Build A Contactor/relay

[scraglor]

just use two two pole NO contactors and a little plug in relay to do the flipping and the flopping much cheaper than buying new

Edited November 19, 2011 by scraglor

[growguy yorks]

just use two two pole NO contactors and a little plug in relay to do the flipping and the flopping much cheaper than buying new

Ok, so that is ok to do for flipping bulbs? cool, that means I can get em pretty cheap. I presume one of these would be ok to switch between the 2 contactors-Ive used this before to switch fans in the climate controller you helped me with in 2008-the one that got nicked.

Also, Ive got a canatronics light, it has the ignitor mounted in the bulb holder housing to allow for long distances between ballast and bulb--could that arrangment be flip flopped, or is it a bridge too far?

Edited November 19, 2011 by growguy yorks

[growguy yorks]

Ok, ebay link not allowed---there was an ebay link in the last post where i say "one of these". it was a relay, i guess any 230 relay will do for the switching between 2 conactors

[4n7h0n9]

Hey scraglor thanks for all the information, I think Im starting to gain a better understanding of this subject now... Before reading your posts I thought I could just find out the start up current of the ballast and multiply it by the number of them to be used (eg. 4 x 600w = 4 x 3.25A = 13A)=(Single pole contactor rated @ 16A connected to a 4 gang trailing socket) If only it was that simple! So heres what I have learnt so far:

1/ The start up current means it is the capacitor which creates a huge inrush of current.

2/ Not all contactors are capable of switching HID lighting regardless of their ratings.

3/ Breaking 2 poles instead of 1 is not essential but makes the contactors job easier.

However I am still confused...

I want to make a contactor capable of swithing 8 x 600w please help!

[scraglor]

switching that much all in one go, then start up current is going to have an effect, both the inrush of the capacitors and the inrush of the inductor (the ignitor works by causing a larger than normal current to flow through the inductor) so you're gonna want to do it in stages. 4 at a time should be fine, the cheapest way would be to have 2 contactors, and two plug in timers and you'll need four sockets to plug into... the more expensive way is to have two plugs, one powering one bank of four, and the one the other bank of four, and you'll need either a two channel timer, where you can set the start times four each channel a few minutes apart, or a single channel timer, and use a delay timer to put a slight delay to the second contactor....

the latter will be much more expensive and complicated.. so i'd say just get two 25A merlin gerin ct 9's and basically just build two contactor units, but in one box

[scraglor]

growguy, the ignitor inthe hood shouldn't be a problem, and you can just use any old double throw relay to switch between the two contactors, just make sure the contactors you use have a high enough impulse withstand

[4n7h0n9]

scraglor... you are the man!

[growguy yorks]

Thanks again Scraglor,

I wonder how growrooms are out there, with kit built , either directly by someone you helped, or by someone who has been reading here.

Have a good one.

[Laphroaig]

Just wanted to say thank you to everyone who's contributed to this topic, have learnt more here about that nasty invisible stuff that kills you in the last couple of hours, whilst I've been wading through the 24 pages of posts struggling to comprehend what's going on with my tiny pea sized brain, than in ... well forever!

It's really galling starting up because there's nothing out there that really does the job the way you want it to, "I got a fan controller that makes my fan louder the slower it goes...WTF!!"etc. If you're anything like me if you're lucky you'll find a compromise where it works well enough for you to justify using it and the money you paid. However you just know that if you could figure out how to get that to do that and so forth it'd be so much better. Thanks to all of you I have seen the light, literally so to speak!

My initial investigations into the mystical nature of electricity began at age 9 when I became fascinated by the effect sticking bits of wire down the back of the TV had to the picture on the screen. Probably a wire coat hanger. Anyway after I regained conciousness I was determined to henceforth avoid the stuff at all costs and try to figure out how I was going to manage to dodge the blame for blowing up the TV set.

One question I prithee oh most knowledgeable ones before I depart. Should I, in my folly and foolishness, desire to switch the contactor with something other than an electronic plug in timer (may I forever burn in hell to even think such a perverse atrocity), say a wireless or traditional room thermostat for example (now you're really pushing it), would that influence the choice of contactor?

I'm thinking of a Schneider contactor, Multi 9 Merlin Gerin, CT2000, 230-240V AC, 40A, 4P+4NO Part No. 15968 to switch up to 4x 600w.

I will need to add some kind of delay timer to make sure the lights stay off for a couple of hours after the thermostat trips .... and this is where my head begins to hurt.. I think, Have to have delayed start, temperature drops below set limit and the thermostat send signal to switch on lights, I need to delay that so it's the Multi 9 Merlin Gerin RTA: delays closing Part: 16065 Description: Delays energization of a load.

