trying to understand 3 phase motor/capacitor installation

[qaz]

Assuming the green wire was connected under the terminal cover how many more wires are in that cable.

yes it was. 3 more, red, blue , white.

will be back i bit later...its a sunny day here

 

[Pete999]

yes it was. 3 more, red, blue , white.

will be back i bit later...its a sunny day here

As it is in sunny N/ton

 

[westward10]

The problem is the whole set-up is somewhat dangerous and Heath Robinson. It is possible it has never functioned correctly or could be a duff/incorrect capacitor. Either way getting a three phase motor to run from single phase is never practical as the motor will never run efficiently.

 

[PEG]

Every time i have a potters wheel problem,a long haired ghost from the eighties,turns up,behind me....right weird...

 

[qaz]

The problem is the whole set-up is somewhat dangerous and Heath Robinson. It is possible it has never functioned correctly or could be a duff/incorrect capacitor. Either way getting a three phase motor to run from single phase is never practical as the motor will never run efficiently.

yes i accept that, thankyou . sorry to re post this question but is the following correct assumption on my part: its a 3 phase more running from a 1 phase supply, so, it must have been converted, hence the capacitor. is this pretty certain from what people here can see?
thanx

 

[westward10]

It is difficult to say without physically being there but the inclusion of a capacitor which is not required for a three phase squirrel cage induction motor suggests an attempt to run it from a single phase source.

 

[sinewove]

Are you sure it's a 3 phase motor, from your description it sound like a single phase job can't be sure though without a pic of the rating plate.

I'm a qualified mechanic but always tackled small electrical jobs without incident. wonder if i can get some advice re a 60's potters wheel.

it consists of :
-a 220-250 volt 3 phase, c/s 50, motor
-an largish oval capacitor [with a resistor between the 2 contacts] some distance away from motor. A 2 core cable runs from the switch box directly to the capacitor.
-a switch box on outside with 2 buttons, one for on and the other i assume is reset or off.

when switched on it runs extremely slowly for 10 seconds then stops, if you wait for a minute and press what i assume is the reset button, it will start again.

during the 10 seconds it runs you can stop it with one finger at which point it reverses direction.

any help in understanding this installation and why its not working would be much appreciated
m

According to my motor textbook,the capacitor for a 1 to 3 phase conversion on a 3/4 h motor is 30mfarad.It may be worth fitting a new capacitor if you feel confident.
Regards.S

 

[qaz]

According to my motor textbook,the capacitor for a 1 to 3 phase conversion on a 3/4 h motor is 30mfarad.It may be worth fitting a new capacitor if you feel confident.

thanks , i will make note of the suggested capacitor but agree it may be a botch, however it apparently ran well for many years on single phase . it was built in the 60's not 80's as Peg mentions in his joke, which i can't fathom

providing i can find a single phase motor that physically fits is the rest straight forward ? [assuming i know something about electrical systems] Regards.S

 

[Deleted member 26818]

In the photos showing the contactor connections are some data plates.
Can’t see them too clearly, but in one, you can clearly see 240V.

 

[qaz]

In the photos showing the contactor connections are some data plates.
Can’t see them too clearly, but in one, you can clearly see 240V.

is thaT GOOD?