Thanks fellows ! UK distribution now makes sense.
Frank i tend to be always a paragraph behind any conversation. I have grown accustomed to it though.
Okay - so they've already confirmed they will accept 240 between L1 and L2 with one side 'grounded'( i prefer term 'earthed') . That's very sensible of them.
So the converter should be happy connected to your supply, 240 single phase one side earthed.
What is the significance of the output being delta only?
Draw yourself an equilateral triangle with sides 2.4 inches long.
Label the three vertices T1 T2 and T3 .
That's a scale drawing of your three phase voltage, 100 volts per inch.
Now observe from installation manual's block diagram on page 1 (page 4 of PDF) that:
T1 will be connected by the contactor to L2; and
T2 will be connected to L1; and
T3 will be created by the electronics .
T1 and T2 are 240 volts apart, that's defined by input L1 and L2.
T3 is placed by the electronics equidistant from T1 and T2. The electronics places it 240 volts equidistant.
Notice there's no neutral or ground. The gizmo doesn't really need them, it would work in an aircraftcraft or on the moon.
So now add to your triangle an Earth connection at , say L2.
Nothing really changes so far as the converter's electronics are concerned.
Your motors will see T1 "earthed", but they won't care so long as their insulation is sound.
Now back to your triangle
Now add arrowheads so that the triangle looks like it's rotating CCW.
Now our graphical representation of the 240 three phase voltage has become a "Phasor diagram".
All that means is the arrows now indicate phase angles of your three voltages by their direction on the paper.
Now locate the center of your triangle/phasor diagream, the point in middle equidistant from all 3 vertices.
IF there were a neutral that's where it would be.
The Phaseperfect folks did not bring out a neutral, in fact may not even have fabricated one internally, so there just isn't one.
That's the only significance . If you need a neutral you have to make it yourself.
........
Now if you wish draw another phasor diagram with sides 4.15 inches long.
That's utility power. They hand to you one phase and neutral as you have already described.
By grade school geometry you can show that distance from any vertex to neutral will be 4.15/√3 = 2.4 inches.
So your Phaseperfect converter will hand you a three phase triangle, 240 volts per side with one vertex earthed instead of its neutral earthed.
That should be just fine for motors. On low voltage connection they'll be wound delta anyway.
If you have a high inertia load like a planer you might start it first.
I apologize for the length of this post. I think in pictures and words come with great difficulty. But i try to paint a picture in listener's mind. If I've meandered offtrack please call me out on it.
Sophie - you are better with words than i, if you improve on this i'll be honored.
Probably there's a ten word answer just it didnt come to me.
old jim
