Spring return motors for two-position back draft, outdoor air changeover, zone, or minimum position damper control. Operate outdoor air dampers for combustion or makeup air in residential and light industrial applications. Operate changeover dampers for heating and cooling systems. Operate minimum position dampers for ventilation and similar applications. Include internal spdt switch for controlling auxiliary equipment, additional motors, or to provide a burner interlock switch. Spring returns motor to start position on power failure. Drive shafts located on both sides of motor. Adjustable auxiliary switch for cascading motors or operating auxiliary equipment. Thermal breaker for overload protection during lifting stroke or if motor stalls.