[cormacktimothy]

Hi all. First time asking a question. Most of the time I can find general answers that I can work with, but this is an electrical problem and I think I need something more specific.

We have a Laguna Smart Shop 1. There are two transformers (JBK5-800), stepping down from 220 to 130, running the z, x, and two y stepper motors. One of the transformers blew in the middle of a job (very light pocket cuts, so hardly any load) and blew the breaker too. I reset the breaker and tried to turn the machine back on. As soon as I switched on the main power the transformer immediately popped, sparked, and smoked while also blowing the breaker again. I called Laguna and they recommend replacing the transformers assuming it was due to the age of the transformers. I installed the new transformers and it did exactly the same thing.

Right now I'm trying to chase down a possibly compromised wire that's shorting out the system, but no luck so far. Any advice would be helpful. Am I barking up the wrong tree? Am I missing something obvious? Once I find the smoking gun are my new transformers useless now because they popped?

Thanks!

[kenrbass]

Disconnect the power wires from the drivers and see if it still pops the breaker. Could be a bad driver. If it doesn't trip breaker with all drivers disconnected, connect one at a time and try each time to see which one is the culprit. Always turn off all power before making changes to test.

[cormacktimothy]

Disconnect the power wires from the drivers and see if it still pops the breaker. Could be a bad driver. If it doesn't trip breaker with all drivers disconnected, connect one at a time and try each time to see which one is the culprit. Always turn off all power before making changes to test.

Thanks kenrbass! That's a great suggestion. I'll try that and let you know how it goes.

[cormacktimothy]

So interesting update. First I disconnected the power lines into the transformers. So, in theory, there shouldn't be any power going through the transformers. I turned the power on and the transformers still blow. Which means that power is backing up into the transformers from another source. I disconnected the power wires to the controllers (like kenrbass suggested) and nothing happened. I turn the power off, connected one controller at a time, and the transformer blows every time.

[kenrbass]

your last reply is not logical.

[cormacktimothy]

your last reply is not logical.

I agree. Imagine my surprise when the power in was disconnected but the transformer still blew.