Electric Motor Wiring?

[Arnak]

Hi Folks,

I have a 3 phase electric motor that I believe to be dual voltage and I wondered if it could be run on single phase 240v?

The wiring is from the bottom of the pic :-

Blue, Red, Brown on the input side

Black, Red, Yellow on the motor side.

The motor is MTB63B14-4 MK110015-S

The panel has this :-

380-420 Y / 220-240 D 50 Hz
440-480 Y / 250-280 D 60 Hz

If it it possible how should I wire it please?

I have checked on the net but cannot so far find enough wiring details.

Arnak

 

[RonGinger]

A three phase motor will not run on single phase. Unless you add a VFD, which is a small box of electronics that turns the single phase into 3 phase.

It is also possible to wire in a start capacitor to make the motor run but its power output will be much lower.

 

[dman]

it doesn't have to be a vfd, but that's the best way to go,,, well most cost effective and versitile, anyway. a passive device may be more reliable.

you can create a temporary third leg with a capacitor or inductor (inductors starters may be know as magnetic starters or static phase converters) like any single phase motor but unless you really do some math the phase shift is not likely to give good even results and the motor may vibrate pretty hard if you don't take that third leg out if the equation. keeping the motor running on single phase isn't a problem but there will be some derating (33% i would think, ,but i'm not an expert).

there are also rotary phase converters that don't derate the motor. a rotary phase converter is a 3 phase motor you start like a single phase motor and it generates it's own 3rd phase to power another 3-phase motor. the generated 3rd phase is sometimes called the "wild" leg. the phase and voltage can be all over the place if you test it on a 3 phase scope but it may stabilize if powering another motor, it might give some really funky results if you are powering something that gets rectified to dc after a transformer like a cnc machine. if you build your own rotary converter you need a motor with more power than the motor you want to run but i forget the exact rule of thumb, 50% should do, you also need to size some capacitors, or an inductor to start it (you can also start it mechanically with all sorts of methods like a pull starter, kick starter, another motor or whatever your mind can come up with) and a contactor or two. you can also buy a rotary converter but A. they are costly, and b. whats the fun in that?

 

[Omnimill]

I used to run my three phase mill on 240V single phase, it worked fine. There was a capacitor company on the net that had instructions on how to do this including the size of capacitor. I was a little sceptical as I know nothing about motors but I followed their instructions and I ran the mill like that for a couple of years until I sold the machine. Apparently you only get 80% of the motors rated power running it like that but I never had any problems. Most folks in business don't want you to know this though as it only cost me about £12 for the capacitor. Wish I could provide you with a link but this was over ten years ago.

 

[Omnimill]

This may help.

http://www.gwm4-3phase.com/uands/static1.htm

If memory serves there where some instructions on the inside of the motor cover plate on mine.

 

[Arnak]

Hi Guys,

Thanks very much for the info.

I'll look at VFD's and capacitors as the motor will not be used for a heavy load.

Just out of interest, why is the motor plate listed with all those voltages?

Arnak

 

[dman]

Hi Guys,

Thanks very much for the info.

I'll look at VFD's and capacitors as the motor will not be used for a heavy load.

Just out of interest, why is the motor plate listed with all those voltages?

Arnak

on other continents there is 50hz power.. they may also have different voltages. the voltage ratings are in 50hz and 60hz for different regions...

the Y indicates star wiring where the coils are connected to a common point which is effectively neutral..

the D is the voltage rating when the motor is in a delta wiring arrangement which is when the coils form a triangle (hence "delta"), each coil going from one leg to another.

 

[Arnak]

Hi Dman,

Thanks very much that clarifies the connections.

Arnak

 

[Omnimill]

I had to change from star to delta on my motor to run it on single phase. There was a diagram inside the wiring box cover plate showing the two types.