VT Specs
VT Specs
(OP)
We have phase VTs whose specs is:
Primary Volts: 4200/7280GY
Secondary Volts: 120V
Winding Ratio: 35:1
Freq: 60Hz
ABB Model: VIZ-75, 7525A71G02
The vendor drawing shows that these VTs are connected in Wye grounded/Wye grounded on a 7200V, 3 phase buses.
The way I understand the specs is that each VT will have a 4200V Pri and 120V secondary. Connecting them in Wye-wye (both pri and sec neutral grounded)will yield 7280 phase-phase primary and 208V phase-phase secondary.
Is my understanding correct?
Primary Volts: 4200/7280GY
Secondary Volts: 120V
Winding Ratio: 35:1
Freq: 60Hz
ABB Model: VIZ-75, 7525A71G02
The vendor drawing shows that these VTs are connected in Wye grounded/Wye grounded on a 7200V, 3 phase buses.
The way I understand the specs is that each VT will have a 4200V Pri and 120V secondary. Connecting them in Wye-wye (both pri and sec neutral grounded)will yield 7280 phase-phase primary and 208V phase-phase secondary.
Is my understanding correct?






RE: VT Specs
So with exactly 7200.00 V primary, phase-phase, you would have 4157 V or thereabouts phase-ground. 4157/35 = 118.8 V secondary phase-to-ground.
Secondary phase to phase = 118.8 x 1.732 = 205.7 V
Check my button pushing, but you get the idea. The PT doesn't know what is on its nameplate. It just steps down the applied primary voltage by a factor of 35, or very very close to that.