[fantasy-experimental]

i dont really know what a relay is ...
i used mechanical timer to support 2fluoro+2tube lamps
now im wiring up a led-lamp myself with 12v input
would that need a relay too or can i stick to my classic mechanical timer ? (i think though its not working properly 100% it stays 1hour behind chedule per 1/2weeks)

[Muppet]

fantasy-experimental, on Jun 3 2006, 03:49 PM, said:

i dont really know what a relay is ...
i used mechanical timer to support 2fluoro+2tube lamps
now im wiring up a led-lamp myself with 12v input
would that need a relay too or can i stick to my classic mechanical timer ? (i think though its not working properly 100% it stays 1hour behind chedule per 1/2weeks)

LED's wouldn't need a contactor, at least i imagine they wouldn't! After all they're just diodes which don't need a big 'kick' to get 'em started.

[aventinusdampf]

here a relay wired in a junction box, dunno if it was necessary, but did it anyway.

[aventinusdampf]

Rex Mundi, on Mar 25 2006, 04:27 AM, said:

But, what about my 200W enviro?
I imagine it also has a start-up surge, and I'm sure there is an inductor in the built-in ballast part of it, so perhaps it might be prudent to use a relay here too?

That was exactly my thought about it. With a little experience it's easy to wire a relay. They're quite expensive for the materials used, but fairly cheap considered the money ~ 8 - 9,- €.

[Dalbeag]

Parfait, on Aug 10 2006, 01:02 PM, said:

I run a 250w with a contactor.

Even if you use a digital timer - it still has a mechanical device that will swith. If it's an digital switch (i doubt) device, then i guess i'm talking atomic level. But most digital timers have a mechanical switch, when it comes to it.

£35.

And a fire and smoke alarm

£20

Best £55 i EVER spent on my grow.

Spend another £20 or so on a decent powder fire extinguisher

[aventinusdampf]

^^^same here. Smoke alarms everywhere and fire extinguisher. Every house hold should have them. I mean, I prefer at least to be able to extinguish a burning pan in the kitchen by myself.

[PUREWEED]

H.I.D. lights create a large surge of electricity when they are turned on (esp 400w plus), up to twice the normal running power and this will increase as the lamps get older. Household timers are not designed to take this load and the contacts in the timer weld together. The initial large inrush of power is caused by the large power factor correction capacitor in the ballast unit, and happens for just a fraction of a second. Here's some average figures:

250w start up amps = 2.3 / running amps = 1.5
400w start up amps = 3.6 / running amps = 2.3
6000w start up amps = 4.5 / running amps = 3.2
1,000w start up amps = 7.0 / running amps = 5.0

So, to avoid your timers blowing you need to get a horticultural lighting contactor (heavy duty relay unit). The smallest one (2 way) is suitable for up to 2K of lighting and is around £35. This will deal with the load, any segmental timer will do as only the dial is functioning. Note: contactors require two plug sockets.

Micky Mouse methods are of course Argos timers, and some computer extension leads which have surge protection up to 400w. But for the extra £20 a proper contactor is definately the way to go.

[ryanbad]

Hi

Would I need a contactor/relay for my growroom? I'm planning on using 2 x 200W enviros? Sorry if it's a stupid question but I have no idea when it comes to electrics.

Also, could someone explain to me what an RCD is and if I need one.

Cheers

[zym zym]

you say you need 2 sockets for the ralay ??? im only gonna run a 250w so would i need 2 wall sockets ??

[mjc]

If you've read this far, and have a problem like this, you've gotta check your rig. A 200 watter shouldn't be blowing timers. You don't hear of microwave ovens doing this.

You should check to see if you have a short, or some other electrical problem. Of couse they do have timers rated for amperage, get one to match your breaker or fuse

Also, something else might be on the same circuit that you could plug in elsewhere.

Anyways, all the previous safety features, like extinguisher, etc are definitely needed.

