Dimmer pull cord problem

[houstonwehaveaproblem]

Fitted a dimmer pull cord from toolstation.

States no neutral required on instructions.

Week later dimmer stops working. (no movement from the actuator when pulling cord)

Replaced with another. Few days later stops working, same as before.

I have 5 x 12v 50w halogen spotlights each has a dimmable transformer fitted

Any ideas what the problem is? Overload? No neutral problem?

Cheers

 

[RF Lighting]

What's the rating of the switch?

 

[houstonwehaveaproblem]

Have just found this info when scouring the net.

Max 250W incandescent load / 175W transformer load

I guess my combined wattage is overloading it?

 

[Taylortwocities]

Do the maths. Is 5x50 = more than 175?

 

[winston1]

You shouldn't dim halogen spotlights anyway, it reduces their life.

 

[securespark]

Do me a favour:

Re-arrange the following letters -

Rabbit use rut push yoke

 

[JohnW2]

You shouldn't dim halogen spotlights anyway, it reduces their life.

I've resisted commenting previously, but am starting to tire of the umpteen times I'm seeing this assertion wheeled out in assorted threads, so ....

As I understand the situation, you and eric (and maybe others) have probably only half-understood what you have read - either that or you haven't read it properly ... dimming a filament lamp is normally expected to result in a considerable increase in the life of the lamp. However, because the lower temperatures of a dimmed halogen lamp interferes with the halogen cycle, the increase in life is usually less (sometimes considerably less) than what would be expected with a standard incandescent filament lamp. However, "not as much increase in life" is obviously very different from "reduction in life".

Kind Regards, John

 

[houstonwehaveaproblem]

Do the maths. Is 5x50 = more than 175?

Im not biting!

 

[Taylortwocities]

Here's a hint

I guess my combined wattage is overloading it?

 

[bernardgreen]

Dimming halogens

My understanding is that the earlier large volume halogen filled lamps did have a shortened life when run below design temperature as the metal vapour could condense on the glass ( quartz ) and thus metal was lost from the filament. The sign of this condensed metal was darkening of the glass.

In modern very low volume lamps, such as capsules, where the glass (quartz ) is perhaps only a milli-metre from the filament the glass itself becomes so hot that the metal vapour cannot condense on it.

 

[houstonwehaveaproblem]

Here's a hint

I guess my combined wattage is overloading it?

Yup

 

[winston1]

... dimming a filament lamp is normally expected to result in a considerable increase in the life of the lamp. However, because the lower temperatures of a dimmed halogen lamp interferes with the halogen cycle, the increase in life is usually less (sometimes considerably less) than what would be expected with a standard incandescent filament lamp. However, "not as much increase in life" is obviously very different from "reduction in life".

Kind Regards, John

Interesting. I've not seen it explained like that before.

Is this actually a proven fact or one of those theories invented to justify doing something you shouldn't?

 

[AndyPRK]

Or you could ask, does anyone dim halogen and experienced short life ?

Even the Gls bulbs have halogen inside these days.

 

[winston1]

Or you could ask, does anyone dim halogen and experienced short life ?

Even the Gls bulbs have halogen inside these days.

Unless you have 2 banks of lights one dimmed and one not all on for the same time it can be difficult to tell.

 

[AndyPRK]

Why ? Because they are so unreliable anyway ?

I would have thought if it was a real & significant problem, you would know about it.