If you have a service to a building that is feed from a Transformer that has a 4160v DELTA primary and a 480/277v WYE secondary. Then you set a second transformer 480 primary/ 208/120v secondary WYE to pick up your small loads and recep., is the Primary of this second transformer connected DELTA or WYE?
Transformer Connections
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websparky
Senior Member
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- Cleveland, Ohio
Re: Transformer Connections
Delta
Delta
ron
Senior Member
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Re: Transformer Connections
Which ever you choose. Just buy the correct transformer.
Which ever you choose. Just buy the correct transformer.
charlie tuna
Senior Member
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- Florida
Re: Transformer Connections
normally it's a delta-wye - on the 480/208/120 transformer.
normally it's a delta-wye - on the 480/208/120 transformer.
ron
Senior Member
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- New York, 40.7514,-73.9925
Re: Transformer Connections
dereckbc,
You are correct. Typically delta-wye for the 480-208/120 transformer.
Wye-wye is an odd selection, but it would work too.
dereckbc,
You are correct. Typically delta-wye for the 480-208/120 transformer.
Wye-wye is an odd selection, but it would work too.
Re: Transformer Connections
I have a referrence to wye-wye connection comment which was written by a former Westinghouse DTDT engineer which states in part:"The use of a wye-wye connections in distribution systems has not been popular because of the inherent risks of neutral instability."
It goes on to say:"The cheif reasons for avaoiding the wye-wye connection includes magnetizing currents, and unbalanced line to neutral loads. The resultant effect from these conditions is a potential for excessive telephone type interference, heating from the third harmonic currents that are present and high peak system voltages due to wave shap distortion. The peak voltages can exceed 150% of the fundamentaal which of course places a serious stress on the normal value of the insulation usually used in transformers. Note that this is a system problem not just a transformer problem and other devices are subject to the same excessive potentials.
A wye-wye transformer can be used in a system that is carefully engineered, The transformer design must include consideration for extra insulation, larger core mass to compensate for additional harmonic heating and near perfect line to neutral load balancing. This protects the transformers but does nothing for the balance of the system components. Distribution systems are not the place for the use of the wye-wye connecton. Onlt the brilliant of the follish should use it."
Bottom line? Dtick with the delta-wye.
I have a referrence to wye-wye connection comment which was written by a former Westinghouse DTDT engineer which states in part:"The use of a wye-wye connections in distribution systems has not been popular because of the inherent risks of neutral instability."
It goes on to say:"The cheif reasons for avaoiding the wye-wye connection includes magnetizing currents, and unbalanced line to neutral loads. The resultant effect from these conditions is a potential for excessive telephone type interference, heating from the third harmonic currents that are present and high peak system voltages due to wave shap distortion. The peak voltages can exceed 150% of the fundamentaal which of course places a serious stress on the normal value of the insulation usually used in transformers. Note that this is a system problem not just a transformer problem and other devices are subject to the same excessive potentials.
A wye-wye transformer can be used in a system that is carefully engineered, The transformer design must include consideration for extra insulation, larger core mass to compensate for additional harmonic heating and near perfect line to neutral load balancing. This protects the transformers but does nothing for the balance of the system components. Distribution systems are not the place for the use of the wye-wye connecton. Onlt the brilliant of the follish should use it."
Bottom line? Dtick with the delta-wye.
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