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Swarfing
27-12-2010, 01:19 PM
Guys

I'm just doing a single to 3 phase conversion on a lathe and just ordered a 3HP (2.2kw) phase inverter for it. I'm have to redo all the electrics completely and want to add a contactor and mcb fuses (replace the old ceramic bulb type). When i did my mill conversion i changed the motor to a single phase motor and reused the existing contactor without much thought. The question is should i rate the contactor at the fuseable value of the inverter (25amp) or go much higher?

Cheers

M250cnc
27-12-2010, 02:44 PM
The question is should i rate the contactor at the fuseable value of the inverter (25amp) or go much higher?

Cheers

That seems to be too high, i have a rotary inverter 5HP that is rated at 25amps

Phil

Swarfing
27-12-2010, 03:26 PM
Have a look at the manual here.

https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/WEG-CFW10-0100-S-2024-EFACPZ-230V-2200W/default.aspx

This is the unit i have ordered

Swarfing
27-12-2010, 03:27 PM
it actually says 22amp on page 108

irving2008
27-12-2010, 05:46 PM
When you say contactor, do you mean independently of the MCB, which should be 25A. If so the contactor needs to be rated for 25A switching, not carrying..

Swarfing
27-12-2010, 07:58 PM
Yes Irving i do