On Apr 9, 7:30*am, "William Sommerwerck"
wrote:
Would there be an EMC or cross-coupling *problem due to 3
free-running oscillator SMPS running inside one box, often the
case that 3 would be togrther in close proximity charging 3
phones at the same time.

It's unlikely their transformers would have sufficient stray flux to produce
interference.

If you're worried, position two of them at right angles, and the third
not-in-line with either.

Please learn how to write a short, simple, declarative sentence! Learning
how will give you a great sense of satisfaction.

Mr. Cook's question was stated just fine, we have some grouches here
this Monday morning.

There is a slight chance that the oscillators would try to sync up, it
depends on how close they are in free-running frequency and also on
how much intercoupling there is between the electronics, as well as
any possible flux coupling between the transformers. Really hard to
predict!