Low Voltage Lighting

[esp-protocol]

Okay.... possibly silly question but.....

250 watt switch, how many 12 volt 50 watt down lights with their own trannies can be switched ?

thanks

[breff]

If its not a trick question surely 5.

[amateurandy]

Okay.... possibly silly question but.....

250 watt switch, how many 12 volt 50 watt down lights with their own trannies can be switched ?

thanks

Er 5*50watts = 250watts so I guess not more than 5?

Unless you're triggering relays of some sort.....

[Pierre]

I make it 5 maximum.

If I remember correctly; the power(Watts) is the product of the voltage (Volts) and the current (Amps). The power remains the same on both sides of the transformer.The current goes up, as the voltage drops to 12v, to maintain the equilibrium. Therefore No. of fittings = 250 divided by 50.

I think I could have explained that a lot better but it may have taken all night. Hopefully someone else will jump in with a clearer explanation!!

Are you using a dimmer switch?

[luggsey]

Okay.... possibly silly question but.....

250 watt switch, how many 12 volt 50 watt down lights with their own trannies can be switched ?

thanks

Can you confirm what this "250 watt" switch is, sounds a bit strange to me, normal plate switches are at least 5 amps?

What is this switch exactly?

Also are the transformers new electronic ones or old wound transformer type?

[esp-protocol]

I make it 5 maximum.

If I remember correctly; the power(Watts) is the product of the voltage (Volts) and the current (Amps). The power remains the same on both sides of the transformer.The current goes up, as the voltage drops to 12v, to maintain the equilibrium. Therefore No. of fittings = 250 divided by 50.

I think I could have explained that a lot better but it may have taken all night. Hopefully someone else will jump in with a clearer explanation!!

Are you using a dimmer switch?

Yep..... dimmer switch, 250watt rated for use with electronic transformers....

Ok so if the power is to remain balanced..... we have 250 watts at 12 volts....(roughly speaking 4 amps per fitting)

If the power remains constant then surely on the mains side the equivalent of 250 watts will be 250w / 230 volts = 1 amp

Otherwise a "normal" lighting circuit would have to be fused at 20 amp + for 5 down lighters????

God where's my college books !?

[luggsey]

Yep..... dimmer switch, 250watt rated for use with electronic transformers....

Ok so if the power is to remain balanced..... we have 250 watts at 12 volts....(roughly speaking 4 amps per fitting)

If the power remains constant then surely on the mains side the equivalent of 250 watts will be 250w / 230 volts = 1 amp

Otherwise a "normal" lighting circuit would have to be fused at 20 amp + for 5 down lighters????

God where's my college books !?

If you load the dimmer with 250 watt of halogen lamps the load will be more then 250 watts at the dimmer as you have the losses in the transformers and the wiring.

Try 200 watts of halogen to be the side of caution IMO.

I take it you are using dimmable transformers as well?

[esp-protocol]

If you load the dimmer with 250 watt of halogen lamps the load will be more then 250 watts at the dimmer as you have the losses in the transformers and the wiring.

Try 200 watts of halogen to be the side of caution IMO.

I take it you are using dimmable transformers as well?

Even if you use 4 lamps totalling 200w and account for some losses, you are still talking around 16 amps being pulled through the switch which I can't believe !!

Where's Lurch when you need him ?????!!!!!!!

[Service Engineer]

Okay.... possibly silly question but.....

250 watt switch, how many 12 volt 50 watt down lights with their own trannies can be switched ?

thanks

Surely as you double voltage you half the current.?

So if 12v=50w

then 24v=25w etc, etc,

and 240v = 2.5w

At 240V each unit draws 2.5W but i'll say 2.4 to make it easier to calculate

So if 240w AT 240V = 1 AMP

Then 2.4W AT 240V = 0.1A

So each 50W at 12V unit will require approx 0.1A of current from 240V

So that means you can fit upto 10 units, cus if each unit draws 0.1A of 240V, then 10 units would draw 1A.

Obviously the above is only approximate, so's to be safe i'd say no more than 9 units.

[luggsey]

Even if you use 4 lamps totalling 200w and account for some losses, you are still talking around 16 amps being pulled through the switch which I can't believe !!

Where's Lurch when you need him ?????!!!!!!!

Ok, look at your transformers closely for detail of the current they pull at full load, it's always printed on them. Go from there and it should be understandable.

Or use this.

Calculator