What is the Maximum Wattage Per Channel

Hi Everyone,
I am new to this C-Bus Forum.
This is my 1st ever thread.

About 14 Years ago my entire home was fitted out with C-bus.
The entire installation was professionally done at that time.

I am now in the process of adding Two garden lighting Channels.
Each Channel with 5 Halogen Lamps. Each Lamp 20Watts. Hence - Total Wattage per Channel is 100 Watts.
I want to run these two 5 Lamp Channels on a C-Bus "Dimmer" Module.

In the C-Bus cabinet there is a "Dimmer" Module. Part # L5508D1AP.
6xChannels are in use. The other two Channels are Empty.

I have:
10x Lamps at 20 watts each. [To be split into two sets of 5x20 Watts. Total 100Watts Per Channel]
2xTransformers. The Specs are: Tridonic.ATCO LVL8-2. Enclosed Transformer.
Input Voltage: 240V 50Hz. Output Voltage 12V a.c. Rating 200VA.
Output Current: 16.7A(Fused 30A) V99.
Code No: M120240012. AS/NZS 61558.

My Question now is
With "Dimmer" Module. Part # L5508D1AP
What is the Maximum Wattage Per Channel "Safely" Permitted on this Module.

I realise: Watts = Amps x Volts.
So Amps = Watts/Volts.
So is it: 100 Watts /240 Volts = 0.416 Amps per Circuit. [High Voltage Side]
OR is it: 100 Watts /12Volts = 8.333 Amps per Circuit. [Low Voltage Side]

So my understanding is that the Tridonic ATCO LVL8-2 can "Safely" handle up to 16.7Amps [200VA /12V = 16.7Amps] on the Low Voltage Side.

What I fail to understand is the relationship between the C-Bus "Dimmer" Module. Part # L5508D1AP and the Tridonic ATCO LVL8-2. The C-Bus information Sheet says - Maximum Incandescent Load per Channel = 1Amp. [Is this 1Amp on High or Low Voltage Side of Module]

In essence, I want to know if it is possible to run 5x20 Watt Halogen Lamps [Channel total 100Watts] with "Dimmer" Module. Part # L5508D1AP and the Tridonic ATCO LVL8-2.

Thanks in advance for your valuable advice.

 

Short answer. Yes.

Long answer. The rated 1 amp is the channel capacity. i.e. what the dimmer can deliver. Transformers transfer power, so the power stays the same (minus losses in the transformer). So the VA on the input is the VA on the output (again ignoring losses). So for your 100 watts you will draw approx 0.5A from the dimmer channel allowing for transformer losses.

Be aware that the dimmer you are using is leading edge and so must be used with iron transformers with that amount of load (i.e. not electronic). The LVL8 is an iron transformer so will be fine.

If you ever change the globes to leds you will have to rethink it.

 

Hi Ashley,
Thank you very much for your quick response.

Long answer. The rated 1 amp is the channel capacity. i.e. what the dimmer can deliver. Transformers transfer power, so the power stays the same (minus losses in the transformer). So the VA on the input is the VA on the output (again ignoring losses). So for your 100 watts you will draw approx 0.5A from the dimmer channel allowing for transformer losses.

I take it that you arrived at 0.5Amps … by dividing 100 watts by 240 Volts = 0.417Amps. Then allowing for losses rounded it off to 0.5Amps. Is my assumption correct. Please confirm.

Ok now if I wanted to "Upgrade" to 200Watts [5x40Watt Halogen Lamps] per Channel then the calculation would be: 200 Watts / 240 Volts = 0.833Amps. Then allowing for losses rounded off to 1Amp. At this point I am nearing the 1Amp rated capacity of the C-Bus "Dimmer" Module. Part # L5508D1AP. I plan on using the Tridonic ATCO LVL8-2 Transformer on this Channel. Please confirm my understanding on the above calculations.

Once I understand the "Calculation" side, I will be sweet on doing more upgrades elsewhere in my home.

Be aware that the dimmer you are using is leading edge and so must be used with iron transformers with that amount of load (i.e. not electronic). The LVL8 is an iron transformer so will be fine.
Thanks for this valuable information.

