Circuit breaker rating for electric motor

[Charles1948]

Could a knowledgeable spark advise me please. I am converting a 3 phase pillar drill to single phase. In the interests of safety I want to fit a cut out switch on the machine. I should mention that I have single phase motor with a capacitor start for the drill; the motor is 3/4 HP, 1425 RPM, Max output 5.2 Amps. I went to my local wholesaler for a switch and was sold a separate red button switch, a separate green button switch and a metal enclosure, as there were only two terminals in each switch I not work out how to wire them, so I contacted the switch technical people who said that as power would still be on to the drill when switched off it was not safe but he would not advise further due to regs, I assumed he was trying to say that I needed a double pole switch. I went back to the wholesaler who sold me a motor circuit breaker and enclosure, it is 3 phase with a rating of 6-10 Amps, the wholesaler assured me that I could loop the live lead through both the live terminals to make it work on single phase, this seems plausible, but I would like to know whether I need a circuit breaker that sets to 5.2 Amps or will the 6 Amp setting be OK. Thanks

 

[bernardgreen]

The only way seperate switchs can be used for this is with the assistance of a contactor with an auxillary contact to enable it to latch ON when the green button is pressed. The red button break the power when pressed and the contactor drops out ( turns OFF )

Mechanically interlocked RED and GREEN buttons can work without a contactor as they are just an ON / OFF switch that is easy to turn OFF.

 

[Charles1948]

Thanks Bernard, so therefore I am much better off with the circuit breaker switch, which I think must be safer and easier to wire in, but what should the Amp setting be on the circuit breaker (it is adjustable), should it be the same as the motor rating or higher to take account of surges, perhaps on start up?

Charles