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Title:
WATER SHORTAGE DETECTING METHOD IN PUMPING EQUIPMENT AND ITS DEVICE
Document Type and Number:
Japanese Patent JPH0763170
Kind Code:
A
Abstract:

PURPOSE: To facilitate maintenance by dispensing with a level sensor and a cable for the sensor.

CONSTITUTION: In a comparator 15, an actual current value, which is detected by a detector 10, of a pumping motor 2 and the reference current value predetermined in a setting device 13 are compared with each other, and a signal is outputted to a timer 16 when the actual current value of the pumping motor 2 is reduced because of idle running of the pumping pump 1 due to water shortage and the difference between the actual current value and the reference current value reaches the predetermined range. During the duration set in the setting device 14, the timer 16 excites an operation coil 17a when an output of the comparator 15 continues. According to excitation of the coil 17a, a switch 17 is opened and the operation coil 11a is released from excitation, and consequently, the switch 11 is opened and the pumping motor 2 is stopped.


Inventors:
YOSHIDA MASAAKI
Application Number:
JP20976593A
Publication Date:
March 07, 1995
Filing Date:
August 24, 1993
Export Citation:
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Assignee:
NIIGATA ENGINEERING CO LTD
International Classes:
F04B47/06; F04B49/06; (IPC1-7): F04B47/06; F04B49/06
Domestic Patent References:
JPH01138384A1989-05-31
JPH03282000A1991-12-12
JP2092082B
Attorney, Agent or Firm:
Masatake Shiga (2 outside)



 
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