Abstract: Improvements in heat pump systems having indoor and outdoor heat exchangers, at least two compressors, and conduit connections including associated compressor selector and change over valves operable to control the direction of flow of fluid medium through the heat exchangers from the compressors, and to control whether one or more of the compressors will be operating the system and in all cases to connect the operating compressor or compressors in series with the heat exchangers.

Abstract: A single phase induction motor of the capacitor start, capacitor run type, has a rotor and stator of conventional polyphase design and a two phase stator winding comprising a main winding with approximately 70% as many turns as a comparable conventional single phase induction motor and an auxiliary winding in series with the main winding, the auxiliary winding having two branches wound in opposite directions, each branch having substantially the same number of turns as the main winding. One branch of the auxiliary winding is connected in series with a running capacitor and this combination is in turn connected in parallel with the other branch. The series arrangement of the main and auxiliary winding is connected to the supply line and a starting capacitor may be paralleled with the running capacitor during starting for improved starting torque in the conventional capacitor start manner.