Illuminated Mirror in Bathroom

[sparkyjohn1]

Hi,
I've been asked to Install a Illuminated Mirror in a bathroom, ( inc. shaver socket, digital clock ect. ) Quite standard, as I've Installed them before.. The L.E.D 's come on via a pull cord at the bottom of the Mirror. The customer wants more L.E.D's in the bath panel, to be operated from the same pull cord on the mirror.
After looking at the Wattage that the transformer in the mirror is rated, I don't think this can be achieved, due to overloading. Is it possible to add another tranny in the mirror to supply to bath lights from the same switch.? Only other option is to increase the tranny in the mirror so it can cope with the extra load, ( this would void warranty tho,,) Any help would be grateful.. See pictures..

 

[R G]

The diagrams are showing the outgoing side of the transformers are switched , are you sure , because its normally the supply thats switched , if so it would be possible to achieve what you want , another driver could be fitted else where ,,

Another thought ,, if the load side is switched then a contactor may be available with a coil voltage to match the output of the driver , that could be used to control another circuit if required,,

 

[sparkyjohn1]

The diagrams are showing the outgoing side of the transformers are switched , are you sure , because its normally the supply thats switched , if so it would be possible to achieve what you want , another driver could be fitted else where ,,



Here is the diagram--- if another transformer is used...
Basically using the switch in parallel to switch on 2 circuits from 2 different supplies.. I don't really want to commit to doing it , to be honest, as don't know if the current drawn will be adequately split between the two supplies, Please let me know your opinion,, thanks..

 

[davesparks]

LED driver outputs would not normally be suitable to operate a relay or contactor, they are normally constant current supplies which vary the voltage to maintain current.

Your first port of call with this would be to contact the manufacturers for their advice.

 

[davesparks]

The diagrams are showing the outgoing side of the transformers are switched , are you sure , because its normally the supply thats switched , if so it would be possible to achieve what you want , another driver could be fitted else where ,,View attachment 24436



Here is the diagram--- if another transformer is used...
Basically using the switch in parallel to switch on 2 circuits from 2 different supplies.. I don't really want to commit to doing it , to be honest, as don't know if the current drawn will be adequately split between the two supplies, Please let me know your opinion,, thanks..

Go on, connect it up like that, but be sure to have the video camera running when you switch it on!

A fire extinguisher would probably be useful too

 

[sparkyjohn1]

Mate,, I asked for honest , decent advice and opinion,, not a sarcastic remark... sure you have come across problems in the past when you needed a bit of guidance,, or another opinion,,, I've given you all the details (and taken time to do basic drawings ). Was only asking for a solution bud,,..

 

[davesparks]

1 I'm not your mate, I've never even met you
2 i gave my best advice in the post above
3 yes I've come across problems where I've needed advice before, and if I've gone on to ask a blatantly obvious question have been met with laughter and ridicule. How do I react? I laugh along with them.

When I ask a question to which the answer should be obvious to a time served electrician then you may take the **** as much as you like, I'll more than likely join in with you when I realise my mistake!

 

[sparkyjohn1]

Dave,Y
This isn't a straight- forward D.I.Y question.. hope you can appreciate that.. I am time served ( 5 years at college). and been doing Domestic / small commercial works for the past 5 years.. I jus wanted a decent reply, that's all........ no need to be ****** about it.. I don't claim to know everything, nor do I parade round claiming I'm the best spark... QUOTE:: '''There's always someone with a bigger car,, There's always someone with a bigger Cigar''''... Easops Fable== roughly translates into, no matter how much you know, or own,,, or how much knowledge you have,, there is always someone who has more..///////////////// The sparks union are always learning with the new technology that is being invented... we need to keep up, bud..
It was an honest question, and I'd appreciate an honest reply,, thanks..
J.d

 

[davesparks]

I have given an honest reply, ask the manufacturer if the equipment you are wishing to alter.

