Help wiring a 3phase motor

[meerkat]

Hi Guys

Can anyone give me some "off the record" help to temporarily wire in a piece of industrial equipment with a 7hp 3 phase motor?

I am taking delivery of a secondhand rubber rolling mill into my storage barn to later resell it, I want to check it runs ok first

The barn has a new 3phase db without any mcb's fitted. My intention was to fit a 32A C grade mcb and wire to a 32A socket with 4mm^2 singles that I would then plug the rubber mill into. I guess I should have an rcd but they seem bloomin expensive for a temporary connection.

Am I on the right track?

Any guidance greatly appreciated

meerkat

 

[Guest123]

Hi there.

7hp equates to roughly 13A @ 400V. Obviously there is the PF to take into consideration also.

As a quick temp test run, I would try a 20A C type MCB rather than 32A.

 

[boatnik1]

Hi Guys

Can anyone give me some "off the record" help to temporarily wire in a piece of industrial equipment with a 7hp 3 phase motor?

I am taking delivery of a secondhand rubber rolling mill into my storage barn to later resell it, I want to check it runs ok first

The barn has a new 3phase db without any mcb's fitted. My intention was to fit a 32A C grade mcb and wire to a 32A socket with 4mm^2 singles that I would then plug the rubber mill into. I guess I should have an rcd but they seem bloomin expensive for a temporary connection.

Am I on the right track?

Any guidance greatly appreciated

meerkat

You don't mention if there is a starter/contactor/isolator on this machine. Not a good idea to just shove a plug into a socket to start the thing as arcing is possible in the socket as you push the plug in which can stop you pulling the plug back out.
Using the MCB as a switching device is not recommended either.
A contactor is the way to go but an isolator switch could, but ideally shouldn't be used as a switch to start the motor.
Is the motor plate marked star delta for start and run or star delta dual voltage.?
Either way make sure it is connected star to start it.

 

[meerkat]

Thank you Boatnik,

The machine looks like it has a contactor set but I haven't seen up close yet to be able to see what, if anything, is on the motor plate. I guess if I'm just making a connection to the control box containing the switch gear I don't have to worry about the motor connections? As far as I know it is in the same condition as when it was working at it's previous owner

 

[Bul76]

Thank you Boatnik,

The machine looks like it has a contactor set but I haven't seen up close yet to be able to see what, if anything, is on the motor plate. I guess if I'm just making a connection to the control box containing the switch gear I don't have to worry about the motor connections? As far as I know it is in the same condition as when it was working at it's previous owner

Hi,

Might be in the same condition but you never know. Should check out the connections just incase. Verify that the motor is connected in Star/Wye. You need to calrify the control circuit and also the power circuit connections. Verify your overload settings as per the motor name plate. Do continunity check of the control circuit, thus to ensure everything is functioning and wired correctly.
Never assume anything....

 

[meerkat]

Looks like I'm going to be busy!!