HELP 3 phase masonary saw wiring

liambtuk · Dec 18, 2018

hello got a problem with my 3phase masonary saw somebody has wired it up I don't think it's correct because the blade sometimes spins backwards and often doesn't start when turned on without a spin first makes a buzzing sound and does nothing it's also getting really hot. I will attach pics of the wiring diagram and the actual wiring on the saw

[ElectriciansForums.net] HELP 3 phase masonary saw wiring

westward10 · Dec 18, 2018

I assume the refrigeration unit is not connected?

liambtuk · Dec 18, 2018

unsure as to what you mean there?

snowhead · Dec 18, 2018

Has it ever worked whilst in your ownership?
Has anyone worked on it lately, if so what were the symptoms leading to it being looked at?

You're probably going to need an electrician familiar with 3 phase motors to both test the motor and test the 3 phase supply to it.

I think Westward was refering to the drawing showing a Refigeration unit in the wiring.
Does that refer to a water pump for the blade?

westward10 · Dec 18, 2018

The unit which says BOMBA REFRIGERACION on your schematic is a cooling pump, is it there?

Strima · Dec 18, 2018

When was the motor last serviced?

Has it worked properly in the past?

Has it had any modifications?

Pete999 · Dec 18, 2018

Wired in Star, think what Westward means is, is the kit marked as Bomba refrigeracion is connected or not?

buzzlightyear · Dec 18, 2018

looking at the wiring in that motor the possibility is wired wrong to the board .

telectrix · Dec 18, 2018

and a pic of the rating plate would help

Pete999 · Dec 18, 2018

How are you starting this Motor? the entry of the wiring looks a bit suspect as well.

telectrix · Dec 18, 2018

i suspect someone has messed up the winding connections. those red, black, and whites just don't look right.

liambtuk · Dec 18, 2018

No there's isn't a refrigeration unit attached and yes I think it's a water pump but it isn't attached. The motor is around 3 months old we had to replace it and the last person to wire it up did it this way.
The wires coming into the saw are all fine and checked by an electrician.
The switch to start stop the motor doesn't dry on when pressed we've been having to keep the button pressed in to run it.
Attached pics of on off switch and plate

liambtuk · Dec 18, 2018

Pics

westward10 · Dec 18, 2018

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

Pete999 · Dec 18, 2018

westward10 said:
Sounds like you have lost a phase if so stop using it.

Judging from the photo you posted Siam, the wiring to the motor looks anything but fine, no glanded entry, looks a right DIY job to me, did the starter come with the Saw? As Westward noted maybe you have lost a phase, have your electrician check that possible fault out, your saw starter looks like DOL maybe you should consider Star / Delta set up, to avoid any start up difficulties.

snowhead · Dec 18, 2018

westward10 said:
Sounds like you have lost a phase if so stop using it.

Cause that's what probably killed the last motor.

liambtuk · Dec 18, 2018

Yes the starter was supplied with the motor from Sima

buzzlightyear · Dec 18, 2018

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

did he wire that motor up

telectrix · Dec 18, 2018

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 · Dec 18, 2018

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 · Dec 18, 2018

telectrix said:
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 · Dec 18, 2018

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

Strima · Dec 18, 2018

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

telectrix · Dec 18, 2018

Pete999 said:
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 · Dec 18, 2018

telectrix said:
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.

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