Dimmer Problem

[johnpt]

Hi I have got a problem with dimmer switches. I was installing two in an apt in the bathroom. The lights were low voltage halogen i think. When i changed switch to the dimmers and tryed to dim them they dimmed alright but they was a very loud humming from the fuseboard. I looked at fuse board and there appeared to be what looked like a contactor or MCB with a light on it. I have never seen anything like this before. What could this be. It wasnt a normal MCB buy was about same size. It definetly controlled the bathroom lights as when i tripped the switch it turned off the lights.

Thanks in advance for advice

 

[green-hornet]

sounds like a din mounted transformer to me.

In which case the lighting would not be compatable with a dimmer switch.

 

[johnpt]

Thanks for reply.

Is there anyway around this? Have I any options.

Thanks in advance

 

[johnpt]

The lights do dim but just a loud humming from fuseboard. Thanks

 

[green-hornet]

They are not meant to be dimmed, thats why you hear the loud noise its trying to shout "Dont dim me please" in agony.

The lights you have will be 12v halogen, you would need to replace the transformer with one that would dim the effective loading.

All dimmers have different ratings, the one fitted would be older than the newer models available.

If its din mounted it could be costly as well.

 

[johnpt]

Thanks for reply very helpful.

There is just 4 lights in bathroom.

So u can get a dim mounted transformer that dims? How much roughly would this cost.

The other lights in house are also on a contactor but it seems alot bigger than the one for bathroom (Like size of an RCD) and they dim ok. Is it something like this I need.

Thanks really appreciate advice

 

[green-hornet]

A contactor is very different from a transformer.

A contactor is used when switching larger loads, if it is a contactor then the main lights may be mains voltage and would normally dim ok.

If it is a transformer it would be compatable with the lighting.

Really we need to see some photo's of the mounted contactor/transformer, that way we can see what you have and give more detailed advise.

 

[green-hornet]

see here

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=compareProducts&originalProduct=4229637&alternativeProduct=2889347

 

[johnpt]

thanks a million for all help will try get picture

 

[sparkyrj]

maybee you could replace the transformer with an mcb/rcbo, and fit individual dimmable transformers to the 4 lights.

 

[Badger]

maybee you could replace the transformer with an mcb/rcbo, and fit individual dimmable transformers to the 4 lights.

this sounds the better option in my opinion.

 

[green-hornet]

maybee you could replace the transformer with an mcb/rcbo, and fit individual dimmable transformers to the 4 lights.

Would appear to be the best way forward, I never thought of that to be honest.

 

[johnpt]

Thanks for reply.

Just few questions why would somebody use din rail transformer instead of individual transformers?

2 Are they expensive din rail transformers?

3 Is it possible to get a dimmable din rail transformer and are these expensive?

Thanks a million for all the advice in advance

 

[green-hornet]

Most din rail applications are used for commercial and industrial, the electrician who installed it may have worked in the industry and used parts obtained from his works to do the house.

They are more expensive but are easily monitered and exchanged etc.

You can almost get any electrical devise din rail mountable but as I have said they do work out more expensive than individual componants.

 

[Mark2spark]

I'll agree with the others, you appear to be trying to dim the downlights AFTER the voltage has been stepped down to 12V, which is a no no :_|

How about changing the lamps to 35W or even 20W to get that 'already dimmed' looked

 

[johnpt]

Thanks. I would change bulbs but the lady wants to dim them as all other lights in apt have dimmers

Just one more query on it. What way are these wired? At the switch there appears to be two switch wires. Why would that be?

Thanks

 

[green-hornet]

without seeing or testing we could not answer that definitavely.

Do you mean two pairs of switch wires? If yes them it could mean two seperate banks are switched from the same switch.

If not two pairs could be two way switching or power taken first to switch and then to the lights. Like I said you need to test each cable and see where it goes.

 

[johnpt]

Hi

Sorry for late reply. I checked lights and there Gu10 bulbs. It appears that they is a contactor on fuse board for each bathroom. When i turn on switch the contactor light comes on. Is it possible that these contactors cannot be used when i put the dimmer switch on. The lights will dim but a loud humming from fuse board. I have enclosed pictures.

Thanks in advance for advice

 

[johnpt]

Hi i posted before but have little more info now. I have bathroom spotlights GU10 bulbs which when i put dimmer on instead of switch there was loud humming from fuseboard. I checked fuseboard and lights for each bathroom seem to be powered by a relay. A fan also turns on when lights switched on.

Looking at the switch there is 2 switch wires.

What would reason for using relay?

Is it possible to change this so i can dim lights?

Thanks in advance for any replies