Abstract: In an air conditioner, an auxiliary circuit configured to prevent a current flow in a power supply wiring in an operation stop period and to determine whether to adapt an outdoor unit to a unit that is able to transition to a standby mode, is provided on the power supply wiring.

Abstract: An indoor unit of an air conditioner includes a relay K2R switched by an indoor control circuit between an on state in which the relay K2R connects signal and power lines and an off state in which the relay K2R disconnects the signal and power lines. An outdoor unit of the air conditioner includes a relay K13R switched by an outdoor control circuit between an on state in which the relay K13R connects the outdoor control circuit to the AC power supply and an off state in which the relay K13R connects the outdoor control circuit to the signal line. The relay K2R is switched to the on state with the relay K13R in the off state. When the outdoor control circuit is started, the relay K13R is switched to the on state, and then the relay K2R is switched to the off state, thereby starting the outdoor unit.

Abstract: A motor driving system including command value output means configured to output an analog value according to a rotation speed command; a first power line having first switching means; a drive circuit, to which power is supplied via the first switching means and the first power line, driving a motor supplying rotation based on the analog value; and switching control means configured to make the first switching means nonconductive when the analog value is smaller than a first predetermined value, and independent of the command value output means.

Abstract: An indoor unit of an air conditioner includes a relay K2R switched by an indoor control circuit between an on state in which the relay K2R connects signal and power lines and an off state in which the relay K2R disconnects the signal and power lines. An outdoor unit of the air conditioner includes a relay K13R switched by an outdoor control circuit between an on state in which the relay K13R connects the outdoor control circuit to the AC power supply and an off state in which the relay K13R connects the outdoor control circuit to the signal line. The relay K2R is switched to the on state with the relay K13R in the off state. When the outdoor control circuit is started, the relay K13R is switched to the on state, and then the relay K2R is switched to the off state, thereby starting the outdoor unit.

Abstract: In an air conditioner, an auxiliary circuit configured to prevent a current flow in a power supply wiring in an operation stop period and to determine whether to adapt an outdoor unit to a unit that is able to transition to a standby mode, is provided on the power supply wiring.

Abstract: A motor driving system including command value output means configured to output an analog value according to a rotation speed command; a first power line having first switching means; a drive circuit, to which power is supplied via the first switching means and the first power line, driving a motor supplying rotation based on the analog value; and switching control means configured to make the first switching means nonconductive when the analog value is smaller than a first predetermined value, and independent of the command value output means.