Myford super 7 lathe, tripping RCD

[Nick Clarke]

Hi, just bought a Myford Super 7 lather. It was working fine when I picked it up. I’ve installed it in my workshop and everytime I switch it on, using a Dewhurst switch, it trips the RCD. Everything else in the workshop works fine. Any ideas?

[Muzzer]

Step by step - disconnect the motor wiring (insulating them carefully) and see if the RCD still trips. If not, it suggests the motor insulation may be to blame. Was it being sored in a damp place?

Presumably it has a starter cap - you could disconnect that temporarily to see if it has broken down between the internals and the case.

It may have been working fine before you picked it up if the previous owner didn't have am RCD on his outlet.

Make sure the machine has a good solid protect earth connection back to the plug. If there is something dodgy going on, you should ensure that protection is dependable.