How an incandescent light and a ESR meter ** friend**have a machine blowing fuses

[sam_sam_sam]

About a month ago we had a transformer jumper wire that burned in two different places between two transformers caused over $200 thousand dollars worth of damage to VFD drives at least 10 of them and a memory card and quite a few power supply as well

Now we have most of the equipment that got damaged back up and running except a feeder that has issues and we are waiting for some parts for

Now we also have another piece of equipment that was blowing fuses on the 110 volt controller switch circuit with the “E” stops and one switching power (24 volt) supply and a transformer power supply ( 5 volt power supply )

Well this where it gets a little bit hairy with the maintenance/technician that I work with because they just kept putting fuses in it and getting the same exact results simply because they do not understand how to troubleshoot a situation where you keep blowing fuses and these fuses are not cheap around $20.00 each

I told my boss that the only way you are going to get anywhere with this price of equipment is to remove one wire at a time until you find the wire that has the short on it with a Ohm meter and a ESR meter to know what the actual resistance is not what the multi meter is telling you

Now my boss understood this concept because he had done this in the automotive mechanic and done this before as well but had not done this with a piece of equipment with a 110 volt control circuit which I have done this several times before in the past

It turns out that the gas valve / flame detector controller has a dead short 2.3 ESR reading that reading told me more than the multi meter was telling me
I have use this combination before on another machine where I used to work at that was blowing fuses as well

Once I removed the wire from the gas valve / flame detector controller and reconnected the power supply with the incandescent light bulb instead of the fuse the light bulb was only dim ( because before the light bulb was as bright as it would be plugged into an outlet) and the machine controller came back to life and I do not know if anything else is wrong with this machine tomorrow is another day

This one big reason why using an incandescent light is definitely your friend in situation like this

I hope this helps someone else that finds themselves in a similar situation and use this method of troubleshooting because it might help you from going down a deep rabbit hole that just doesn't make no sense about what is going on

[sam_sam_sam]

How an incandescent light bulb and a ESR meter is your friend when you have a machine blowing fuses on the 120 volt control circuit

For some reason it would not let me post this that is above and it is not allowing me to correct spelling errors either if go back and hit edit I can see it but for some reason when you hit save it did not save it I had to make another post

Now my boss has use this method of using an incandescent light bulb to troubleshoot a problem with blowing fuses in a automotive type of setting but had never done it in a machine type setting before but he let me have at it because his boss was getting a little inpatient with this machine being down

Luckily the manufacturer of this equipment made it easy to figure out where the 120 AC volt section is located because all the wires are red the 24 volts DC are blue and I think if I remember right the 5 volt DC are gray one note we do not have the right wiring diagram for the model number that we have because apparently the serial number matters on this machine to get the right one

Unfortunately the wiring diagram does not show the wire number which is really shit-ie which is why you can not know where a wire goes unless you physically chase it from one end to the other end really are you kidding me this does not make your life or job easier by no means

Update we got the piece of equipment repaired today and we are back in business with this nightmare

Now we have another nightmare with another piece of equipment that I think has a bad IO card in the PLC because the fault light is ON for the IO cards but I think we narrow it down to which card is because of what is not working correctly

Update on the feeder it appear to have a bad safety relay and who knows what else is wrong this equipment but unfortunately we do not have one on the shelf at the moment

One note some of the equipment are 20 years or older and we do have some equipment that is a lot newer but the older ones are ones that are nightmares because they have been around so long that they really need to be retired and put out of their misery and mine as well