A compressor assembly having a first compression mechanism operatively coupled
to a first motor and a second compression mechanism operatively coupled to a second
motor. The first compression mechanism compresses the vapor from a low pressure
to an intermediate pressure and the second compression mechanism compresses the
vapor from the intermediate pressure to a discharge pressure. An electrical circuit
supplies electrical current to the first and second motors during operation of
the compressor assembly. The electrical circuit includes means for, during start-up
of the compressor assembly, initiating the supply of electrical current to the
first motor at a first time and initiating the supply of electrical current to
the second motor at a second time wherein the first time precedes the second time
by a time lapse.