Delta fed WYE xfmr

[tshea]

Figure this out, I can't, and it is not bad meters.
#1 We have a 45kva 480 delta-208/120 Wye transformer being fed with a 240V 3? 3w delta grounded B (corner grounded system) on the low voltage side to get 480 3? 3w.
The output is 487V. My math says it should be approx 540V (13.3% higher than 480, since 240 is 13.3% higher than 208).
Actually reading was 487 checked with 2 different digital meters.
#2 What happens when when you "bond from X0 to building steel? (Answer SMOKE!)

We replaced the transformer with a delta-delta unit.
I don't understand why the voltage was 487?

 

[coulter]

Re: Delta fed WYE xfmr

Originally posted by tshea:
... Actually reading was 487 checked with 2 different digital meters. ... I don't understand why the voltage was 487?

Tap settings?, Primary voltage (240 feed to 208 input winding) low?, Both?

Originally posted by tshea:
... #2 What happens when when you "bond from X0 to building steel? (Answer SMOKE!) ...

This is a good thing, The laws of God and physics are holding.

carl

 

[tshea]

Re: Delta fed WYE xfmr

Don't know where taps were set.