I recently was given a old Warco Milling machine in fantastic condition. I installed this into my workshop, (alongside my Myford super 7) plugged it in, switched on, and pludged the garage into darkness! The RCD tripped.
I have tested the motor and all its wiring with an earth leakage tester: no problems there. So I had a look at the switch on the side of the mill. The contcs were pitted, so I cleened them up, and tryied again. Mill ran ok a few times but then tripped the RCD again. So perhas (I thought) it could be this old switch that caused an imbalance and the rcd tripped. So anyway, I thought I would get a propper motor starter with an NVR switch from where I work, as they use 2kW+ motors etc. By the way the mill motor is a 4 pole, 1/2 hp unit with a capacitor start and centrifugal switch. So anyway, all wired up and switched her on, RCD tripped as usual! I do not know what to do now, apart from replacing the motor, or is it the RCD? Its a Contactum 40A 30mA - B4003/2.