Control apparatus for variable-speed reversible motor

An apparatus for controlling a variable-speed reversible motor arrangement comprising:

• a variable-speed reversible main motor for driving a load;
• a subsidiary motor for driving a fan, said subsidiary motor being disposed in coaxial relation with the rotor shaft of said main motor and making controlled rotation independently of the rotation of said main motor;
• temperature sensor means for sensing a temperature of said main motor, said sensor means generating a first output signal when the temperature of said main motor exceeds a first predetermined level, a second output signal when the temperature of said main motor exceeds a second predetermined level higher than said first predetermined level and a third output signal when the temperature of said main motor drops to a level lower than said first predetermined level;
• and
• control means electrically connected to said temperature sensor means for energizing said subsidiary motor in response to said first output signal, deenergizing said main motor in response to said second output signal and deenergizing said subsidiary motor in response to said third output signal.