I've got a question trying to sort out what an isolation transformer really does. I'm a grad student working in a physics lab, and I'm trying to get all my instruments (lock-in amplifiers, a temperature controller, helium level monitor and computer) set up without ground loops and without a bunch of electrical noise. I've read some different papers and books and they all seem to differ on what an isolation transformer actually does (some seem to say it is a cure-all for every noise/ground loop problem you could ever have).
My basic understanding is that all an isolation transformer does is disconnect the 'neutral' wire from the ground wire (the utility company has the two lines connected at some point as a safety feature which will cause your circuit breaker to trip if either the hot or neutral wire gets shorted to the case of an instrument). If this is true, I don't see how an isolation transformer does much since any common mode noise between hot and neutral is coupled across the transformer (since the noise will create a changing magnetic flux just like the 60Hz power will). Am I missing something here?
My basic understanding is that all an isolation transformer does is disconnect the 'neutral' wire from the ground wire (the utility company has the two lines connected at some point as a safety feature which will cause your circuit breaker to trip if either the hot or neutral wire gets shorted to the case of an instrument). If this is true, I don't see how an isolation transformer does much since any common mode noise between hot and neutral is coupled across the transformer (since the noise will create a changing magnetic flux just like the 60Hz power will). Am I missing something here?