WAP 5, WAP 7 and WAG 9 are called 3 Phase Locomotives of IR which is controlled by various loco softwares. where as WAP 4 WAG 7 are conventional single phase locomotives.
What is 3 Phase electric power?
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Please see the attached PDF Documents to know a to z about 3 Phase Locomotives. Apart from this I...
more... have many blogs posted on 3 Phase Locos you may also refer to those also.
Attached Docs
103 page PDF for 3 Phase Locos
Software Rlease from 2012 onward for 3 Phase Loco