No phase shift in the transformer itself...The secondary is in phase with the primary, depending of course on how you hook up the secondary. But if there is enough noise on the primary to get through those big filter caps (doubtful), the phase of the noise wouldn't really matter. I'm pretty sure that it will be filtered out by the main filter caps and the small bypass caps that I'm sure you'll put on the bridge rectifier. The only other issue would be RF noise generated by the motor itself, but unless it is a crappy motor that should not be a problem either. Besides, the motor is mounted outside the amplifier chassis, which will shield it from RF noise.
The diagram below was pulled from an article on transformers that I googled up... http://www.allaboutcircuits.com/vol_2/chpt_9/4.html
The dots on the schematic denote the polarity of the windings. This article says that manufacturers have come up with a "dot convention" to indicate polarity...If there aren't any dots on the transformer a dual trace scope will immediately show you which is which.
The diagram below was pulled from an article on transformers that I googled up... http://www.allaboutcircuits.com/vol_2/chpt_9/4.html
The dots on the schematic denote the polarity of the windings. This article says that manufacturers have come up with a "dot convention" to indicate polarity...If there aren't any dots on the transformer a dual trace scope will immediately show you which is which.