Any Electrical Engineers around?

[RYH64E]

spikeyhead said:

Try them either end of each cable

Every cable? There are loads of them!

[rossw46]

rossw46 said:

Is the supply into the controller 3 phase ?

You say 3 phase supply to two sockets. The sockets must then surely be single phase, which is then supplied to the motor controller ?

[RYH64E]

rossw46 said:

You say 3 phase supply to two sockets. The sockets must then surely be single phase, which is then supplied to the motor controller ?

It's a 3 phase supply and a 3 phase motor, but the inverter is 220v single phase. Apparently that's usual, I don't know.

[anonymous-user]

Looks like std cable has been used, rather than Shielded cable!

Get some proper 3phase shielded cable, and connect the shield to the inverter earth/chassis terminal (only connect one end of the shield)!

[rossw46]

RYH64E said:

rossw46 said:

You say 3 phase supply to two sockets. The sockets must then surely be single phase, which is then supplied to the motor controller ?

It's a 3 phase supply and a 3 phase motor, but the inverter is 220v single phase. Apparently that's usual, I don't know.

That manufacturer does make a variant that takes a 3 phase input, but yes, yours most certainly only wants a single phase + neutral input at 220V. Do you know if both of your controllers are fed off of the same phase, or different phases ?

[RYH64E]

Max_Torque said:

Looks like std cable has been used, rather than Shielded cable!

Get some proper 3phase shielded cable, and connect the shield to the inverter earth/chassis terminal (only connect one end of the shield)!

The main 3 phase cable feeding the machine is armoured (I think that's the term) with a heavy woven steel shround around the individual cables, the shround is earthed to the machine body.

[RYH64E]

rossw46 said:

Do you know if both of your controllers are fed off of the same phase, or different phases ?

The electrician who did the install tried different phases but it made no difference.

[rossw46]

Which terminals are the other 2 wires at the top connected to ?

[RYH64E]

rossw46 said:

Which terminals are the other 2 wires at the top connected to ?

Which wires?

[rossw46]

The black one, and the green / yellow, looks as though theyre connected into the control terminals above the main terminals ?

[RYH64E]

I'll have a look tomorrow.

[RYH64E]

I'll have a look tomorrow.

[blitzracing]

Just a thought from College 20 years ago.....- could you be getting a phase shift between the current and voltage wave forms when the second motor is switched in? I know this is an issue with inductive loads, and you have to compensate by adding capacitance across the motor that has the opposite affect to get them back in phase again. There was a similar trick used by some to slow your electricity meter down, by forcing a phase shift between voltage and current so the overall power reading is lower. It certainly screws up the mains wave forms.

[jeebus]

Going off the pictures and info so far I would guess that you are getting harmonics down the neutral which is causing the other one to misbehave, Inverters like to do funny things to the sine wave of the supply which can sometimes cause unusual problems.

I would say you need a separate supply from the distribution board to each machine, also make sure that the inverter has been commissioned correctly to the motor, we sometimes get pumps that ramp up and down of their own accord at work when the motors are replaced with a slightly different spec one.