Would a 30A spdt power relay product code N24AW & N19AW from maplins be suitable for a 600hps relay?

It looks pretty hopeful - 9KW resistive - one would hope it would take 600 watts inductive.
I would go for it.
Best wait for a proper electical expert though.

Cheers! Thought so will wait for confo!

i'd go for a proper contactor , they can be bought on a popular auction site for around a similar price ,or from a miriad of online suppliers, maybe a fiver more, & well worth the extra for the peace of mind.
afaik, the contact material is far superior on a contactor designed for the job , rather than a relay
Get it sent to a different address from the grow if poss.

Dont have access to order off the net! Dont have allot of income either has to be D.I.Y for now im afraid!

no electrical wholesalers in your area?
you may get one for a tenner -ish . and as i said worth saving for a week or 2 , in the meantime if you're able to be there at lights out and lights on, you could do it manually till you can get a contactor .( it's gonna be a diy job with a relay or a contactor )
it'd probably be slightly better using a craplin relay than blowing up a couple of timers ( or your grow !) if using them on their own. but seriously , save up if poss .
it'll be well worth it in the long run

probably ok i would imagine, although maplins don't list inductive loading for any of their relays, whazzup actually phoned and the guy said they didn't have an inductive rating, but whether the guy actually knew what he was on about or not...... i'd like to see the proper data sheets for maplins relays but they're unavailable (unavailable as in i'm not putting any more effort than googling it to find them )

Silver Cadmium Oxide: Silver cadmium oxide (AgCdO) has become very popular as a general-purpose contact material in medium to high current switching applications because of its excellent resistance to erosion and welding and its very high electrical and thermal conductivity. AgCdO is produced by mixing silver and cadmium oxide using powder metallurgy techniques. The result is a material with a conductivity and contact resistance (using somewhat higher contact pressures) that is close to that of silver but with superior erosion and welding resistance due to the inherent welding resistance and arc-quenching characteristics of cadmium oxide. Usual AgCdO contact materials contain 10-15% cadmium oxide. Resistance to sticking or welding improves as the cadmium oxide content increases; however, electrical conductivity decreases and cold working characteristics degrade due to decreases ductility.

Silver Cadmium oxide contacts are available either post-oxidized or pre-oxidized. Pre-oxidized material has been internally oxidized prior to forming into contacts and contains more uniformly distributed cadmium oxide than does post-oxidizing which tends to bring the cadmium oxide closer to the contact surface. Post-oxidized contacts may pose problems with surface cracking if the contact shape must be changed appreciably subsequent to oxidization as is the case with double-headed, moving-blade, form-C contact rivets.


i'd say go for it, i would be extremely suprised if it did weld on with just a single 600 on it.

e2a: although as tremont says, you can get a better one for the same price, i'll do a quick google and pm ya a good'un

Nice one ill be building it 2mo afternoon hopefully I will be getting a proper one eventually just struggling with funds as christmas is coming! Ill see if I can find any data sheets as well and post them on here!

Found some more info on the relay if this is any good?

http://www.beta.com.tw/product_detail.php?serial=12

hmmm.... the ac3 rating (good old maplins, no inductive loads, pah) is about 750watts @ 120v (one horsepower - about 6A) this is basically the amount of current in the arc that the contacts can withstand without failing, so might be cutting it a bit fine actually, as the welding on is caused by the capacitor as well as the inductor, when the relay closes the contacts 'bounce' i.e. don't settle closed straight away, they bounce off each other for a split second, opening the contact, now a capacitor when first switched on acts like a short circuit, so pulls a very high current for just a split second, unfortunately this happens at the same time the contact is closing. those contacts are rated to withstand a 750w arc (spark) but during closing of the contacts (and the bounce) the inrush current of the capacitor is way above 6A (worked it out to be roughly 30A peak current for the average capacitor in a 600w lamp). it's all very hit and miss though, the contacts wont bounce at exactly the right time as the capacitors peak current, the contacts may only bounce for a micro second, etc etc which is why often timers will work for ages (sometimes years) before failing totally randomly because it just happened to all happen at the same (wrong) time. i'll give you the part no. of the relay i mentioned in the pm earlier, so i take back what i said earlier, and this relay is best avoided

Very gratefull scraglor!!

Blimey Scraglor, I had no idea there was so much in it !

Personally I have always had a good instinct for a scrounging opportunity and have managed to get mine for free from friendly electrical contractors - I've had two secondhand 40 amp industrial contactors happily starting my 250s for over 12 years off and on.

Didn't I read that you can wire relay contacts in series to improve their inductive load rating ?

Got so much to learn! And what a great place and great people to learn from!

extends the arc. don't ever connect terminals in parrallel to split a single load though (seperate loads can of course have seperate contacts though), as the contacts will never open perfectly at the same time, so the entire load ends up going through a single contact each time anyway.

good bit of info on capacitor switching

http://library.abb.com/global/scot/scot209...101140C0202.pdf

So they can run in series but not parrallel?