Motor driving apparatus and refrigeration cycle equipment

A motor driving apparatus to drive a motor having windings whose connection state can be switched, said motor driving apparatus, comprising:

• a connection switching device to switch the connection state;
• a control power supply generating circuit to provide a switching power supply to the connection switching device;
• an inverter to apply an AC voltage of a variable frequency and a variable voltage value to the motor;
• a control device to control the inverter and the connection switching device;
• and
• an electric quantity detector to detect a first electric quantity of the switching power supply, or at least one second electric quantity which varies with the first electric quantity;
• wherein, before a fall of a voltage of the switching power supply below a minimum voltage required for operation of the connection switching device, the motor is stopped.