single to three phase converter for 2391 practical practise board

[amateursparky]

For 2391 I will be testing a three phase distribution board with a motor and single phase sub main.

I am finding it hard to memorize the test procedures. So for me it's about repetition but naturally I don't have a three phase supply at home.

I want to buy a clarke pc60 three phase converter.  Now AFAIK for the the single phase sub main to work I would require a neutral because single phase loads aren't balanced or something like that. It's been a while since I studied three phase theory.

The converter only has a 4 pin TP and earth plug so no neutral. I just wanted to check with people more knowledgeable, can I just run a neutral separately from the wall socket feeding the converter? I don't see why not because it's the same bloody supply

I might even be able to do it internally for a cleaner install but I have to return the sucker afterwards so I can't be taking it apart.

 

[Andy™]

they dont usually give a true 3 phase output so probably not all that much use for your intended purpose

 

[apprentice87]

Ok,, I take it that what you are trying to do, it to "make" a three phase supply so you can experiment round a bit?? One of them converters will be no good at all. I know you think you plug the thing in the wall and "three phase" come out the other end, but IT DOES NOT..

What basically happens is this...

The single phase supply enters the contraption, goes through a transformer to raise the voltage. Next what is connected to your motor, is the SINGLE PHASE phase conductor, to say L1, the SINGLE PHASE neutral to say, L3. Inbetween L1 and L3 there will be some capacitors [yep connected across the supply] From the centre of this capacitor bank, a connection is taken to L2..

IF you have selected capacitors of the correct size, you will have an "artificial" phase generated BY THE MOTOR ITSELF, and the thing will run quite happily [once you have got it started that is..

So, no, you cannot just use one of these things in the way you want..

I cannot understand why lots of people claim to be electricians, but seem totally confused by a three phase supply?? How does it differ from a single phase one?? just another two phase conductors?? Nothing complicated about it at all..

Now the exam thing you are doing i have never done, but all the IR testing and continuity testing will be the same principle. You need to know the various voltages between the phase conductors and neutral AND earth, so as to be able to identify each conductor correctly, and you will need a phase rotation meter as you will presumably need to check phase rotation is correct..

The other will be able to advise better, as i am not qualified at this sort of thing...

john..

 

[Tony S]

Have a look at

 

[Sidney]

When testing three phase just treat it as three single phase supplies, only difference being your PSSC test either needs to be done between phases, if your test meter can handle it, or double your highest L>N measurement.

Doubling is the rule of thumb method, for the more precise one multiply your highest L>N measurement by 1.732.