External Generator Voltage Spikes

Hi All, first post so be gentle - I'm not an electrician ...

I live in an area of Western Australia where the power frequently drops out. A while ago I bought a small (7kVa) 3 phase/single phase generator to use when the lights go off. My house receives 3 phase power and this is balanced out in the DB. A friend who is an electrician wired the DB for the generator and provided an external 3 phase socket so that I can attach the generator. In testing I switched off the mains power and switched on the generator. All seemed to work fine for a short while and whilst I was monitoring the line voltage, it dropped to just over 200v and peaked at 253v (Australia uses 230v). This caused a problem in that all the CFL bulbs in the house blew at the same time and I suspect many of the other appliances heaved a sigh of relief when I switched back to mains power. I'm not sure why the voltage changed so much during the test. I have the usual fridge, computer, hifi things like most households and know these switch on and off regularly.

So, my question - is there some sort of line conditioner I can use to stop this happening? It would need to happen before the DB.

Incidentally, this is a link to the same generator I bought:

Diesel Generator Silenced 8 KVA 3 Phase Single Phase | eBay

Thanks in advance.

Bill.

 

Welcome to the forums.

Why do you have three phase service in your house ?
A three phase line conditioner would cost more than that generator.

Mains power is nominal 10% So that would be 207-253. That sounds about what your generator is doing. You might want to contact that company and find out if there's a way to set it for tighter regulation.

 

Hi PJmax - thanks!

The original builder of the house had three phase power installed as there was a business run from the garage and I suspect they intended to use large compressors etc requiring 440v.

Interesting that there's a three phase line conditioner available - is there any info I could get on one? I appreciate that there's a cost involved, I've come a long way to back out at this stage....

Thanks again.

Bill.

 

What is the capacity of your generator at 230V 3ph? Maybe 30amps? Is it possible you overloaded the generator? You day you have the normal stuff in your home but do you have air conditioning or something that would have thrown a large load on the generator. If you did overload the generator then it's likely it could not regulate the voltage correctly. I did not see at connection for 230V three-phase on the site you listed, only three single-phase receptacles and the statement that the load must be balanced. I did not see an owners manual. Do they show using the three 230V receptacles for a three-phase service? If you are within the generator capacity it should regulate the voltage correctly.

 

Yes, I do have aircon but didn't try this during the test. I had a look at the link and it should have linked to a "DIESEL GENERATOR SILENCED 8 KVA 3 PHASE SINGLE PHASE" which shows the three single phase and one three-phase 20A 415v outlet. I've only used the three phase socket on the generator so far. I'll try and track down and owner's manual for clarification.

many thanks.