Water supply

• US 20030174450A1
• Filed: 05/19/2003
• Published: 09/18/2003
• Est. Priority Date: 07/07/2000
• Status: Active Grant

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kajiwara, Kenichi, Kishi, Masahiko, Higaki, Nobuhiro, Nakajima, Kaoru, Murai, Yukio, Kawai, Masahito
• Granted Patent: US 6,922,348 B2
• Time in Patent Office: Days
• US Class Current: 361/31
• CPC Class Codes: F04B 17/006 Solar operated
• CPC Class Codes: F04B 47/06 having motor-pump units situated at great depth
• CPC Class Codes: F04D 13/068 Battery powered
• CPC Class Codes: F04D 15/0236 Lack of liquid level being detected by analysing the parameters of the electric drive, e.g. current or power consumption
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

According to the present invention, in a water supply apparatus which converts output power of a solar cell with an inverter to drive a motor pump for pumping up water, a DC brushless motor having no sensor for detecting a position of a rotatable shaft is used as a motor for driving the pump. Further, the water supply apparatus having a pump and a frequency converter for supplying electric power to the pump and controlling a rotational speed of the pump comprises a standard current value table in which rotational frequencies of the pump and standard current values as criteria for shutoff operation at the rotational frequencies are associated with each other, rotational frequency detecting means for detecting a rotational frequency of the pump, standard current value acquiring means for acquiring a standard current value corresponding to the rotational frequency detected by the rotational frequency detecting means with reference to the standard current value table, current detecting means for detecting a current value supplied to the pump, and comparing means for comparing the current value detected by the current detecting means with the standard current value acquired by the standard current value acquiring means.

Claims

1. A water supply apparatus which converts output power of a solar cell with an inverter to drive a motor pump for pumping up water, said water supply apparatus characterized in that a DC brushless motor having no sensor for detecting a position of a rotatable shaft is used as a motor for driving said pump.

2. A water supply apparatus according to claim 1, wherein said inverter has means for automatically setting an operating parameter for operation without said sensor, and means for automatically setting said operating parameter before operation of said pump.

3. A water supply apparatus according to claim 1, wherein said inverter has means for detecting racing operation of said pump based on setting current values for each of operating frequencies.

4. A water supply apparatus characterized by comprising:

a solar cell;

an inverter for converting a direct-current output of said solar cell to an alternating-current output;

a pump driven in response to an output of said inverter by a DC brushless motor having no sensor;

a water storage tank for temporarily storing water which is pumped up by said pump; and

a controller for controlling operation of said pump.

5. A water supply apparatus according to claim 4, wherein said inverter and said controller are disposed on the ground, said motor and said pump are disposed within a well, and said inverter and said pump are connected to each other only by cable wiring for supplying electric power to said pump.

6. A water supply apparatus having a pump and a frequency converter for supplying electric power to said pump and controlling a rotational speed of said pump, said water supply apparatus characterized by comprising:

a standard current value table in which rotational frequencies of said pump and standard current values as criteria for shutoff operation at said rotational frequencies are associated with each other;

rotational frequency detecting means for detecting a rotational frequency of said pump;

standard current value acquiring means for acquiring a standard current value corresponding to the rotational frequency detected by said rotational frequency detecting means with reference to said standard current value table;

current detecting means for detecting a current value supplied to said pump; and

comparing means for comparing the current value detected by said current detecting means with the standard current value acquired by said standard current value acquiring means.

7. A water supply apparatus according to claim 6, wherein said pump is stopped when it is judged that the current value detected by said current detecting means is lower than said standard current value.

8. A water supply apparatus according to claim 6, wherein said pump is stopped after a certain period of time elapses when it is judged that the current value detected by said current detecting means is lower than said standard current value.

9. A water supply apparatus according to claim 7, wherein said pump is restarted after a certain period of time elapses since said pump has been stopped.

10. A water supply apparatus according to claim 8, wherein said certain period of time is predetermined for each rotational frequency of said pump.