3 phase motor

[Duncan Bennett]

No problem, Archy.

I'm actually quite pleased with the way this has gone; i know i don't know much about three phase, but I feel vindicated when I see how interesting this thread has actually become and, if a guy like Tony can be slightly taken aback by the spec. of the motor, then how baffled was I going to be - justification enough for having made the post in the first place :0)

 

[Lilley]

i would use a C10 triple pole. C type to reduce tripping on start up

 

[Darkwood]

Tony I'm no expert on motors.

But you are right the 6.4A rating for a 2.2KW 3P motor is for a delta connected 230V supply.

For Star connected, 400v 3P 2.2KW motor the current will be 3.19A.

So a 6A c-type breaker will suffice with 1.5mm cable.

Check out my posts regarding mcb sizing for this motor, you'll be supprised and hes already shown plate in pic as 6.4amps.

 

[Knobhead]

Tony I'm no expert on motors.

But you are right the 6.4A rating for a 2.2KW 3P motor is for a delta connected 230V supply.

For Star connected, 400v 3P 2.2KW motor the current will be 3.19A.

So a 6A c-type breaker will suffice with 1.5mm cable.

You have to take power factor and efficiency in to account as well.

 

[Darkwood]

Quick question duncan... is the 1.5mm SY the supply from the mains or is it the cable linking motor up to control box?

 

[netblindpaul]

I suspect that is the "machine" rating plate, not just the motor?
It may have solenoid latches that are part of that current draw.

 

[Duncan Bennett]

Duncan note on your second pic.... SY cable has been utilised to supply motor... but i see the screen has been taped off, make sure you earth the screen as its a possibility if the cable is damage it may become live otherwise, and Note! on my mcb choice, alot of people question why i have picked mcb's alot higher than expected, i cross reference them to manu' guides of mcb's and recommended mcb in relation to motor size.... having said that a 2.2Kw would normally need a 16amp(b) or a 10amp(c); In your case the motor current FLC (full load current) is that of a 3Kw motor hence i have thus given the mcb rating for a 3Kw motor. Following this advice you will eliminate periodic nuisance trips due to inrush.

Yes on the sheath. In fact, there are no glands on the SY cable at all, at both ends it is taped off and pushed through a rubber grommet at both the control switch and isolator. I have them on my shopping list.

Thanks

 

[Darkwood]

I suspect that is the "machine" rating plate, not just the motor?
It may have solenoid latches that are part of that current draw.

Well spotted .... missed that one as it has the weight on it and by heck that one heavy motor, this changes everything if thats the case as the motor is prob 2.2kw standard thus a 16(b) or 10(c) will suffice.

 

[Darkwood]

So now we seem to have all the info duncan and as netblind has spotted; you have be giving us misguiding info and this power rating is the total ramp and not the motor rating itself, in this case then we can guess the motor is a 2.2kw and is standard ampage of 4.8amps.
So a 10amp (c) mcb , the SY will need earthed braiding too and your good to go.

 

[Duncan Bennett]

So now we seem to have all the info duncan and as netblind has spotted; you have be giving us misguiding info and this power rating is the total ramp and not the motor rating itself, in this case then we can guess the motor is a 2.2kw and is standard ampage of 4.8amps.
So a 10amp (c) mcb , the SY will need earthed braiding too and your good to go.

Sorry about that, it was all the info I had. Thanks again for all your help with this