three phase to single reconnection 3

[liam357]

Hi all,
I want to reconnect a three phase generator to single phase 240v 50 Hz to get the most Kw on one connection from this. It is a Kato (12 lead) 11Kw generator. I attach a hook uo diagram, please have a look at this and recommend the best one to use Many thanks for your help.

Liam

 

[waross]

The zig-zag connection is often the easiest to connect in the field particularly if some wire markers are missing. The double delta connection is most often used when the set is factory configured for single phase.
You will get 2/3 the KVA and the max kW will equal the KVA (power factor unity). The prime mover will have enough power to overload the generator end.
What voltage is the set configured for presently?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[liam357]

Bill,
It's on 240v. All 12 wires are numbered. When you say double delta does this mean series delta? Have you come across 10, 3 wire, parallel dogleg connection before ?
Thanks
Liam

 

[ccjersey]

If "10" means single phase, then yes, the parallel dogleg is the most often used single phase reconnection of a 12 lead generator end.

Double delta is another single phase reconnection which produces the same 120/240 single phase. Series delta is a 3 phase reconnection that produces 120/240 3phase 4 wire power. It has a neutral tapped into the middle of one side of the delta so you can have 120 volt circuits by connecting to 2 of the lines and the neutral instead of just 240 between the lines.

I am wondering if you will be able to use more than 1/3 of any of these generator windings for your 240 volt 50 hz power. What kind of distribution panel do you have? How many lines in? How many are "hots"? Is one a neutral?

 

[ccjersey]

Did you notice that the same reconnection plan is called both "zigzag" and "dogleg"?

As you see in the diagrams, there are 2 types, the "low" or parallel which usually produces 120/240 single phase and the "high" or series which produces 240/480 single phase.

 

[waross]

I see more and more new sets coming out with the double delta single phase connection.
But you may use:
Zig-zag/dogleg.
Double delta.
Series delta and tape up the wild leg.
The single phase KVA is 2/3 of original in all cases.
A common conversion here is from 120:208 V three phase to 120:240 V single phase.
To use the zig-zag connection, the conductors of one winding end may be removed from the neutral connection and connected to the hot end of either of the other two windings. This connection is insulated. Given phases "A", "B", and "C", if you move the neutral end of "B" phase to the hot end of "C" phase, then you will have single phase from "A" to "B". This is simple and may be done with a continuity tester even if all the number leads are missing or illegible. I prefer this conversion for field modifications for this reason.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ccjersey]

If your 240 volt 50 hz single phase supply has one line grounded (a neutral) and one line ungrounded , then you will have to ensure that the neutral point of the single phase reconnections shown above is "floating" before you can ground one of the generator lines for the 240 volt 50 hz neutral.

 

[nawao]

liam 357,
For single phase zigzag connect:
3 - 9 - (L1)
6 - 1
12 - 7
4 - 5 - 10 - 11 - (M)
2 - 8 - (L2)
Voltage L1 - L2 : 240V
Voltage L1 - M : 120V
Voltage L2 - M : 120V

 

[liam357]

CCjersey,

I need to be able to start a 2200 kw motor. Otherwise a sub panel would work but balance may be an issue. Not sure what meant by Low and High on diagram.

Thank you.
Liam

Bill,
Looks like 2/3 of power is the best I will get here. On hook up diagram the 10,3 wire, parallel dogleg, L4 being neutral, do you know what way L1 and L2 would be connected?
Thank you,
Liam

 

[liam357]

Nawao,
This is a 11KW generator, what KW would I get on your hook up plan? I will use this as standby for my house, is M neutral and can ground be connected to M?

Thank you,
Liam

 

[ccjersey]

Your thread has taken a "hobbiest" turn. It may disappear from this forum, so here is a link to a more appropriate site where you can get lots of help.

http://www.smokstak.com/forum/forumdisplay.php?f=6

 

[nawao]

Liam,
You will get about 7.5 KVA.
(M) is middle point. To be used only if there are 120V circuits to feed. In this case you can ground it.
For 240V use the neutral will be one of the lines (L1) or (L2). Be careful to isolate the generator from the grid. Use a change over switch.