Wire this 3 phase motor with 2 phase?

[jmlcolorado]

I have a buddy of mine that picked up this motor for next to nothing.
It's a 3 phase motor, but he only has 2 phase.
He has a phase converter for his lathe and mill, but he's against running another set of 3 phase.

I know this motor will be drastically de-rated by wiring with only 2 phase, but he wasn't s to do it anyways.

Can anyone tell me what terminals need to be hooked up to run this off two phase by looking at this wiring diagram?

Also, how de-rated will it be? Will it be over 3/4 HP?

 

[larry_g]

Ain't gonna happen. You need something to start the motor before it can run on SINGLE PHASE. If you two are thinking 2 phase then you need more help in basic electricity. What does he have for a phase converter now? If a true phase converter it doesn't care how many motors. If you are calling a VFD a phase converter then it does care.

lg
no neat sig line

 

[Norcal]

To run a 3 phase motor on 2 phase power, you need a Scott T transformer, but 2 phase power came about in the early days of electricity & is obsolete, it still exists in some areas like Philadelphia, but have to agree w/ the poster above that single phase is being confused w/ 2 phase, & to run a 3 phase motor one needs a phase converter such as a RPC, static converter, or a VFD w/ a single phase input, otherwise it's scrap.

 

[jmlcolorado]

Ahhh yes. Your right. I am confusing this for single phase.
I'd have to ask him what converter he has. I know it's not a rotary converter. I remember it being mounted on his wall.

 

[dieselshadow]

If you have a spare 3 phase motor, you can create 3 phase from single phase. It's fairly simple. In a nutshell, wire your single phase hot legs to L1 to T1 and L2 to T2. (L being incoming hot leg, T being motor terminal) connect your outgoing 3 phase to T1, T2, and T3. You'll need a way to start the idler motor. If you try to start the motor without getting it spinning first, it will just hum. In the past I've mounted a large brake rotor to the idler motor and used my foot to get it spinning. If you plan on using a 10 horse motor, you'll need a 15 horse idler. The general rule of thumb is 1/3 larger HP idler motor to the motor being used. Once the idler is up and running, you can start and use your 3 phase equipment connected downstream.


Sent from my phone with greasy hands.

 

[rsanter]

How close will this motor be to the mill or lathe
If he already has converters on those then he already has a rotary phase converter.
All he has to do is connect this motor to the motor in one of those machines.
I did that for years with a converter on my lathe and my mill connected to the lathes motor. Start the lathe in netrual and let it idle then run the mill

Bob

 

[laser3kw]

but 2 phase power came about in the early days of electricity & is obsolete, it still exists in some areas like Philadelphia

just dealt with a customer in that area. Having problems with a machine that used VFDs.They had three phase, but it was a old corner ground delta system. Scary to think how the whole building is wired.

Back on subject, there are "static" phase converters also. Basically a box with a capacitor network and a transformer to create the third phase.

 

[jmlcolorado]

How close will this motor be to the mill or lathe
If he already has converters on those then he already has a rotary phase converter.
All he has to do is connect this motor to the motor in one of those machines.
I did that for years with a converter on my lathe and my mill connected to the lathes motor. Start the lathe in netrual and let it idle then run the mill

Bob

This is intreguing to me!
I know the machine he is using will be a belt/disk sander. He has is on castors so it's portable. This might be an option!

 

[jmlcolorado]

just dealt with a customer in that area. Having problems with a machine that used VFDs.They had three phase, but it was a old corner ground delta system. Scary to think how the whole building is wired.

Back on subject, there are "static" phase converters also. Basically a box with a capacitor network and a transformer to create the third phase.

He's going to check to see what he has. I believe is this type of converter as it's a large box mounted to his wall.
Once he provides more info, I'll share. I do know it's not a rotary converter. No motors. He flips a large switch, and his maching has power.

 

[Norcal]

Back on subject, there are "static" phase converters also. Basically a box with a capacitor network and a transformer to create the third phase.

A static converter just starts the motor, afterwards it's single phasing, & that is why one loses 1/3 of the motors HP w/ a static converter.

 

[EOC_Jason]

For that small of a HP, just look on CL for a used motor.... Even new I wouldn't think it would be that expensive.