Volt Drop

[Inteificio]

Hi,

I am working on a unit with a large compressor and lighting on a single phase (bad design).

When the compressor kicks in we get a volt drop noticeably dimming the lights.

This is not acceptable so am trying to a work a solution.

My preferred is just get everything on 3 phase, but not allowed here.

My other thought was there has to be something in the market that is designed for this.
Led drivers are normally switch mode with a cap reserve. That has a voltage drop though.
I suppose transforming the voltage up, then doing something like that to drop it down again...

Anyway, does anyone have any suggestions, I am stuck with 230v bulbs and a slight V drop for up to 30s every ten minutes.

Thanks,

P

 

[Inteificio]

Submain is probably fed off a 30m run of 6mm. Can't remember the total size, but probably a 40A or a 63A.

 

[Inteificio]

I should mention I cannot modify the system before the sub... to long to explain fully why. Short answer, this install is mobile.

So if anyone has any cunning ideas, they have to be implemented after.

 

[Engineer54]

Are you saying this installation is on a plug and socket ??

 

[Marvo]

Submain is probably fed off a 30m run of 6mm. Can't remember the total size, but probably a 40A or a 63A.

I should mention I cannot modify the system before the sub... to long to explain fully why. Short answer, this install is mobile.

So if anyone has any cunning ideas, they have to be implemented after.

The 6mm supply sounds undersized to me. If (you haven't shown any definitive test results yet) that's what's causing the volt-drop with the compressor start current and you say you can't upgrade it then your hands are tied.

We're back to the options of a UPS on the lighting circuit or a soft starter on the compressor. You previously stated these options are outside of your price budget so it looks like check mate to me. I'm all out of options that would cost less than a UPS. I did some digging around and Maplin have a selection at under 100 quid. Just a thought but if you go with a UPS this light circuit might fall under emergency lighting regs and I think there's a few requirements about this in the UK regs....

 

[Inteificio]

"Are you saying this installation is on a plug and socket ??"

Yes, a very big one.

Marvo, good point about the emergency lighting regs, didn't think of that.


So we may be stuck, shame!

looks like a last minute bodge is not going to fix this and back to drawing board.

 

[Marvo]

Sorry abuot the double post, bad forum etiquette I know.

I just read the thread again from the beginning and I'm concerned about how vague you're being. You say you designed the electrical installation but you aren't sure what size the feed into the panel is. You haven't come back to us with an actual spec for the compressor or the lightng circuit and you haven't given us any hard and fast test results regarding circuit impedences or on-load volt drops across the individual circuits or at the main incoming supply.....

You're really going to have to up your game if you want help and ultimately to find the problem and remedy it.Please please come up with some accurate specs and test results!!!

 

[Inteificio]

Hi Marv,

I am being vague as a lot of the design I have no control over.
The device is movable, so the feed will change. It has already been moved to another site, so I will probably never see it again.

I was vague as I wanted the advice to be general as I know I will come across this situation again.

I guess the question I phrased was too specific.

My question should have been:

If a large load on a circuit is causing the lights to dim, what cunning solutions can there be to fix it!


UPS seems a good idea, but will add unreliability, expense and potentially new regs to abide by.
The power regulator (ups without a battery), might be another solution.
Switching to a lower voltage lighting system that has a switch mode power supply in could be another idea.
Adding an extra phase would be the simplest and most reliable, but not always feasable.