Sizing of control power transformer fuses for degraded voltage conditions
Sizing of control power transformer fuses for degraded voltage conditions
(OP)
Hello,
Suppose in a plant that the voltage at an MCC is below normal due to a degraded switchyard voltage. Fed from the MCC are various motors which use size 1, 2 and 3 starters. With a degraded MCC voltage, the contactors are expected to draw more current due to a degraded source voltage. For 480/120V control power transformers, how can I verify that the fuse (primary or secondary) is sized such that it can tolerate such a condition? Generically, CPT primary or secondary fuses can be sized according to NEC or vendor recommendations, but may need to be sized larger in such cases. Thanks for your thoughts.
Suppose in a plant that the voltage at an MCC is below normal due to a degraded switchyard voltage. Fed from the MCC are various motors which use size 1, 2 and 3 starters. With a degraded MCC voltage, the contactors are expected to draw more current due to a degraded source voltage. For 480/120V control power transformers, how can I verify that the fuse (primary or secondary) is sized such that it can tolerate such a condition? Generically, CPT primary or secondary fuses can be sized according to NEC or vendor recommendations, but may need to be sized larger in such cases. Thanks for your thoughts.






RE: Sizing of control power transformer fuses for degraded voltage conditions
Bill
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"Why not the best?"
Jimmy Carter
RE: Sizing of control power transformer fuses for degraded voltage conditions