Low Voltage Light Question

[down2earth]

Hi all,

Chum at work has 18 LV lights in the kitchen using the G4 5W halogen bulbs. Two bulbs failed but he could only get 10W replacements. Two questions

1. Will there be any detrimental affect having 2 of the 18 bulbs being 10W

2. If he replace all 18 bulbs with 10W, would this provide more light or would they all be a bit dimmer because the transformer is still pushing out the same power.

All replies gratefully recieved

Down2earth

 

[boatnik1]

It's all totally dependant on the wattage output of the transformer. If it's only 90w then it's working at its limit with 18 5w bulbs and to increase the load by introducing higher wattage bulbs will overheat and eventually kill the transformer. Changeing all the lamps to 10w will require a transformer output of a minimum of 180w. You could also split the lights into two lots of nine and use a second transformer at 90w to drive the second string of nine.

 

[pushrod]

It's all totally dependant on the wattage output of the transformer. If it's only 90w then it's working at its limit with 18 5w bulbs and to increase the load by introducing higher wattage bulbs will overheat and eventually kill the transformer. Changeing all the lamps to 10w will require a transformer output of a minimum of 180w. You could also split the lights into two lots of nine and use a second transformer at 90w to drive the second string of nine.

Hi boatnik don't think its quite as straight forward as that - the transformer will have an output in VA not watts and the wattage of the bulbs will be subject to a loading factor of 1.8 (unless otherwise specified).

 

[Phil Mumford]

The transformer will likely be 150 VA if one transformer is being used - could be a 250VA unit. Could be several transformers of 50/60VA each. Just do the sums and ensure you do not exceed the rating of the transformer(s). For this application W = VA as this is a resistive load.

Using different output lamps should not be a problem - mix and match as you wish.

 

[electricAl]

Hi boatnik don't think its quite as straight forward as that - the transformer will have an output in VA not watts and the wattage of the bulbs will be subject to a loading factor of 1.8 (unless otherwise specified).

Think you`ll find the 1.8 factor (inverse of a conservative 0.55 pf) is applicable for inductive discharge lighting & not halogens

As Phil stated, halogens are purely resistive loads.

 

[pushrod]

Think you`ll find the 1.8 factor (inverse of a conservative 0.55 pf) is applicable for inductive discharge lighting & not halogens

As Phil stated, halogens are purely resistive loads.

Yes realised after i posted that i had not payed enough attention to the type of lighting, but had passed the edit period before the penny dropped