GHL dimming problem - help!!

Hi, i'm due to go on holiday in a few weeks and my GHL controlled lighting has developed a problem!

I have a 8 x 54W dimmable ATI powermodule connected to my GHL by an EVG-AP-2F.

Channel 1 controls 2 lamps (1 ballast) and fans

Channel 2 controls the remaining 6 lamps (3 ballasts)

Channel 1 works fine with no problems, however when channel 2 dims to 0V, the relay does not switch off.

I have tried tracing the problem by doing the following when both channels are at 0V and therefore all lighting should be off:

1. Cutting the power - kills all lighting (of course ;)) but when reinstated channel 2 re-illuminates at minimum illumination - no reaction from relay.

2. Unplug the control lead from the GHL - result is that channel 2 brightens to 100%. When this is plugged back in it dims back to its minimum setting. No reaction from relay.

Now this is where it gets strange -

3. Disconnect one of the channel 2 ballast control cables from the EVG - this brightens the lighting to 100% as it should when the controls are removed - however when it is re-connected, the relay shuts off, thereby switching off the lighting as it should :confused:

The lighting then works normally for the full cycle the next day. At first this was happening maybe once a fortnight but has now started to happen frequently. i need to fix it ASAP so i can confidently leave it whilst i am away!!

My suspicion is that i may be frying the relay as it is powering 6 x 54W lamps but it is rated at 16Amps, and the lighting should only be pulling 2 Amps at the most :confused:

Please can someone help!

Thanks.

Hi,

the relays of the EVG-AP can only drive 1 or 2 ballasts (per channel), otherwise the inrush current (current when switching on) is higher than 100A and then the relay contact stick together.
The contacts may release after vibration and work again - until the next switching on.

Solution:
- use more EVG-AP and divide the current
- use a EVG-AP-HIC (special version for High Inrush Current)

Thanks very much Matthias, you have basically confirmed my suspicions.

I'll order the HIC version as a replacement.

I have a question on why I am not seeing 10 volts on the dimming circuit when at 100%. I am only getting 9.7volts.

Any suggestion on why this is?

this is possible due to tolerances but no reason to worry, most 1-10V-interfaces have their full power already at 9.5V

Thanks for the information. That is good to know.