Commercial voltage optimisation

[Tim]

Hi guys,

I am going down this afternoon (3pm) to look at a large supermarket that is having voltage optimisation installed (one of many more on a list) and the electrical firm doing it want to sub it out to company i work for. (The other company and mine have a long standing relationship of passing work across if they get busy)

There is a guy from the other company meeting us there to go through the project and i want to have a list of questions ready to make sure we are all clear on whats going to happen.

I have no experiance in fitting these devices, however i have read a bit about them.

Have any of you fitted these devices and if so did you have any problems? Can anyone see any potencial issues or recommend questions to ask?

All the details i have so far are that its a 'powerperfector' unit, there will be a gennie on site to take over while the unit is installed and it is going to be out of hours.

Thanks in advance for your help,
Tim

 

[Engineer54]

If I remember rightly some circuits where getting less than 220....

Pretty sure that was part of the problem...don't hold me to it though, was a few years ago.

If that ''Was'' the case, then the system was incorrectly set-up. As far as i'm aware, all the present voltage optimisation systems are based on providing a steady 380V 3 phase/220V single phase supply to connected equipments, that shouldn't be affected by increasing or decreasing loads etc.

 

[Brightspark2]

If that ''Was'' the case, then the system was incorrectly set-up. As far as i'm aware, all the present voltage optimisation systems are based on providing a steady 380V 3 phase/220V single phase supply to connected equipments, that shouldn't be affected by increasing or decreasing loads etc.

Volt drop?...

Set up or design. I doubt much is done. More approach client and say hey we can save you this much if you pay us this much. Then stick it in and move on. Money spinner. I won't tar everyone with the same brush though.

 

[westmac]

OK, I can understand the economic argument IF..... surely, a fixed resistance is a fixed resistance, and a watt is a watt, so if voltage drops then current rises....and a watt is a watt.... so how does this save energy?? (Allowing for us not talking about PF correction, of course). Tony has written up on this subject elsewhere and about the time he experimented dropping TX voltages at the MV level, and in effective the MVA dial didn't move! I'm genuinely interested, not spoiling for an argument!

If you're varying the voltage across a fixed resistive load, a voltage reduction will not result in a current rise. Fixed resistive appliances quote a power rating based on a nominal voltage, the resistance is the constant rather than the power consumption.

 

[Engineer54]

If you're varying the voltage across a fixed resistive load, a voltage reduction will not result in a current rise. Fixed resistive appliances quote a power rating based on a nominal voltage, the resistance is the constant rather than the power consumption.

In other words Rockingit, you'll just have to wait a little longer for the kettle to boil before you can have you're cup of tea/coffee!! lol!!

 

[Rockingit]

In other words Rockingit, you'll just have to wait a little longer for the kettle to boil before you can have you're cup of tea/coffee!! lol!!

Maybe. But the fridge that keeps the beer cool is on 24/7, so sod waiting for the kettle!

 

[Engineer54]

Maybe. But the fridge that keeps the beer cool is on 24/7, so sod waiting for the kettle!

And there was me thinking in terms of morning coffee's, rather than eveing beers!! lol!!

 

[Knobhead]

Motor loads will not benefit from voltage optimisation.

The governing factor is shaft HP. Lower the voltage and you’re heading for trouble!

 

[Engineer54]

Motor loads will not benefit from voltage optimisation.

The governing factor is shaft HP. Lower the voltage and you’re heading for trouble!

Most AC induction motors that i have come across, have always had at least a manufacturer's tolerance of 10% and often 15%!! Can't really see a voltage reduction of around 10 volts is going to make much of a muchness to be honest...

 

[Marvo]

If you want to improve motor efficiency surely it's better to run them through a vector drive inverter that ensures full saturation regardless of load and minimises copper and iron losses.