Contactor problem

[ProDave]

It's not a case of being unhelpful.  You have a contactor and a timer relay wired somehow and it does not work as expected. None of us know how it is wired without seeing it and how it is supposed to work. So you need to look and find that out.

 

[Rrrrr]

I'm not sure what the problem can be without testing it but my comment would be that it seems a bit of a naff setup for a plant room.

In the middle of replacing a pump the lights go out and you have to scramble across a dark room with tools on the floor to reset the lights?

Sounds a bit dangerous 

 

[Andy™]

of course, the simple solution would be to have PIR's on the lights instead of having to constantly find & press a switch...

 

[bluetobits]

of course, the simple solution would be to have PIR's on the lights instead of having to constantly find & press a switch...

Sounds to me like that's already the case... Interruption of supply, switches the PIR, energises the coil for a few seconds then goes of. Or maybe I've missed a post somewhere 

 

[Andy™]

i read it as light switches triggering timed contactor, not PIR's which are usually connected directly to the light SL

 

[Rrrrr]

I'm assuming push to make retractive switches pulling in a timed contactor

 

[Leejohnson222]

thats what you asked us in post 1

And I am admitting this was a ridiculous thing to post.

I'm assuming push to make retractive switches pulling in a timed contactor

Exactly  retractive centre off bias,the plant room is 20 years old and it is bad design, especially if people are working on Ahu or pumps as you say.

 

[Andy™]

I'm assuming push to make retractive switches pulling in a timed contactor

could well be. and if one of those is faulty and permanently closed...

 

[phil d]

I've seen this system before, although they were push to make switches, they connect in parallel to apply power to a timer relay, the switch triggers the relay which applies power to the contactor for anything for a few seconds to a few hours depending on the timer type. If it wont trigger and pull the contactor in when you press the switch then my guess is the relay is wired incorrectly, or has been replaced with the wrong type. As I'm sure a lot of us know these can be triggered by voltage applied or voltage removed, now if the switches were normally open type then the trigger will be voltage applied, if normally closed they'd be voltage removed. my best guess is he's got power going to a relay that should have power removed to trigger it, hence why it powers up when he removes power. If it was a volts removed to trigger and he had the wrong switch then this could cause the problem he's having.

what area are you in?

 

[Andy™]

I've seen this system before, although they were push to make switches, they connect in parallel to apply power to a timer relay, the switch triggers the relay which applies power to the contactor for anything for a few seconds to a few hours depending on the timer type. If it wont trigger and pull the contactor in when you press the switch then my guess is the relay is wired incorrectly, or has been replaced with the wrong type. As I'm sure a lot of us know these can be triggered by voltage applied or voltage removed, now if the switches were normally open type then the trigger will be voltage applied, if normally closed they'd be voltage removed. my best guess is he's got power going to a relay that should have power removed to trigger it, hence why it powers up when he removes power. If it was a volts removed to trigger and he had the wrong switch then this could cause the problem he's having.

not quote the fault i was thinking above, but without much to actually go on, it could be almost anything

 

[Rrrrr]

I think it is the contactor by the way it is pulling in when resetting the power but I would look at redesigning the system to make it more user safe

 

[kerching]

I would not be happy working in a plant room when the lights could go off at any moment!

just saying

 

[Lurch]

I would not be happy working in a plant room when the lights could go off at any moment!

It's a scam. They sell head torches at the sites gift shop!

 

[Andy™]

I would not be happy working in a plant room when the lights could go off at any moment!

just saying

but the lights need to go on and off in a plant room to make them grow

 

[Phoenix]

Not that kind of plant....

However it does remind me of the story about an admin lass we had in our office, happened to glance at the plans for a big posh house that was being tendered for, you know the type, 6 million bedrooms, gym, swimming pool, sauna, that type of thing.( Probbaly similar to what pro-dave is building in scotland for the same price it costs for a 2 bed semi in England .......)

Anyway, she remarked "How nice, they have a plant room". It had to be explained that it was not a room full of exotic houseplants were the owner could go and take 20 minutes to unwind after a stressfull day, and the reality was rather more dull!.  And yes Andy, I am sure she wasn't picturing *that* particular plant!

 

[Tony S]

I think it is the contactor by the way it is pulling in when resetting the power but I would look at redesigning the system to make it more user safe

Post a photograph.

Some lighting contactors can be latch ON/OFF

 

[Phoenix]

Post a photograph.

Some lighting contactors can be latch ON/OFF

Never seen a latching contactor, seen latching relays though, so appreiciate that it is more than possible for them to exist.

Just assumed if you wanted the latching functionally you'd use a latching relay to control a standard contactor, or just use a standard contactor and use a spare pole to latch akin to DOL.

Can see the advantage though if its a lighting board in an office and the staff complain about the 50hz hum

EDIT:

You didn't send a picture to the daily mail letters page recently by any chance, did you, Tony?

 

[Tony S]

You didn't send a picture to the daily mail letters page recently by any chance, did you, Tony?

? ? ? ?

 

[Phoenix]

? ? ? ?

I cant find the link now. But there was a picture in here of a cabinet with a sign that said something like "Opening this cabinet will result in certain death and a large fine" . Hadn't seen it anywhere else, other than a month or so ago it popped up in the daily mails 'picture this' section on the letter page, sent in by a chap called Tony

 

[Andy™]

i think that pic may have been posted on here recently