I also gave an honest answer to your suggestion of joining the output of an led driver to the out put of a transformer, keep a fire extinguisher handy when you turn it on!

 

[sparkyjohn1]

That wasn't he question tho,,,, . I wanted to know if you could use, the same switch to turn on 2 separate circuits, from 2 different power supplies..... I know this would mean it would be parallel in and out of the switch,,, just wondering if it would induce problems regarding flow of current,,,. as current tends to split, if circuit is parallel //,, ?

 

[R G]

There are dc coil contators available ,I did look them up , what you could do is measure the outgoing voltage of the driver and match it up , I did find some available on line , with fairly low voltages ,,,,

 

[sparkyjohn1]

thanks Ray, Finally, a decent answer... the L.E.D's are quite standard 12 volt. about 2.5 Watts( a bank of them)... x 3.. overall about 7.5 / 8 Watts in total.. After the ****** comments previously, decided to switch it separate- *removed*

 

[davesparks]

There are dc coil contators available ,I did look them up , what you could do is measure the outgoing voltage of the driver and match it up , I did find some available on line , with fairly low voltages ,,,,

I'll say it again, led drivers are constant current supplies. They vary the voltage to keep current constant.
A contactor coil requires a constant voltage supply, the two are not compatible.
For example if the contactor coil is 12V and normally draws 50mA when energised but you connect it to a 100mA led driver the driver will increase the output voltage until it achieves an output of 100mA, at this point the coil will melt.

 

[davesparks]

That wasn't he question tho,,,, . I wanted to know if you could use, the same switch to turn on 2 separate circuits, from 2 different power supplies..... I know this would mean it would be parallel in and out of the switch,,, just wondering if it would induce problems regarding flow of current,,,. as current tends to split, if circuit is parallel //,, ?

Yes you will inevitably get a flow of current from the out put of one supply into the output of the other.
The ultimate result if this will be a fire.

If you can swap the switch for a double pole switch it will be able to switch each supply independently.
When ordering a low voltage switch you would expect the switch to be identified as DPST although a DPDT would be more common and also work.

 

[Simlec]

I'll say it again, led drivers are constant current supplies. They vary the voltage to keep current constant.
A contactor coil requires a constant voltage supply, the two are not compatible.
For example if the contactor coil is 12V and normally draws 50mA when energised but you connect it to a 100mA led driver the driver will increase the output voltage until it achieves an output of 100mA, at this point the coil will melt.

Depends on how the LEDs are connected! Not all are constant current !

 

[davesparks]

If if isn't constant current then it's not a driver, it's a regulated DC power supply.

 

[R G]

I would check the driver output , there are 2 types a CC and CV , (constant current and constant voltage) just looked them up , If its CV I would measure the output with lamps on even though it may say 12V on the driver or whatever and then you can decide ,

 

[Simlec]

Constant voltage driver for LEDs
In a parallel circuit, the voltage is the same through all components (LEDs), but the current is divided through each.

Constant current driver for LEDs
In a series circuit, the current is the same, but the voltage is divided.

They are both regulated power supply's but different types to suit the correct load.

 

[R G]

Constant voltage driver for LEDs
In a parallel circuit, the voltage is the same through all components (LEDs), but the current is divided through each.

Constant current driver for LEDs
In a series circuit, the current is the same, but the voltage is divided.

They are both regulated power supply's but different types to suit the correct load.

Thats exactly what I had just read ,,,

 

[sparkyjohn1]

Simlec, I thought this might be the case,,- as per the electrical theory i did at college... Was thinking about current splitting,, ( if voltage stays the same )// which is the case , as it's after the 12 volt D.C output.///
One switch to bring on 2 circuits, would be pushing boundaries I will liaise with customer to include a separate switch into the circuit.. Thinking about it,,, One switch to switch on 2 separate loads, could instigate problems,, as load would be divided,, not load to each tranny.. Good feedback, bud,, Thank you