Here's my situation: we've got a 220VAC centrifugal switch motor (draws about 2 amps, maybe less, when running) which is currently switched with a double pole relay. In the USA, it's split phase power with 110VAC on each leg, and we have to switch both legs so there's no voltage in the motor when it's not running.
One of our overseas customers wants us to rewire things such that we only switch one leg, because the other wire for them is a neutral and they say that maintaining the neutral connection prevents noise issues from the motor starting and stopping (issues which we think we've recently addressed with a choice of either SSRs or snubbers.)
I've tried some tests and can't find any improvement in motor related electrical noise by keeping the neutral unswitched, but our customer is quite adamant that it is standard practice and will resolve the noise issues.
Just to be clear, I'm talking about the neutral, not the ground. In either case we'll have a solid ground connection at all times. Is there any reason to think leaving the neutral connected would improve performance? I just don't see it.
Even aside from this particular situation, is there a general rule for this? I know that neutrals don't need to be switched, but I never thought any harm could come from switching them.
One of our overseas customers wants us to rewire things such that we only switch one leg, because the other wire for them is a neutral and they say that maintaining the neutral connection prevents noise issues from the motor starting and stopping (issues which we think we've recently addressed with a choice of either SSRs or snubbers.)
I've tried some tests and can't find any improvement in motor related electrical noise by keeping the neutral unswitched, but our customer is quite adamant that it is standard practice and will resolve the noise issues.
Just to be clear, I'm talking about the neutral, not the ground. In either case we'll have a solid ground connection at all times. Is there any reason to think leaving the neutral connected would improve performance? I just don't see it.
Even aside from this particular situation, is there a general rule for this? I know that neutrals don't need to be switched, but I never thought any harm could come from switching them.