Starter fault.

[Tim Nott]

I have a 3-phase Startrite bandsaw. The other night, around 11 pm, the lights went out. The next day, I checked what caused the switch to trip - it was the bandsaw. Unplugging it solved the problem, temporarily. It can only be the starter - I've checked the cables and plug - and there's a bang and a flash within the starter box when I plug the machine in. Anyone any ideas why it should suddenly fail in an unattended workshop?

 

[Myfordman]

If the bang/flash occurs in the starter before you even press a start button then there is a wiring fault on the input side as nothing else should be connected.
It is just possible that the part of the control circuits related to the safety switches and associated wiring is on the live side and is faulty.
Just a case of crawling through the wiring looking for faults such as chafed insulation etc. Be methodical and take photos before disconnecting any wires etc so you can put them back where they belong.
Good Luck