Multico Planer - 3-phase or single phase?

Finlay · 5 Jun 2014

Hi

I read with great interest a thread on here about wiring a Multico 3-phase planer and this prompted me to post this question of my own.

Some time back I bought a Multico SL91 Planer from a school. The planer was sold in working order but had been decommissioned by the school and was not connected to a power supply, so I had to take it on trust. A few wires were hanging inside it but all external wiring was gone.

The machine was sold to me as a 3-phase machine, which suited me as I have a 3-phase power supply in my barn.

However, when I came to unpack the unit in order to install it, I began to doubt that it was actually 3-phase. Although there was a proper 3-phase power switch box (empty of any wiring though) bolted to the side of the machine, the internal supply wiring INTO a key-operated on/off switch looked like bodged 3-phase cable changed to monophase (an earth, a single brown wire and another brown wire wrapped with black insulating tape to suggest a neutral. The final brown wire had been snipped off).

When I took the cover off the connection box on the motor it also seemed to suggest monophase, since the supply wire FROM the key-operated on/off switch contained a green, a red and a black.

I am going to try and attach photos of: 1) the wiring supply as it enters the motor, 2) the plate on the motor itself, 3) the motor itself.

If anyone could help me identify the supply type I'd be very grateful. I have no intention of beginning a rewire until I'm sure. Although this was sold as a 3-phase machine, the existing wiring is causing me a lot of doubt and I'd be grateful for some help.

Thanks in advance

Finlay

nathandavies · 5 Jun 2014

I know nothing about the electrics of machines but the motor plate states it is single phase 240v

Finlay · 5 Jun 2014

Thanks for that. I thought that too but I'm doubting myself because the machine was sold as 3-phase and has an (empty) 3-phase power supply switch bolted to the outside. I'd love to get an opinion from an electrical expert. I saw that some had posted on another thread and I'm hopeful that they might chip in here.

wizard · 5 Jun 2014

The motor is single phase a 3 phase switch can be used on a single phase motor if it has a 240v coil

Finlay · 6 Jun 2014

Thanks. Do you mean a 240v coil in the switch or in the motor itself?

deema · 6 Jun 2014

The motor is plated as being single phase, 240v. Most switches have poles to switch 3 phases in machines. However, a switch will be rated as either single phase, or 3 phase. Both are actually switching 240v on each live feed. The difference is that less current is required per live lead for a 3 phase motor of the same HP or KW rating as a single phase. In other words you need a higher rated switch for a single phase 2HP motor a than you do for a 3ph motor of the same power.

The motor is a 2HP, and needs maximum feed of 10.6 amps according to the motors plate. The switch must have a rating per pole equal to or above 10.6 amp. If it has your Ok. The switch should have a label on it probably inside the case that tells you what the rating per pole is. If in any doubt, change the switch.

I would personally always change the switch if its 'old' for a relay type switch with thermal overload. This will protect your motor from burning out and potentially catching fire. Any good electrical outlet of industrial switches if you show them the motor plate will be able to provide you with a suitable switch.