There shouldn't be a delay when lights switch on at the beginning of each 12 hour period as the thermostat will activate the timer delay as soon as the temperature drops below the set limit which it will inevitably do at night.

I was thinking of plugging this into my tatty old timer board but now I'm this far it seems to make more sense to ditch it and put a timer on this new box and wire it directly to the supply in place of the old one, perhaps ever run a second identical contactor just from the clock so I can have half my lights on just on the timer and half timer/temperature controlled.

So use the clock to switch both contactors. On one add the time delay relay switched by the wireless room thermostat base receiver to one of the circuits between clock and contactors to interrupt supply if required. Each contactor outputs to a separate block of four sockets, Screwfix do a particularly nice model with individual power switches for each socket and a big red power on LED at the end, dunno if they are suitable if I just take the plugs off and rewire them.

Now I'm going to make a coffee and see if I can dream up a wiring diagram for this contraption.

Please tell me if I'm; (a)about to die horribly or (b)create a planet eating vortex that will ultimately lead to the destruction of the universe, ©ertifiable, (d)unintelligible (e)weird or all of the above.

OMG I'm so sorry for hijacking this perfectly innocent topic with my rambling insane contraption.. I got carried away on a flight of fancy, if anyone thinks this is remotely feasible I promise to start a whole new topic. Honest.

I must stop now before my head explodes! Will get my coloured crayons out and wire up this behemoth. brb

Peace

[Laphroaig]

Well this is it, must stress my level of electrical expertise is about competent to wire a plug but nothing else so all this is just from reading the the last 24 pages, prior to that I knew nothing.

After further investigation I'm going to take another look at thermostats as the one I looked at is apparently a bit fragile and temperamental.

Found a new 40A contactor on fleabay exactly the model I was after, currently bidding at £8.00.

RTA Relay is proving to be a bit of a pita, will be the most expensive part of the system if I have to go to a genuine distributor.

Could probably use a fuse some place.

Would love to know what you think? Please forgive my glaring ignorance in advance

[scraglor]

why do you want to switch the lights on with a thermostat??

and yes, you can use whatever, haven't looked at your diagram it's late

ok had a quick look, you want to turn your lights off if the room goes above the set temperature right?

i wouldn't bother with the delay timer, modern hps setups are instant hot restrike anyway, and if they aren't, the igniter just times out, then restarts after a built in delay... remember these lights are for flood lighting, and have to power up after power blips etc

don't really see why you want temperature to turn your lights off though, especially at this time of year, and a few hours after the thermostat trips is wildly out of need, the lamp cools down enough to restart normally after about 5 minutes if the igniter isn't man enough to restrike while hot

Edited November 25, 2011 by scraglor

[Laphroaig]

Hello,

Thanks for your response and woot that my pipe dream may be possible, keeping fingers crossed it survives closer scrutiny.

You are quite right it did start out as a cut-out for the lamps if ever the fans failed or something else happened that made it get excessively hot. Sorry a 13amp plug in timer was just too pedestrian for me.

I just got carried away after that, figured I'd need to run it through my existing crappy old board with bare wires sticking out of the top that scare me shit-less and would have to have a few 13amp plugs to take the load, at which point I declared bugger that and decided to get rid of the death-trap and slap a 24 hour timer on the front of this contraption.

So essentially now its a lighting controller with rudimentary temperature protection and incidental environmental control ... I actually have 9x 600's but it's way too much for my fan except in the depths of winter, 5-6 lamps is quite adequate for good results.

In my previous mutterings I mentioned getting a second identical contactor and just running that from just the same 24 hour timer as the first contactor would give 8 sockets switching a straight 12/12 and the other 8 sockets a combination of 12/12 timer and thermostat controlled. At which point I could rip that tatty old lighting controller out and use my new baby instead.

Now to the point about the delayed start. Typically I'll be running on 5 lamps running 12/12, the environment is very pleasant and easy to maintain around 22 Celsius that way. If I go away for a few days, for extra peace of mind you can guarantee I'd just swap them over to the other block of sockets so if anything does go wrong the thermostat will turn them off and I have a little less to worry about whilst I'm away. Stops the ebiegeebies creepin up behind you as you're 50 miles down the road, " did I turn that on, oh crap did I remember to shut the front door," (350 mile round trip and a full days work at the other end, came home found I'd left the front door wide open all day long, and it's a terrace, no front garden. Not a single thing touched, although it's a cliché. The people who did come to steal stuff probably took one look around and said to themselves "poor bugger" and did some washing up or something cos they felt so sorry for me.

