Controlling Lights with Step-Down Transformer

[Guest guest]

Action Lighting has a variety of 24 volt, clip lighting strings on sale. (for example, 100 ft with 10 inch spacing for $25) http://www.actionlighting.com/items.asp?MainCategory=Specials&Sub=OnSpecial

Can LOR be used to control anything that requires this 24 volt step-down transformer?

Denny

[Guest guest]

Denny transformers can be switch on and off with LOR channels but you will not be able to use fade or shimmer effects.

[Guest guest]

Be careful using inductive loads with a triac output like on the LOR boards. The difference between the current and voltage in an inductive circuit causes triacs to fail. No dimming functions absolutely.

[Guest guest]

radioguy1007 wrote:

Be careful using inductive loads with a triac output like on the LOR boards. The difference between the current and voltage in an inductive circuit causes triacs to fail. No dimming functions absolutely.

We do use snubberless triacs that help with the control of inductive loads. We have had people dim transformers with some success but it is not recommended. If you want to test dimming be prepared to smoke the transformer.

There was a person in the UK (I think) that did testing on transformers... He had pretty good success.

[Guest guest]

LightORama wrote:

radioguy1007 wrote:

Be careful using inductive loads with a triac output like on the LOR boards. The difference between the current and voltage in an inductive circuit causes triacs to fail. No dimming functions absolutely.

Good advise. We do not use standard traics, we use snubberless triacs that help with the control of inductive loads. We have had people dim transformers with some success but it is not recommended. If you want to test dimming be prepared to smoke the transformer.

There was a person in the UK (I think) that did testing on transformers... He had pretty good success.

[Guest guest]

LightORama wrote:

radioguy1007 wrote:

Be careful using inductive loads with a triac output like on the LOR boards. The difference between the current and voltage in an inductive circuit causes triacs to fail. No dimming functions absolutely.

We do use snubberless triacs that help with the control of inductive loads. We have had people dim transformers with some success but it is not recommended. If you want to test dimming be prepared to smoke the transformer.

There was a person in the UK (I think) that did testing on transformers... He had pretty good success.

In Oz most of the light strings are run with 240V stepdown transformers (to 12, 18, 24, 35V). Last year I tested several arrangements before trying them in an animation display. I ran tests with various switch rates and with dimming on both mini lights and LEDs.

Had no problems with triac failure on my 2 boards. Dimming was no problem - no noticeable heating of the transformers. Dimming LEDs was not as predictable as minis, but still provided a dimming effect.

Continuous rapid switching can result in additional transformer heat generation and could thus lead to failures, however, I never had one fail. It takes considerable time for the transformer temperatures to stabilise in operation (>1hr), so provided rapid switching (0.1 s) is not continuous, short bursts at a high rate seem OK. Note, that the heat build up is also dependent on the actual load on the transformer.

I am planning a synched show this year and now have 80 channels most of which will be switching transformer coupled lights.

Regards - Geoff

[Guest guest]

Bill Foley wrote:

Denny transformers can be switch on and off with LOR channels but you will not be able to use fade or shimmer effects.

I've always heard that if you switch transformers on and off a lot they will burn out.

TED