I have a 277/ 480 vac Wye supply feeding a 15kva, 480 delta primary to a 400 vac wye secondary. This transformer will supply a 400 vac 3 phase machine. My question is for the 400 vac wye secondary. When I bond the xo tap to ground, I will not need to run a neutral to the machine correct? I will run a equipment ground the machine for ground fault protection.
Transformer Wye Secondary
- Thread starter curious23
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
Welcome to the forum.
Correct. The neutral need go no farther than the first secondary OCP/disconnect.
Correct. The neutral need go no farther than the first secondary OCP/disconnect.
- Location
- New Jersey
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- Journeyman Electrician
Yes as Larry stated you would still install a SBJ from the X0 to make this a grounded system. You would also need a GEC.
If the neutral is bonded within the transformer does it need to be brought out to the disconnect or would a SSBJ be all that's required?
Flicker Index
Senior Member
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- Pac NW
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What is the machine? 400v suggests it's from Europe or Asia. If motor is the main piece, 480v/60Hz into a 400v/50Hz motor would be just the right voltage with the correct VHz ratio as if you're running at at 120% speed on a VFD... and that's exactly what's going to happen if it's a 50Hz equipment.
I can't tell you whether or not you run neutral to the machine. That depends on if the machine utilizes 230v between L-N (assuming it's 400Y/230 Euro/Asian equipment). Whether 1.2x RPM would be acceptable for proper operation is something you ought to do in consultation with the factory rep.
I can't tell you whether or not you run neutral to the machine. That depends on if the machine utilizes 230v between L-N (assuming it's 400Y/230 Euro/Asian equipment). Whether 1.2x RPM would be acceptable for proper operation is something you ought to do in consultation with the factory rep.
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