Generator Reconfigure 1

[Gen15]

I am working on an older Generac generator for a customer who is going to use this unit in a different application. The voltage is 208/120 parallel wye. I am going to change it to 240/120 double delta. The gen is a 1998 trailer unit and I have not found any resources on a reconfiguration for this gen end. The windings are not labeled NEMA standard. I have tried mec alte drawings because they were numbered the same as mine but I had to shut it down as soon as it excited because the engine loaded up. I've tried Generac's achieves but with no success. Any help in identifying my windings would really be a help. I have attached a data plate for the gen and a crude drawing of my original configuration. The 12 leads were numbered as they appear on the drawing. My model number is 98A03931-S. My serial number is 2042813. My windings are 1-2, 3-4, 5-6, 7-8, 9-10, 11-12. This is far from Generac's normal of 1-4, 2-5, 3-6, 7-10...... Any help would be appreciated.

 

[waross]

READ MY LIPS
YOU HAD A NEUTRAL BAR.
THAT IS STILL THE NEUTRAL BAR.
IT HAD SIX LEADS ON IT AND WAS THE NEUTRAL BAR.
YOU REMOVED TWO LEADS BUT THE OTHER FOUR LEADS ARE STILL THE NEUTRAL BAR.
YOU CONNECTED THE TWO LEADS THAT YOU REMOVED TO TWO OTHER LEADS. THAT IS NOT THE NEUTRAL. TAPE THAT CONNECTION AND FORGET IT.
THE ORIGINAL NEUTRAL IS STILL THE NEUTRAL.
MOST PEOPLE DON'T EVER SEE THE 208 VOLTS BECAUSE THEY FOLLOW THE INSTRUCTIONS AND TAPE UP THE ONLY CONNECTION THAT WILL SHOW 208 VOLTS.

 

[Gen15]

Sir . I UNDERSTAND!!! I restap with every storm or flood from NC to Florida and as far west as Texas. I'm measuring at the end of a 40" power generation cable. The neutral is tied to the said neutral bar. This gen was L1-N 208 and L2-N 120. 240 L-L. An engineer at a rewind shop explained to me before I changed it the final time. If I grab the start of a winding instead of a stop it gives you a different result . His guess was a low voltage but my result was a high voltage. I turned those 2 windings over and got the proper voltage at the end of my cable in double delta and zig zag. What ever you make of that is up to you. Thanks for your input. I learned alot. By the way my isolated joint was connected with with 4 wires and 2 jumper bars on a terminal strip. Neutrals were isolated on a bar. No chance of confusing those two. I wish I knew who manufacturered this end for Generac. If you have any thoughts on what made it work by flipping the windings, let me know. I enjoy learning! Just for the fun of it when the voltages were off I measured from my isolated joint instead of neutral. The 208 just swung to the other line.

 

[waross]

208 Volts is normal and to be expected on one wire pair. That's why you tape it up and forget it.

Just take the neutral end of one winding and connect it to the hot end of either of the remaining windings and tape up that connection.
Was my explanation that bad?
It is the simplest and most forgiving reconnection for three phase to single phase imaginable.
Voltages;
L1 to neutral. 120 Volts
L1 to l3, 240 Volts
Neutral to L3, 120 Volts
L1 to L2, 208 Volts; tape this up and forget it.

 

[Gen15]

It must be my explanation. We did that 2 out of the possible 6 configurations and both produced the same voltage. I had an electrician watch me and I sent you the drawing of how I connected it. I also had an engineer from a motor shop in Louisiana go over it with me just so I could say it out loud and we both looked at my sketch I sent you. It was still bad voltage. There is no possible way to check voltage from the wrong joint on this unit because there is no taped joint. All in all it's on the job site working with a set of windings flipped. Thanks

 

[waross]

You didn't tape up the proper connection.
If you had done it properly, you would not have been able to see the 208 Volts as that should have been taped and forgotten.
If you insist on making something so very simple into something complicated, I can't help you.
You read 208 Volts from a connection to L1. Tape up that connection and forget it.
Read my lips.
208 Volts on the new connection is normal.
That's why you TAPE IT UP AND FORGET I.
THE 208 VOLT CONNECTION IS NOT USED.
IT IS THE WRONG VOLTAGE AND THE WRONG PHASE ANGLE.TAPE IT UP AND FORGET IT.
By the numbers, if the numbers are correct.
Line 1 = #1, #7
Line 2 = # 2, #8
Line 3 = #3, #9 Note: There is 208 Volts between L1 and L3.
Neutral = #4, #5, #6, #10, #11, #12.
Line 2 neutral is #5, #11.
Disconnect #5 and #11 and connect them to line three. Surprise! There is still 208 Volts between 1 and L3. TAPE IT UP AND FORGET IT.
Now you will have 120/240 Volts single phase left.
Pick one line, find the neutral ends of the windings with a continuity tester and remove those leads from the neutral bar and connect them to either one of the other lines and TAPE THE DAMM THING UP AND FORGET IT.
There will always be one connection showing 208 Volts. This is not used and is taped up and forgotten.
This may be done quickly, safely and easily with a continuity tester and does not depend on the numbers.
If you had followed instructions and taped the connection up before you started taking voltage measurements, you would have never known about the taped up and unused 208 Volts.

 

[davidbeach]

Ah, come on Bill, how do you really feel about it?

 

[waross]

Were my instructions really that bad, David?
Time for tough love.
Thank god it wasn't a ten lead machine needing a bar-diamond connection. (Still possible with a continuity tester and no numbers.)