why is this light switch not suitable for flourecent lights

Louisc

http://cgi.ebay.co.uk/Movement-Activated-Smart-Light-Switch_W0QQitemZ200385775112QQcmdZViewItemQQptZUK_CCTV?hash=item2ea7ec4608&_trksid=p3286.c0.m14


Just looking at this switch on ebay, it says that "Please note this product is not for use with fluorescent tubes or light fittings which use low voltage transformers."

I wonder why

Surely a switch is a switch regardless of whether its kicked on by a button or some a light sensor.
When on, Im thinking it completes a 220V circuit, and the circuit doesnt care if the light is flourescent or not, or if there is a transformer or not.

Why does it say that its not suitable for flourecent, what possible reason could there be ?

Ive got one switch for 6 * 6watt flourecent tubes in my kitchen that I want to turn on automatically

Could have something got to do with capacitance and all that technical sh1te.

Gurgle

Louisc wrote: »

Just looking at this switch on ebay, it says that "Please note this product is not for use with fluorescent tubes or light fittings which use low voltage transformers."

I wonder why

Surely a switch is a switch regardless of whether its kicked on by a button or some a light sensor.
When on, Im thinking it completes a 220V circuit, and the circuit doesnt care if the light is flourescent or not, or if there is a transformer or not.

Why does it say that its not suitable for flourecent, what possible reason could there be ?

When the motion sensor is activated, a relay is closed by the controller.

Transformers and florescent bulbs' starters throw a high voltage spike (Back EMF) when they're first powered on which could toast the relay or even the control circuit.

Louisc

Gurgle wrote: »

When the motion sensor is activated, a relay is closed by the controller.

Transformers and florescent bulbs' starters throw a high voltage spike (Back EMF) when they're first powered on which could toast the relay or even the control circuit.

Thanks Gurgle

My little flourecent lights, I have 5 of them connected together

they are just 6watts each, for undercounter lighting

I dont think they have a starter. ......... I certainly don't see a starter, unless there is one internally.
When turned on, they come on instantly, in the same manner as a CFL bulb, there is no labouring and flickering before it turns on.

Does this mean I can use the sensor ? Will my low powered flourecent bulbs give rise to high voltage spike ?

Gurgle

Louisc wrote: »

Thanks Gurgle

My little flourecent lights, I have 5 of them connected together

they are just 6watts each, for undercounter lighting

I dont think they have a starter. ......... I certainly don't see a starter, unless there is one internally.
When turned on, they come on instantly, in the same manner as a CFL bulb, there is no labouring and flickering before it turns on.

Does this mean I can use the sensor ? Will my low powered flourecent bulbs give rise to high voltage spike ?

It sounds like they're actually CFL rather than old-style florescents. Do you have a make/model for the lights ?
Might be able to find the specs.

Louisc

Gurgle wrote: »

It sounds like they're actually CFL rather than old-style florescents. Do you have a make/model for the lights ?
Might be able to find the specs.

It's just some cheap lights i picked up on ebay, very cheap, but good quality.
I think i will probably get the sensor, if it causes the sensor to stop working I shall replace it with a manual switch.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120450517698

Azelfafage

Louisc wrote: »

Just looking at this switch on ebay, it says that "Please note this product is not for use with fluorescent tubes or light fittings which use low voltage transformers."

I wonder why?

In the initial second of turning on any flourescent tube an amazingly large surge current is generated.

Energy saving bulbs are the same...they are folded up flourescent bulbs.

This is ok because the ionising current dies down in a second or two and the bulb becomes truly energy saving.

(Hint: If you see a flourescent tube flickering and failing to turn on.... your electricity meter will be spinning and wasting money.Fix it! Buy a new "ballast capacitor".)

The INITIAL current for flourescents can burn out low cost switching devices..and dimmer switches.

.

.

Azelfafage

Gurgle wrote: »

It sounds like they're actually CFL rather than old-style florescents.

Forgot to mention.

CFL = Compact Fluorescent Lamps.

CFLs are the exact same think as old fashioned fluorescents.

Just,as the label says,more compact.
.

Louisc

Azelfafage wrote: »

Forgot to mention.

CFL = Compact Fluorescent Lamps.

CFLs are the exact same think as old fashioned fluorescents.

Just,as the label says,more compact.
.

But CFLs don't have a starter do they ? At least not a replaceable one.
The flourecent tubes in our kitchen in the 1980s had a starter ---- it needed changing periodically.

Azelfafage

Louisc wrote: »

But CFLs don't have a starter do they ? At least not a replaceable one.
The flourecent tubes in our kitchen in the 1980s had a starter ---- it needed changing periodically.

They still do.

When it the bulb does fail it willl almost certainly be because of the the embedded starter.

If the starter in a CFL were replaceable then the bulb would last for a thousand years.

The manufacturers cannot wait that long as they pollute the skies.

I like to see the stars.
.

Mellor

Louisc wrote: »

But CFLs don't have a starter do they ? At least not a replaceable one.
The flourecent tubes in our kitchen in the 1980s had a starter ---- it needed changing periodically.

The starter, or ballast, is internal.
This is to make them more commercial and suitable for bayonette and edisonson (ie standard) fittings