If you ever change the globes to leds you will have to rethink it.
Our home was completely C-Bus wired 14 Years ago.
The home has 3xC-Bus cabinets fed via 3 Distribution boards strategically located.
Each C-Bus cabinet consists of several Dimmers & Relays of varying capacities. Mostly ALL the Transformers are ATCO TM50's [Black Colour] and some ATCO LVL8-2. I am told that… these are "Iron Transformers".

Be aware that the dimmer you are using is leading edge and so must be used with iron transformers.
I do have another question for you but I don't think it is relevant to my "Original" thread posting.
Not sure… if I should ask here or create a "NEW" Thread!.
In essence. It's about compatibility. My Network… off the bat consists of approximately 120 Channels driving numerous Lamps and Power Sockets…

At a later stage… I want to "Upgrade" from Halogen to LED on about 5 to 8 Channels [Circuits] on different Dimmer Modules servicing my "Kitchen - Family Room & Dining areas". ALL Dimmers on my Network are "Leading Edge". What is the "Safest & Governing Body Approved" way on going from Halogen to LED for ONLY these 5 to 8 Channels [Circuits].

I say "Safest & Governing Body Approved". I will NOT deviate from these conditions and will NOT jeopardise the Safety of the home.

Upgrading an entire home of this size to FULL LED would be cost forbidden.
I am retired and short on Dough.

Thank you.

 

Correct.

Correct. 200W is a good limit for the 1A dimmers when using quality transformers.

There are two issues with replacing Incandescent with led lighting. Firstly the majority of leds use electronic transformers which have a capacitive input rather than inductive which leading edge dimmers don't like. A dimmer will have a rated capacitive load and a good led driver will give you its capacitive input, so by adding up all the driver inputs you can ensure it is within the dimmer limits. Not heeding this can destroy the dimmer. Secondly, dimmers have a minimum load rating which can be an issue if you are only driving a few leds. This won't hurt the dimmer but can result in the led flashing when powered off and poor dimming performance.

There has been lots of discussion on these forums about led lighting. Just search for them. Good quality leds designed for leading edge dimmers will work fine. Cheap Chinese ones won't

 

Hi Ashley,
I will now run with the 5x40W = 200Watts per Channel on the L5508D1AP Dimmer & Tridonic ATCO LVL8-2.
Perfect. Thanks for this information.

Whilst I now know how to do the calculation…. I still do NOT fully understand the "Principles" of electricity here.

So Please pardon my ignorance in advance on the following question.
I am only trying to understand the "True Concept" a little better.
Long answer. The rated 1 amp is the channel capacity. i.e. what the dimmer can deliver.
Ok understand.

Transformers transfer power, so the power stays the same (minus losses in the transformer).
When you say "Transformers" is there a transformer inside the "L5508D1AP" Dimmer as well..??
OR are you referring to the Transformer "Tridonic ATCO LVL8-2" ONLY.

So the VA on the input is the VA on the output (again ignoring losses).
When you say "VA on the input is the VA on the output" is this on the L5508D1AP Dimmer or on the Tridonic ATCO LVL8-2 …. OR Both units??

So for your 100 watts you will draw approx 0.5A from the dimmer channel allowing for transformer losses.
To arrive at the 0.5Amps. We go 100Watts / 240Volts = 0.416Amps.
Then allowing for losses rounded it off to 0.5Amps.

The stamping on the Lamp Globes say 12V-50W.
The downstream 100Watt total is on the 12V AC Side.
Yet we go 100Watts / 240Volts = 0.416Amps… Rounded to 0.5Amps current draw at the "L5508D1AP" Dimmer.

Can you please explain me why it is so.
To me there appears to be a "Linear shift" in Power from Upstream 240V AC to Downstream 12V AC.

Thanks in advance.

 

The Tridonic transformer.

Both. Power doesn't change apart from losses.

Yes.

What linear shift? The lamps draw 100 watts, the dimmer supplies the 100W (and the dimmer draws 100W from the mains assuming only that channel is active). If you change the voltage you change the current in inverse proportion. Power stays the same.

 

Hi Ashley,
The lamps draw 100 watts, the dimmer supplies the 100W (and the dimmer draws 100W from the mains assuming only that channel is active). If you change the voltage you change the current in inverse proportion. Power stays the same.
Very well explained.
Now things are "Crystal Clear" to me.
A big thank you.