Quote Originally Posted by OMLCNC View Post
From putting the meter over A1, A2 on the contactor and pressing the start button the voltage is not instant ie it climbs to 240v while it chatters,
same if you put it over any of the other contacts. When it pulls in it is 240v. So readings might be 50, 70, 130, 170 then 240v (all while chattering)

Is there a way of wiring out the braking board item 7 on the drawing and still making the machine work to eliminate it from being the problem?
I can disconnect wire 24 from the contactor to stop it breaking, but there are 5 other wires still connected.

Then I can happily spend the £500 knowing that that is the cause.
The readings are what I suspected you'd get, especially with a multimeter.
What about the input voltage to the transformer?
If they also drop, what about the main supply into the machine?


What I can't really make out from the wiring diagram, is are the top right wires, and lower left side wires on the braking module directly connected (I'm guessing each wire has a separate terminal, but are the terminals paired together? - A photo might help)

However, I think if you remove the link between R8 and 4 on the contactor, it'll be enough to break the circuit for the braking.
Do you have a diagram for the selector switch, as it would help understand exactly what's going on?

Assuming the selector switch is just a switch, with no relays/contactors to control things, then the key to the braking circuit is how the 3rd leg is handled. It is controlled via the auxiliary contact (other two legs go via the main contacts, with the third main contact used as the latch for the start button - the start button second contact also bypasses the aux. contact, which I assume also ensures the braking module remain inactive until the contactor is fully energised), but goes to the braking module, before heading to the selector switch, unlike the other two legs that go straight to the selector switch.
The braking module is also connected to the 2nd leg output from the contactor (terminal 4), via the NC contact (R8), so when the contactor is energised, the braking circuit is broken, but once the contactor is de-energised, the braking module is connected to the 2nd and 3rd legs on the motor side. By breaking the 4/R8 link, it should prevent the module from braking (which I'm assuming is done either via DC injection braking, or controlled shorting of the legs).