And check out a GFCI - ground fault circuit interruptor. If you do have a short, and you never know, it could save your life - any time near water.

[Scribb|e]

Do you have your microwave oven on a timer? Why?!

Also, do microwave ovens create a surge of inrush current like light ballasts and other high-current inductive decices do? I don't believe they do, which renders your argument a little weak, in relation to the presumed nature of the current load.

[Budsucker]

Scribb|e, on Nov 13 2006, 09:42 PM, said:

Do you have your microwave oven on a timer? Why?!

Also, do microwave ovens create a surge of inrush current like light ballasts and other high-current inductive decices do? I don't believe they do, which renders your argument a little weak, in relation to the presumed nature of the current load.

and more importantly the power used by a microwage is resistive, a ballast is inductive which basically means that the the AC sine wave for the voltage and the current is out of phase, meaning they can use a lot more power than the rated wattage of the bulb and even though this can be said said to use upto 1.8 times more power than the just the bulb the nature of this type of supply can still melt timers. If you check the timer box you will find a warning stating it is not suitable for inductive loads or a figure in brackets which will be its inductive tolerance greatly reduced from the rated 13Amps of the timer.

An old traditional style ballast especially the cheap ones can easily use upto twice the amount of power that most people think. If you want more info try googling/wikidpedia 'apparent power'.


....Anyways if your using hids or fluorescents use a contactor it is not worth taking the risk

[steevo]

DISCLAIMER** I or uk420 or any affiliates take no responsibility for any electrical work carried out whatsoever!

PUREWEED, on Aug 25 2006, 02:10 PM, said:

H.I.D. lights create a large surge of electricity when they are turned on (esp 400w plus), up to twice the normal running power and this will increase as the lamps get older. Household timers are not designed to take this load and the contacts in the timer weld together. The initial large inrush of power is caused by the large power factor correction capacitor in the ballast unit, and happens for just a fraction of a second. Here's some average figures:

250w start up amps = 2.3 / running amps = 1.5
400w start up amps = 3.6 / running amps = 2.3
6000w start up amps = 4.5 / running amps = 3.2
1,000w start up amps = 7.0 / running amps = 5.0

So, to avoid your timers blowing you need to get a horticultural lighting contactor (heavy duty relay unit). The smallest one (2 way) is suitable for up to 2K of lighting and is around £35. This will deal with the load, any segmental timer will do as only the dial is functioning. Note: contactors require two plug sockets.

Micky Mouse methods are of course Argos timers, and some computer extension leads which have surge protection up to 400w. But for the extra £20 a proper contactor is definately the way to go.

Where did these measurements come from

Wattage divided by Voltage will give you Amperage, so in the case of a 250 it's..
250(watts) divided by 240(volts) = 1.042(Amps) 'normal running' so, if those start up amps are correct then this £5 timer from maplin will be perfect and no relay is needed..
http://www.maplin.co.uk/Module.aspx?Module...r&doy=14m11

Quote

Maplin:
Maximum load this timer can take is 3kW

ok boss..
Volts x Amps = Watts
sticking to the 250, if you have higher you can do the math yourself it's all there
240(volts) x 2.3amps(initial load) = 552(Watts)

Now my point is, the timers are no doubt up to uk electrical standards (they wouldn't sell them otherwise) and can merrily handle the inductive loads of the lights going on.

Don't get me wrong, i'll be investing in a contactor/relay but we'll get away with atleast 1 grow first, anyhoo we are always here for lights on and off

This post has been edited by steevo: 14 November 2006 - 09:40 AM

[Scribb|e]

I'm afraid that this advice is incorrect - you're not taking into account the fact that light ballasts are an *inductive* load, where the specs quoted on the timers is for a *resistive* load. (Sometimes they give the inductive load max value in brackets after the resistive value)

From Maplin's '7-day Timer' description Q&A:

Quote

7 Day Digital Timer FAQ's:
Q) What is the max inductive load for this switch. - paul morley
A) 3 Amps