Convert Generator to Double Delta?
Convert Generator to Double Delta?
(OP)
Hello, long time reader, first time poster to the forum.
I have a small 25kva Generac generator that I have installed at a transmitter site, when it was installed the unit was wired as a 4 wire delta to provide single phase 120/240v service to the building. The high leg is insulated and unused.
I was talking with a friend about this configuration as I maintain another unit at different location that is wired double-delta from the factory for single phase 120/240v usage.
My first question is, can any 12 lead generator be converted to double delta? There is nothing in the manual that shows a DD configuration as an option, I don't want to risk damaging the unit. There is a diagram for a zig zag configuration but it's listed for 85 - 200kW units, not for this smaller unit.
Second, the unit seems to operate properly as currently wired but a person voiced a concern as to whether operating long term with only a load across two legs of the delta might cause harm to the stator.
Thanks
I have a small 25kva Generac generator that I have installed at a transmitter site, when it was installed the unit was wired as a 4 wire delta to provide single phase 120/240v service to the building. The high leg is insulated and unused.
I was talking with a friend about this configuration as I maintain another unit at different location that is wired double-delta from the factory for single phase 120/240v usage.
My first question is, can any 12 lead generator be converted to double delta? There is nothing in the manual that shows a DD configuration as an option, I don't want to risk damaging the unit. There is a diagram for a zig zag configuration but it's listed for 85 - 200kW units, not for this smaller unit.
Second, the unit seems to operate properly as currently wired but a person voiced a concern as to whether operating long term with only a load across two legs of the delta might cause harm to the stator.
Thanks






RE: Convert Generator to Double Delta?
You should be able to use any generic DD connection diagram.
If there is any doubt about the numbers on the leads leave it as is. It is not that important.
The only real reason to change would be if you had a single phase load that exceeded 1/2 of the rating of the set. Then you would reconnect the set as 120 Volt delta.
When I have to reconnect a set I will generally use the double delta connection, but if it is already connected 4 wire delta I don't waste time changing it.
respectfully
RE: Convert Generator to Double Delta?
I know you lose 1/3 of the KVA rating when converting from 3ph to single phase, but I'm trying to understand what the electrical benefit is by changing from a single delta to a double delta. I'm having difficulty understanding the difference because you still have L1 to N and L2 to N each across an individual winding, so how does separating the single delta into two delta's improve things?
As a sidenote, the leads are well labeled on the unit, it's marked not only the insulation but with wire labels at the terminals too.
RE: Convert Generator to Double Delta?
What I meant to say, is what is the electrical difference in having one large delta configured winding compared to having two smaller deltas?
Does this better distribute the circulating currents in the windings and lower the overall operating temperature of the stator?
RE: Convert Generator to Double Delta?
respectfully
RE: Convert Generator to Double Delta?
:)
RE: Convert Generator to Double Delta?
Don
RE: Convert Generator to Double Delta?
respectfully