Pro Series Dimming

Dear All...

In an installation, in a single lighting circuit we have 12V 35W halogen and 12V 50W Halogen lights. And we are using Electronic transformers which are capable of Trailing edge dimming.

Is it possible to Dim this lighting circuit using a Pro Series Dimmer?

What will be the result, if we mix different Types of light fixtures (for eg. 240V Halogen, LV Halogen with Leading / Trailing edge Transformers, in a single circuit, connected to the output of a Pro Series Dimmer?

What will happen, if we mix different Types of Lights eg. Halogen, Fluorescent etc in a single circuit and Try to dim?

Please help me to get some information on this, and the wiring of Dimmers.

Thanking you in advance.

Rakesh

 

Hi rakesh_k_v

The Pro dimmers are a Leading-Edge design, and are not suitable for Trailing-Edge dimmable transformers. You should use the new Univeral DIN dimmer (4 channels x 2.5 amp) for trailing edge.

For fluorescents, you will need to ensure that the lamps are dimmable... if it's linear fluorescent then as far as i know only Philips make a "dimmable" ballast (brand new model EBS-EasiDim).

Some retrofit compact fluorescents are dimmable, but you definitely should test and ensure you are happy with how they work. There is always the danger that the retrofit lamp accidentally gets replaced with a non-dimmable unit in future, which will cause mayhem and/or damage to lamp or dimmer.

Generally, for dimming fluroescent it's far better to use a proper controllable electronic ballast. For domestic use the Analogue 0-10V control system is most suitable, on commercial projects there are advantages in using DSI or DALI protocols.

Regarding mixed loads, it depends. I've never seen any problem mixing resistive (240V halogen) and inductive (leading edge) or capacitive (trailing edge) transformers, but there is always the chance that something will go wrong. You definitely cannot mix Leading and Trailing on one circuit.

But more importantly, why would you want to mix the loads on one dimmer channel? The whole idea of a control system is to wire loads separately so that you can create scenes etc. Wiring everything up to a single channel and dimming it together kind of negates the cost of a control system... you might as well just wire it back to a standard wall dimmer.

Regards wiring - each unit is supplied with wiring instructions, but it's basically Mains Power (active, neutral, earth) In, and dimmed Actives out to the loads. Wiring should be done by a licenced installer. What exactly did you need to know?

Cheers, JohnC

 

Hi

Thank you Mr.JohnC for your reply,

Need some comments on the following,

1. In our installation we are having Two Pendants (300W Halogen) and Two Spot (12V 35W Halogen) lights in one circuit. We are using Architectural Dimmers for the dimming purpose.

2. Does it make any problem in connecting 12V 35W Halogen Spot Lights and 12V 50W Halogen Spot lights in a single circuit? Does the wattage difference of the Bulbs make any problem.

3. Can we use the same Transformer for the 12V 35W and 12V 50W lights?

4. Can you please give Spec for the LV transformers which can be used with the Dimmers, so that we can connect 18 Nos of Lighting points in one circuit.

5. Lowest capacitance loading and VA rating that is available in the market.

Regards, Rakesh

 

Hi rakesh, In many of my comments below, I am making an assumption that you are working on a domestic project. If not then some of what I say will not apply.

OK - total load is about 680VA, + 20% safety margin = 3 Amps at 240V. You need a 5A dimmer channel for that. (see notes further below)

Not at all.

It depends on the transformer. Any DECENT brand of electronic transformer will be able to adjust to either load - typical rating of a cheap transformer is 20 to 60VA. So, generally the answer is yes.

18 points at (say) 60VA = 1080 + 20% safety margin = 1300VA = 5 Amps at 240V.

But you are missing the point. The WHOLE idea of a lighting control system is to have the ability to change the lighting scheme at a later time, to suit individual situations. This is setting "scenes", and it is the whole point of lighting control. If you hard wire everything to one circuit, and dim it all together you might as well just use conventional wiring.

If I had 18 x LV lamps, I would be connecting NO MORE than 4 per channel. Then I'd connect each to a 1A dimmer channel. That way, if I wanted to I could dim together, but retained the flexibility to dim separately if required.

For the 300W Pendants and Spot lights, those also should go on separate channels. Pendants on a 2A channel each, and the 2 spotlights on a 1A. Using smaller dimmers is usually cheaper than using a larger dimmer.

Remember - you cannot change the wiring easily once the place is built !!!

The MORE channels the better. If you cannot afford to buy the dimmers, and only want to have one switch per room, perhaps you should be hard-wiring the place, since you don't gain any benefit of something like C-Bus if you don't make it flexible.

It depends what country you are in. Here in Australia the Tridonic/Atco Speedy and Possum transformers have proven a reliable and cheap choice. The chinese-made transformers are usually a disaster, and considering the small difference in price you really should be buying "up to a standard" and not "down to a price". It's false economy to connect a $5 transformer on a $5 light to $20,000 lighting control system.

Note - low capacitance is not necessarily a good thing. Osram did tests on their new "Redback" transformer and found that too-low capacitance caused a wavering (slow change) in brightness setting at certain low dim settings. There have been reports that this happens with Possum transformers sometimes.

This may not be what you want to hear, but you should think carefully about how you are approaching the design. There is a reason why the most commonly used C-Bus dimmers have such seemingly low power outputs... it's because you shouldn't really be dimming much more than 1.5-2A per circuit if you want a decent domestic project.

Link to more info :

Heaps of info in this old thread, including links to charts and tables about transformers :
http://www.cbusforums.com/forums/showthread.php?t=1770

Formula to calculate transformers is on this page :
http://www2.clipsal.com/cis/technical/technical_support/newsletters_and_faq/transformers

 

Thank you for this informative reply...these points will help someone new to the Lighting control system and hope i can utilize at the max.
thanking you once again...
rakesh...