WYE to Double delta converting
WYE to Double delta converting
(OP)
Hi all
i has 3 phase wye connection 400V LL, 230V LN, 30KVA
i wanna make it single phase i read in the generator manual the best way to make it single phase is the double delta. my question is: when i make the connection double delta does this decrease the rating power
? or the generator will gives the same power when it was in WYE (3phase) connection.
3 phase wye power = 1 phase double delta power .... is that right ?
i has 3 phase wye connection 400V LL, 230V LN, 30KVA
i wanna make it single phase i read in the generator manual the best way to make it single phase is the double delta. my question is: when i make the connection double delta does this decrease the rating power
? or the generator will gives the same power when it was in WYE (3phase) connection.
3 phase wye power = 1 phase double delta power .... is that right ?






RE: WYE to Double delta converting
Unless the generator manual or spec tag specifically says the capacity is the same, you should assume the capacity is 20kVA single phase (2/3 of 3 phase capacity).
For many/most manufacturers, an "extended stack" is a special order option.
RE: WYE to Double delta converting
RE: WYE to Double delta converting
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If we learn from our mistakes I'm getting a great education!
RE: WYE to Double delta converting
Your current capacity will be the same.
Your KVA capacity will be 2/3 of the original rating.
You may run at unity power factor.
Your engine will have enough power to develop at least 120% of the allowed output for a standby set and over 130% of the allowed output for a prime rated set. Beware that you don't overload the set. There will be enough excess engine power available to damage the set if it is overloaded.
Bill
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"Why not the best?"
Jimmy Carter
RE: WYE to Double delta converting
You should have line 1, line 2, line 3 and a neutral.
Open the neutral connection.
Locate the conductor(s) that has continuity to line 3.
Connect this conductor(s) to line 2.
Insulate this connection.
Take single phase power from line 1 and line 3.
The neutral is still the neutral.
This reconnection may be done safely even if all the wire identification tags are missing.
This was once the preferred single phase connection.
The performance is the same as the double delta connection.
Note, you should be able to locate the neutral point and it is safe to arbitrarily assign line numbers to the three phase leads for the purpose of this connection.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: WYE to Double delta converting
I also remember when zig-zag was the preferred single-phase connection. Do you know why double-delta is now preferred?
RE: WYE to Double delta converting
Then there is the Collins or bar-diamond connection for converting 10 lead sets.
Of the two parallel windings, one has the zig-zag going up on the vector sketch and the other has the zig-zag going down. With the common neutral connection on one set of windings you can't use a double delta or conventional zig-zag to convert to single phase.
Bill
--------------------
"Why not the best?"
Jimmy Carter