Voltage Optimisers.

[kitlearie]

Has anyone come across a phase sequence fault when switching on a voltage optimiser for the first time. The system is a cheap chinese one I think with terrible instructions.

Can a voltage optimiser know if your input wiring is black, grey, brown instead of Br, Bl, Gr? I ask because we don't want to have to reverse the wiring on hundreds of 3ph motors on site.

Any ideas why we might be gettiing the phase sequence alarm?


thanks


Kit

 

[kitlearie]

I hope your right. But I can't help feeling a change in phase sequence could make motors spin the wrong way.

thanks

 

[Guest111]

any change in phase sequence will change motor direction, think this way if at moment you have for example blue to l1 red to l2 and yellow to l3 at source and everything runs right way then connect red to l1 yellow to l2 blue to l3 from incomer to optimiser then out of optimiser connect l1 to blu phase l2 to red phase and l3 to yellow phase, optimiser should work and motors should run right way.

 

[Knobhead]

Reverse the input and the output to match.

What size is this optimiser? 1000’s of drives you should be looking at an on load tap changer transformer.

I worked for over twenty years on plants where the 11KV feeds were reversed. 18MW running without problems. (Two OLTC 33/11KV 10MVA transformers quite happily running “forwards” feeding the plants “backwards”).

 

[kitlearie]

The optimiser is 600amp. Big sod, weighs a ton - I mean literally one ton.

thanks

 

[Knobhead]

Here have a look at this

View attachment 11479

 

[spark 68]

I said back in #7,
there is nothing stopping you feeding the optimiser with the sequence 1-2-3 to suit just that unit, as long as you match the outgoing connections the same way, and then your original phase sequence will stay the same, whether it is CW or CCW, as long as the in's and out's match.

Think if it was just an Isolator that you were fitting.

What Iam trying to say, is whatever cables you need to swap over at it's incoming side to suit the unit and keep it happy, you swap over the same cables at the outgoing side, then your phase sequencing will be the same as it always been.

 

[Knobhead]

I’m giving up on this.

 

[kitlearie]

You are totally right. I just posted thanking all the help I got and explaining what we did to resolve the issue - exactly what you suggested!

ta

Kit

 

[Knobhead]

You took some convincing.

 

[a1guvner]

Ditch your 30k unit and get 3sp Vphase units and all your troubles will go away, Honest