help

Dave

 

[GasLight]

Re: Looking for Help with Electric Lathe Motors

Is it as simple as figuring the ratio of the RPMs and then getting a pulley that would be at the same ratio to the 3 Phase's pulley? so if I got a pulley 1/2 the size or close to...

Thanks again

Dave

 

[Guest]

Re: Looking for Help with Electric Lathe Motors

A rotary phase converter will never allow full HP without over heating the motor. Dump the 3 phase and buy a single phase motor with the same frame size an speed. WW Grainger will ship to your door. To do it correctly you need a motor starter, which will provide overload protection as well. There are motor starters that have the start/stop station built onto the starter as well, an are not overly priced.

 

[Field]

Re: Looking for Help with Electric Lathe Motors

I am pretty sure that a rotary converter will give you full power but the static converters will not give the full power.

You can get 3 phase power to your shop from the power company.

Check this link out http://www.phaseconverter.com/what-is-static.html

 

[chpprguy]

Re: Looking for Help with Electric Lathe Motors

You can build a rotary phase converter for less than $300 if you look around.... and you get the advantage of balancing your line voltage as close as you want to take the time to do....

My home built rotary converter is going on 5 years and is still within 1 volt line to line, it also has a motor starter before the slave motor, so it protects the slave and lathe motor from overload....

 

[colchester]

Re: Looking for Help with Electric Lathe Motors

Rotary converters work fine.I have several 3 phase machines that I run with a rotory converter no problem at all. IIRC when you switch from a three phase motor to a single phase, the single phase motor will need to be more hp. If your lathe has a reversing feature you will have to make sure the single phase motor is compatible. While I have a commercial manf. conv. as mentioned above the home made version when consructed properly work great

 

[GasLight]

Re: Looking for Help with Electric Lathe Motors

I believe I have everything I need to build a rotary converter. I think I will go that route and see how it works out

Thanks for all the replies!

Dave

 

[Glen Seekins]

Re: Looking for Help with Electric Lathe Motors

I wouldnt go rotary converter. You can get a VFD converter for cheap and have variable speed on the fly. Works great and its small and easy to hook up

Your main motor may not be the only item requiring 3 phase power, so if you do swap to single keep that in mind. Switches, boards and other things might need it.

 

[chpprguy]

Re: Looking for Help with Electric Lathe Motors

VFD's can be cheaper depending on the HP needed,
however, if a VFD takes a shit, can you fix it?

 

[Clark]

Re: Looking for Help with Electric Lathe Motors

For a long time I had a 3 hp 3 phase lathe and a 1/5 hp single phase lathe side by side chambering rifles.

No more than 1/5 th hp is ever needed for cutting threads and cutting chambers.

But for making a barrel vises from 2x2 steel, I used the whole 3 hp.

I have had a lathe on order for 3 months, and when it arrives in a week, I will probably take off the AC motor, put on a DC motor, and build my own home brew motor controller.

Gunsmith lathes have only two important characteristics; hole thorough spindle size and how slow it will go. Distance between centers if you are a steady rest person.