Brian Whatcott wrote in
:

I don't think so - they are integrated induction motors and
compressors in a can. There's a capacitor that splits the phase, but
they slip the rotating field depending on load - if I recall

B

The capacitor lags the phase so you don't have to spin start them by
hand....they do run at the power line frequency....minus a little phase
slippage caused by the load.

Listen to one that has just started up and note its musical note. Notice
how the note hardly varies as the head pressure comes up to maximum, and
only the running current increases to maintain it.

Invented by Nikola Tesla, Father of Modern Electricity.

(I'm a fanboi...(c

If it had DC motors in it, those compressors would run like your universal
series wound vacuum cleaner or a drill/saw motor....varying widely in speed
as the load doubles/triples from idle.

The smooth steady hum of a compressor reeks of an AC induction motor,
capacitor start/capacitor run.