Circulating currents in ~100 words.
What are circulating currents, why are random-wound windings called random, why should you care? Find out here, with convenient bullet points!
- In a stranded winding, the total current gets unevenly divided between parallel strands.
- This increases losses. A lot, more often than not.
- The losses vary randomly motor-to-motor. This is because the strands shift their relative positions between slots, randomly.
- Regarding this switching, the following seem to hold true:
- The positions in one slot depend on the position in the previous slot.
- Strands move in bundles: those close to each other in one slot, are probably close to each other in the next one too.
- Ignoring either assumption leads to an unrealistically narrow distribution of total losses.
For further reference, here’s my poster from the PEMD conference this (2018) Spring.
An Improved Sampling Algorithm for Stochastic Modelling of Random-Wound Electrical Machines from Antti Lehikoinen