Yeah so anyway RTA Delay Start Relay. Why I shall have one despite everything you say "my precioussss". Unless you can convince us that it is indeed the secret component that opens a Rosenberg portal bridge thingy to the other side where evil dwells. No? It doesn't! well then, that's exactly why I'll be needing one! Okay but seriously, I'm looking at 2-3 hour delay before the lights come back on once my upper limit, probably 27 Celsius is reached on the thermostat. Once the limit is met the circuit is broken and the lights go out, even turned off they radiate allot of heat so it will be a couple of minutes before the fan catches up and starts bringing the temperature down. As soon as it gets below 27 Celsius the thermostat closes the circuit and .... well if there was no delay you'd just be cycling through start ups every few minutes whilst the temperature fluctuated a few fractions of a degree either side of the set limit. I want the plants to have time to rest a while and the grow room temperature to go down by at least 3 degrees before the additional lights kick back in again. So I need a delay relay, ideally something that can handle long delays, up to 3 hours would be perfect for the summertime when cooling takes longer and heating is much faster. Also when things go belly-up switching your lights off for 5 minutes and constantly recycling won't save your crop from cooking. With a delay relay there would be spikes in temperature a couple of hours apart as the lights fired up, heated up and turned off for a couple of hours, there's a chance the plants will survive a day or so until you notice the issue. Without it just depends how well insulated and how well lit the grow room is as to what maximum temperature can be achieved, the heat will rise constantly over the 12 hours until the timer switches off the lamps by which time the plants look like boiled spinach and it's time to get the bin bags out.

So the delay relay stays. Trouble is I'm confused over this "Voltage Free" option when wiring up the Timer, Thermostat etc what should I choose that or "230v" and where does the delay relay get the power from to continue the delay count when the lights are out, think I should put it between A1 on the contactor and the neutral mains supply so it's never isolated.

Anyway to bed

G'nite to everyone

[scraglor]

you could just get a bigger fan plus a fan controller........

the timer has it's own separate power feed.

depending on what sort of timer it is, if it's a delay on (which is the most suitable) it doesnt need to time while the lights are off, it turns off when power to the lights is switched off via the thermostat, then when power is reapplied by the thermostat, it starts timing, once the timing is completed, it applies power to the lighting contactor bringing the lights back on

[Laphroaig]

Hiya,

Currently the exhaust from the room goes out up the chimney, use a 10" cabinet fan to shift it. Have tried 12" fan but sadly even the best of the acoustic cabinet fans I've tried are an order of magnitude louder than the 10" I have already, even with a couple of meters of insulated ducting between fan and the flue. I can run the 10" all day at max power and it is barely audible, the 12" has to have a stepped voltage controller to make it behave. So can't do a bigger fan sorry.

Have an Ecotechnics controller running the 10" at the moment, it runs the fan at full speed until it gets below 18 Celsius and then switches the fan off and turns on a heater. Given what it's supposed to be able to do and what after years of fiddling I've finally decided it can do adequately, it was a total rip off, get the same functionality on a room thermostat. However it has been good in one respect, now that I've gained an understanding of what makes it crap, I can design and make something better. That will be my next project after I get this monstrosity built.

Ahh figures, I couldn't see how the delayed starting timer would work without current going through the circuit. And never actually having seen one I guessed based on the information I had. If its wired up that way then it will only recycle when the power is on, which means when the 24 hour timer cuts the power to the rest of the circuit the delay countdown is suspended until the power switches back on.

I guess the only way to make the delay count recycle whilst lights are off and there's no power coming through is to use another circuit, oooh. Take the delay relay out of the diagram and replace it with a ordinary relay that is controlled by the new circuit. Use the Normally Open terminal on the thermostat to switch it and whey-hey Presto! Delays then set between light activations will be absolute irrespective of if there's current running to the lights or not.. this is kewl.

Cannot believe I didn't get into this shizzle at school, it's fascinating, must have been one of those late afternoon double periods in summer when falling asleep in Physics was inevitable. Doh!

Okay going to go away and get out the crayons again, I shall return.

Peace

[scraglor]

you don't need another circuit

when the room gets to hot, the thermostat turns the timer off, which in turn switches off the lights.... when the thermostat gets below the temperature again, it applies power to the timer, which prevents the lights turning back on for however long you set it, as you say you don't want the lights cycling on and off around the temperature setpoint, you want the room to have a good while to cool down after the room temp decreases back below the thermostat setpoint, this is what the timer is doing

once the thermostat goes below the setpoint after the lights turn off, it turns the timer on. the timer times out then turns the lights on, no need for a separate circuit or another relay....