Transient relays/ Under Voltage relays

[Guest 004]

Has anybody had any dealings with these?

I have been asked to test an Under Voltage device, which I think is a transient devise as well (guessing) as it has +-10%

A single control fuse is blowing repeatedly, and my assumption is that everything is ok untill the monitoring device is switchrd, which then puts out a fault on the output side, which in turn goes through relay, which pulls in the coil on the contactor, and somewhere it blows the fuse.

Any ideas suggestions? Really need to know if this in fact a transient device or not, or just Under Voltage.

 

[Darkwood]

Take a pic and post... or details on device which I suspect is something else +/- ?% is usually found on numerous devices indicating output voltages, input tolerances etc etc.... may I also stress that your query indicates you are delving into things you are not experienced in and with it been some kind of control circuit I would recommend you don't attempt this yourself as even a simple mistake in replacement or fixing of the fault may be a safety hazard that might not show up until its too late.

 

[Guest 004]

Here is the picture

Supply comes in top right, feeds the 3 mcb's in the middle, to right of them is surge arrestors. From the 3 MCBs supply goes out to the supply side of the contactors, then loops out to 3 control fuses on the left hand side. One of which keeps blowing. The control fuses feed the Under Voltage monitors (Transients devices?) on the right hand side, so when the voltage drops or spikes, they switch the relays to the left, which in turn will drop the supply to the coil to the contactor.

I do understand all of that, so thinking faulty 'monitor' Under Voltage? or faulty relay, or maybe a crossed connection on the output side. The system is up and running, and this fault only occurs when the under voltage monitors kick in.

I have not been to site yet.

 

[Guest 004]

Please ignore the colours of the wiring.

Just keep things technical please.

What I am really asking is what are the 3 devices with the digital display 'On' on them. Now obviously they are just switching the relay, but could they be transient protectors? or just Under Voltage protectors or both.

Thank you

 

[Darkwood]

If the device you refer to is the red 3PH/N block I wouldn't worry too much as there is a spare one at the bottom of the panel in its rapper still, its hard to make out but was after a close up pic of the suspect device, and if you have yet to go to site there isn't a lot we can do here as the device could be shutting down on an output fault and just doing its job.... too many variables at the moment. ................edit just read last post and now know its the 3 devices at the bottom right...get close up of name and product code and all will be revealed as im not familiar with this exact brand but could be one of many devices.

 

[Guest 004]

No that's the surge arrestors. Its the 3 devices below with the digital display in red 'on'

what are they?

 

[Darkwood]

Just by query what is this panel controlling they could be monitoring devices looking at an external sensor etc ?

 

[Darkwood]

Ps cant tell need closer pic as I don't recognise them afar but could be one of many things .... need close up of one with brand and product code then google will do the rest .... once we identify them then we can make suggestions if you still need us to.

 

[Guest 004]

Goes to UPS, so when the voltages differ by more than 10% the UPS kicks in. Thats what I am told, but will need to confirm once I get to site.

 

[Darkwood]

Now its starting to make sense .... the info is flooding in now.... so on that note I would guess its supplying 3no' UPS 1ph units.... 1per contactor and yes they are most likely to be voltage monitors of some nature, check the wiring plan on the side of the unit and see if contactor coil supply is common to the monitor device ..if this is so its more likely to be a contactor coil fault ..... disconnect the affected UPS off the contactor and try without load to ensure the fault isn't the UPS but without knowing too much more this is all a shot in the dark... you have everything in triplicate so simply swapping 2 items around can eliminate if its faulty or not.

 

[Guest 004]

yeah my thinking.

Thanks thats a real help

 

[Guest 004]

Just been told it is 3 invertors

 

[Darkwood]

All I can suggest then if no info present either use tintenet onsite or smartphone and browse the destruction manual then take it from there.... its a setup you have that I haven't come across but a hour on site and some head scratching should see you isolating the fault or sourcing it anyway ... it looks a basic set-up so just take it section by section and testing for faults but yep you confirmed 3 circuits in triplicate as I guessed, so 2/3rds of the controls isn't part of the issue.