Circuit for switching fixed rotating speed and adjustable rotating speed of outdoor direct-current motor of air-conditioner

The invention discloses a circuit for switching the fixed rotating speed and the adjustable rotating speed of an outdoor direct-current motor of an air-conditioner. The circuit comprises a fixed voltage division circuit and a fixed voltage division breaking circuit, wherein the fixed voltage division circuit comprises a resistor R17, an adjustable resistor ZW1, a capacitor EC6 and a PNP type triode Q1; the fixed voltage division breaking circuit comprises a photocoupler U9; the triode Q1 is connected with a +15V power supply through the resistor R17; an electrolytic capacitor EC5 is connected in parallel between the +15V power supply and a base electrode of the triode Q1; one end of the adjustable resistor ZW1 after being connected in parallel with the capacitor EC6 is connected between the resistor R17 and the triode Q1; the photocoupler U9 is connected with the base electrode of the triode Q1; and the photocoupler U9 is also connected with a rotating speed control circuit of an outdoor direct-current fan motor of an air-conditioning system. The circuit for switching the fixed rotating speed and the adjustable rotating speed of the outdoor direct-current motor of the air-conditioner has the advantages that the speeds of indoor and outdoor fan motors can be randomly adjusted and controlled, a better heating effect is achieved, the operation safety and reliability of the outdoor motor can be improved, and the like.