General Electric DC300 Drive Failure

I would start by ohming out the field coils. just a guess.

Thanks you for your reply

We have checked the field coil and it is fine

Thanks you for your reply

It's a drive that has been in service, then a time out service and now we need to put it into service again

We have not checked field parameters but de field current measured with dc amperometic clamp is zero

We checked the 3 diodes of 2/3 rectifier, the thiristor and it's fine

Yes, you noted that the SCRs are not firing. I forget where the gate pulses for the SCRs come from. Do you have the DC300 basic manual? About 3/4” thick?

You should have no voltage on the field leads, the manual shows what the scope traces should look like.

We put an scope on thiristor gate and there seems to be nothing, althoug with doubts

There is a resistor on pulse transformer primary coil circuit that heats up until it becomes incandescent in 30 seconds or so

We turned off the equipment for this reason

We have DC300 basic manual

Oooh, that’s a good sign, at least to point you in the right direction.

I would replace the power supply card, and set up the little trim pots according to the manual.

Thanks you for your reply

We are waiting for a new power supply card

We bought a card that we hope it arrives in a week

Then I will write back to report that it is working properly o continues to have problems

We have the new Power Supply Card and we put it in machine

and it continues to fail, same fail, FL04 Field Loss

We have checked all the parameters and they are in accordance with those

indicated in the manual for our machine

Now we are going to use the option to generate the field current externally

modifying the parameter indicate by manual for this way so that it ignores

the field current.

We will see if this method can make the drive operational

Thanks You