wiring up dewhirst switch on lathe

[taycat]

struggling with wiring up the dewhirst type switch that came with my southbend.
can find pics of ones with 4 terminals either and 4 wires from motor.
but mine as 3 terminals either side and 3 wires from motor.
wires connected in pic were there when i got it so not sure if right.

3 wires from motor are brown, blue and earth.

 

[rtbcomp]

Sounds like you've got a single phase motor with no reverse.

It should be easy enough to identify 2 pairs of terminals that are both open when the switch is off or set to reverse and both closed when the switch is set to forward.

If so then connect the mains live & neutral to one end of each pair and the motor to the other.

If you can't do that then wire it as a single pole switch in the live side. There must be at least one set of contacts that are open in the off position and closed in the forward.

Don't forget to earth the frame of the switch.

 

[taycat]

if i turn to on top 2 on left side and top on right connect and bottom 2 on right and bottom on left connect
turn to off and they swap over.
so can i assume brown wire is in right place being on middle terminal and blue needs to be middle on opposite side?
sorry for qs but mains scares me after watching uncle go flying across room as kid.

 

[rtbcomp]

It's difficult to tell without having the switch in hand. What I did with mine was to draw up a table of what connected to where for each position.

Test it out with a meter before connecting it to the mains, you must avoid connecting the live & neutral together.

 

[rikrobson]

I suspect that the motot connectors go on the miggle ones. The live and neutral on opposite cornes and the start capacitor maybe on the remaining corners