Recent content by GTC

Thanks Tom. You are likely on the money given that the other components seem to check out and the resistors have clearly been running hot at some period of the hoist's life. I won't get access to the hoist again until the weekend. If push comes to shove I can probably find out the original...

Yet again, there are no "internal parts not shown". What I have sketched is exactly what is on that board. There is nothing mysterious about the relay itself. It's simply a common or garden SPDT (Form C) with a 220 volt coil. It matters to me how the circuit works, which is why I created...

@Averagesupernova: explain the theory of operation of that circuit to me.

There are no internal components. The hand drawn diagram I provided shows exactly what is on that board. As I said earlier, I have already flipped the phases. Whatever is triggering that relay to operate has nothing to with phase connections. Doesn't change the fault situation. The...

Yes, and before I proceed I want to know how that circuit works, hence this thread. Have done that. As per my post #4 "The 39k resistors still measure a tad less than 39k." Yep, and the solder joints are still in very good condition. Tested all of that already. Again, my question is how...

Frankly, I find the personal tone of the above offensive. No it doesn't. My question is how does that relay circuit work. So far, no one has answered that question.

The original socket is fine and being used for a temporary replacement hoist. The hoist in question was operating fine until it suddenly stopped working, so whatever the cause it appears to be related to the relay in question.

It is being tested within the workshop -- where it normally lives hanging above a CNC machine -- but is now on a bench for this purpose and is plugged into a different socket. I could try swapping around the phase connections, although I don't see how this relay circuit could detect a phase...

I have been given an electrical chain hoist to repair. The symptom is that it suddenly stopped working. I have checked the motor's windings and they each show similar DC resistance of 0.0018 ohms. I have attached the schematic (dunno why it was rotated 90 degrees during the upload). The hoist...