Generator start up system for transport refrigeration system

An all electric transport refrigeration system receives its compressor electric drive motor power and all other electrical power from a single on-board engine driven permanent magnet generator (300). A dual winding three phase electric motor (118) powers the compressor. The respective sets of windings (10, 20) of the motor (118) are energised in a predetermined sequence during start up. This results in a system that can use a smaller generator while at the same time achieves the start up torque necessary to operate the compressor (116).