10w globe, 20w transformer on dimmer

Would anyone be able to shed some 'light' on the following....

I have a path light which is only 10w but connected to a 20w ircon core transformer (on a dimmer). I need to run an iron core as the transformer is 10m from the light.

My understanding is that the globe is likely to burn out more quickly as the voltage at the light will be higher than desirable since it is only 10w and the transformer outputs 20w.

If I set the dimmer to max 50% will this solve the problem or should I put in a 20w globe and set to 50% on the dimmer (I don't want more than 10w of output)

Many thanks.

 

Well.. not being an electrickery person.. I stand to be corrected.. but a transformer rated at 20W is CAPABLE of providing 20 watts of power.. its impossible to force 20W into a globe rated at 10W without changing the voltage.

Watts is merely a calculation that involves the current flowing through the globe and the resistance of the globe.. The only way to increase current is to increase the voltage or decrease the resistance..

A 10watt globe on a 20watt transformer will still only draw 10 watts provided the voltage is the same as the original 10 watt transformer.

 

As long as it is the same voltage & you don't go over the maximum wattage it will be fine.
The lamp will only draw what it needs.
If you want you can install two 10 watt lamps but one will be fine.
Changing the dimmer to 50% will do nothing.
You still get the same power out of the transformer.
All the dimmer does is change the wave form.

Rob

 

The difference between a 20 watt globe at 50% and a 10 watt globe at 100% isn't the power consumption. It's the colour temperature.

 

You wont have an issue with this transformer and lamp combination. The rating of the transformer is a maximum, the rating of the lamp is the required. Your under so all good.

What you may have an issue with is minimum loading on a dimmer, this may cause the lamp to pulse, check the minimum load allowed for your dimmer, ensure that you use the lamp rating and not the transformer for this.