Mutual Inductance To Blame?
Mutual Inductance To Blame?
(OP)
I have an application where (10) 350mcm cables are arranged on 1" centers in an open wire tray. All 10 cables carry one phase of a three phase delta connected load. The total phase current is 2200A. When I measure the current on the individual conductors I get readings of 150A on the center cables and progressively higher readings towards the outside cables where I measure 350A.
Someone will be quick to first point out that the cable arrangement is not good, I know that. My question is, could (or is) the mutual inductance between the cables in the center causing increased impedence and hence less current as compared to the cables on the outside?
Someone will be quick to first point out that the cable arrangement is not good, I know that. My question is, could (or is) the mutual inductance between the cables in the center causing increased impedence and hence less current as compared to the cables on the outside?






RE: Mutual Inductance To Blame?
RE: Mutual Inductance To Blame?
Would rebundling of the cables into ten 3ø groups solve the imbalance problem?
RE: Mutual Inductance To Blame?
RE: Mutual Inductance To Blame?
Where are the other phases, now? Are they also horizontally arranged as 10-single cores but located below the phase you described?
Busbar's suggestion is a good one. As suggested arrange the three phases as one symmetric bundle. This will eliminate variation of the self inductances, but only if the wire tray is non-magnetic or if the bundle is rolled or transposed along is length. Then, adjacent bundles should be further transposed with respect to one another, to reduce mutual inductance effects. It would also be helpful if the bundles can be arranged vertically, say three horizontally placed bundles, in three tray levels.
Please note, the above is academic if the actual distance is relatively short!
RE: Mutual Inductance To Blame?
Jghrist-I think that the skin effect is dominant in the same cable core,i am not sure this is the case.
RE: Mutual Inductance To Blame?
RE: Mutual Inductance To Blame?