To provide a freezing prevention device for a pump, manufacturable at low costs by reducing the number of necessary components, without requiring a large mounting space.
This freezing prevention device is used for the pump driven by a brushless DC motor 14 and preventing freezing of water staying in a pump chamber 20a of the pump. The brushless DC motor 14 has a mold frame 28 constituted by molding a stator 26 with stator windings 24 wound therearound, and is arranged to transfer heat of the mold frame 28 to the pump chamber 20a. A drive circuit 16 for driving the brushless DC motor 14 has an inverter circuit 36 comprising a plurality of switching elements and a control circuit 38 outputting a control signal to each of the switching elements of the inverter circuit 36. The control circuit 38 outputs the control signal to the inverter circuit 36 so as to make the inverter circuit 36 energize the arbitrary stator windings 24 to generate heat without rotating a rotor 30, when temperature below a predetermined value is detected by a temperature sensor 42 arranged in the vicinity of the pump chamber 20a.
Masato Tsuda
Tetsuji Nakamura
Katsuyuki Tomita
Next Patent: HORIZONTAL TYPE RUNNING WATER POWER GENERATOR