Dusk to dawn sensor problem

[Alanm3]

Hello all, First posting on here, so be gentle please! ;>)

I have a row of halogen lights under my garage soffit which are fed via a dusk to dawn sensor, which in turn is fed from a dimmer inside the house.

Everything has been working fine for around a couple of weeks until the other night, they didn't come on as expected.

I measured the input voltage on the sensor at 28V A/C, but no amount of covering the sensor, or putting the 2 rotary dials fully anti-clockwise (which, according to the instructions should bring the feed on), will give me any output. Based on this I bought another sensor, exact make and type and this has exactly the same issue.
I should add that at this voltage the lights are at the level I wish them to be at.
Now I can take the live output and pair it up with the live input and the lights come on fine, but nothing seems to make the sensor operate. I did read that the input voltage is normal mains 220-240V, but if that's the case, why did it work and suddenly stop?

Any theories will be welcome!

Cheers

Alan

 

[ColJack]

so it goes

mains - dimmer - sensor - lights?

sensors don't like being dimmed, dimmers don't like feeding sensors..

either you nerfed the sensor with the dimmer or the dimmer with the sensor.

 

[Alanm3]

so it goes

mains - dimmer - sensor - lights?

sensors don't like being dimmed, dimmers don't like feeding sensors..

either you nerfed the sensor with the dimmer or the dimmer with the sensor.

Yes, that's the path. The thing is, I don't dim as such, the lights are fixed at the level I want them at, so they aren't being continually changed, but I guess the fact they're dimmed at all could cause problems?

Thanks

 

[Alanm3]

Also, would the fact that the lights some on when the sensor it taken out of the circuit not imply the dimmer was OK? I can't imagine the new d-d sensor would burn out immediately?

 

[ColJack]

so you like running the halogens at about 10% brightness? ( 28V as opposed to 230V? )

they actually burn out faster when dimmed.. they don't get hot enough to re-deposit the tungsten back on the filament.. ( google for halogen cycle.. )

the sensor needs 220 - 240 V to function..
why it worked in the first place I have no idea..

 

[Alanm3]

so you like running the halogens at about 10% brightness? ( 28V as opposed to 230V? )

they actually burn out faster when dimmed.. they don't get hot enough to re-deposit the tungsten back on the filament.. ( google for halogen cycle.. )

the sensor needs 220 - 240 V to function..
why it worked in the first place I have no idea..

Yes, it's more for effect that security.

That's the bit that's confusing me - it worked, now it doesn't!

 

[ColJack]

Also, would the fact that the lights some on when the sensor it taken out of the circuit not imply the dimmer was OK? I can't imagine the new d-d sensor would burn out immediately?

could be the dimmer is duff.. doesn't like the sensor anymore, but the lights alone don't cause it a problem..

turn the dimmer back up full and see if that makes the sensor work.. or link out the dimmer entirely..
this rules out the dimmer then..

 

[Alanm3]

Also, would the fact that the lights some on when the sensor it taken out of the circuit not imply the dimmer was OK? I can't imagine the new d-d sensor would burn out immediately?

could be the dimmer is duff.. doesn't like the sensor anymore, but the lights alone don't cause it a problem..

turn the dimmer back up full and see if that makes the sensor work.. or link out the dimmer entirely..
this rules out the dimmer then..

I did turn it up full and that made no difference. I'll take it out the circuit completely tomorrow and try that,

Thanks

 

[ColJack]

Yes, it's more for effect that security.

That's the bit that's confusing me - it worked, now it doesn't!

28V sounds seriously low for a dimmer though.. is that what you measured it as before when it was working?
maybe someone turned the dimmer down from maybe 130V or something?

if you want dimmer lights,. then fit lower wattage lamps.. you'll save energy too since dimmers don't save you that much.. the dimmer loses a fair bit in heat..

try 10W or 25W if you don't like the 50W ones..

 

[Alanm3]

Yes, it's more for effect that security.

That's the bit that's confusing me - it worked, now it doesn't!

28V sounds seriously low for a dimmer though.. is that what you measured it as before when it was working?
maybe someone turned the dimmer down from maybe 130V or something?

if you want dimmer lights,. then fit lower wattage lamps.. you'll save energy too since dimmers don't save you that much.. the dimmer loses a fair bit in heat..

try 10W or 25W if you don't like the 50W ones..

To be honest, no. I only measured it when it stopped working. The dimmer itself is in a awkward place and has a marking (apencil line drawn by me!) on it to show it's position, which hasn't changed until I turned it up.

 

[ColJack]

link the dimmer out and see if they come on tonight..

 

[Alanm3]

link the dimmer out and see if they come on tonight..

I would but I'm heading out with the wife, so I don't have time tonight.

cheers

 

[Steve]

Stop fannying around with dimmers and transformers. You're wasting energy left right and centre here, for this "effect" on your house, which by your admission serves no useful purpose.

At 10% brightness the halogens will be using 20% energy, and they wont last half as long as halogen lamps run at full brightness.

Fit CFLs or LEDs into mains voltage holders, and you can reduce each lamp's consumption to a couple of watts, genuinely, at full brightness.

Unfortunately, you probably got these fittings from B&Q or even worse, Homebase, where people are actively encouraged to purchase energy-wasting fittings.

 

[ColJack]

who mentions transformers?