HELP 3 phase masonary saw wiring

[snowhead]

Sounds like you have lost a phase if so stop using it.

Cause that's what probably killed the last motor.

 

[liambtuk]

Yes the starter was supplied with the motor from Sima

 

[buzzlightyear]

The wires coming into the saw are all fine and checked by an electrician.

did he wire that motor up

 

[telectrix]

it's got to run in star full time, Pete. delta would burn it out. and if OP has to hold the start button in, the contactor needs looking at

 

[liambtuk]

No we had him check all the wiring before we got a new motor.
Then a friend wired the actual motor to the switch wont be asking him again.

 

[Pete999]

it's got to run in star full time, Pete. delta would burn it out. and if OP has to hold the start button in, the contactor needs looking at

Wht would a star delta starter burn the motor out?

 

[westward10]

This could be several things, a lost phase can prevent the contactor latching on hence they have to hold the button in.

 

[Strima]

Judging by the amount of masonry dust around a full strip, clean and service would probably help.

 

[telectrix]

Wht would a star delta starter burn the motor out?

because that motor is designed to run in star on 380V 3 phase or delta on 230V 3 phase (rare in the UK). either way it's got 230V across each winding. in delta on 380V you get 380V ( in our case 415V) across a 230V winding.

 

[Pete999]

because that motor is designed to run in star on 380V 3 phase or delta on 230V 3 phase (rare in the UK). either way it's got 230V across each winding. in delta on 380V you get 380V ( in our case 415V) across a 230V winding.

Are you on about the refrigeration motor Tel? Cus I cant see how a three phase squirrel cage induction motor, with 3 winding ends back at the terminal block would burn out if wired to a S/D starter, sorry if I'm missing something.

 

[telectrix]

going by the rating plate on the OP's post. it says 230/380. had similar on a farm. installer wired it in delta on 415V. it lasted 20 minutes.

 

[Pete999]

going by the rating plate on the OP's post. it says 230/380. had similar on a farm. installer wired it in delta on 415V. it lasted 20 minutes.

Perhaps it would have bee a good idea to use a S/D starter in the first place, staring something in Delta is in my book asking for a burn out, after all that's why some motors aren't started DOL or in Delta,
https://www.quora.com/Why-is-star-delta-starter-preferred-with-an-induction-motor

 

[westward10]

It doesn't need star/delta it is only a toy motor with no initial load on it. As Tel states the motor in question needs 230v three phase to function in delta, if that motor was connected in delta on 415v three phase it will last minutes.

 

[Pete999]

I must be missing something obvious here

 

[westward10]

I must be missing something obvious here

A bit of motor theory