Patent EP0696842A1 successfully refreshed from Google Patents.
EP0696842A1
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EP
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Inverter for pumps and a pump unit therewith
Assignee: Ebara Corp
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Filing: 1995-08-09
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Granted: —
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Expires: 2015-08-09
Abstract
Abstract An inverter unit having a simple circuit configuration which provides reliable control over the performance of a fluid handling pump is presented. An application of the inverter unit to a motor-driven peripheral flow type pump is demonstrated. The inverter unit is constructed so that the inverter unit isolates a three-phase commercial alternative power source from the pump driving alternative power source such that the problems, such as a misconnection of phase relationship, in the commercial power source do not affect the performance of the motor. The pump is powered by an internally-generated power produced within the inverter unit. The inverter unit thus includes: a converter section which rectifies the three-phase commercial power and converts the alternating current power to direct current power; and an inverter section which generates pulse signals having specific frequency and voltage values using the direct current power produced in the converter section. The three-phase alternating current thus generated by the inverter unit are applied to the motor, independent of the phases in the commercial three-phase alternative power source, so as to produce optimum performance of the motor in each of the start-up, steady-state and stopping stages. The pump is thus able to perform reliably at its peak efficiency without the problems encountered in the pumps incorporating conventional inverters.
Inventors
- 👤 Masakazu C/O Ebara Research Co. Ltd. Yamamoto
- 👤 Yoshio C/O Ebara Research Co. Ltd. Miyake
- 👤 Koji C/O Ebara Research Co. Ltd. Isemoto
- 👤 Keita C/O Ebara Research Co. Ltd. Uwai
- 👤 Yoshiaki C/O Ebara Research Co. Ltd. Miyazaki
- 👤 Hitoshi C/O Ebara Densan Ltd. Choshitani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:30
CPC Classifications
F; F04; F04D; F04D15/00; F04D15/0066; H; H02; H02H; H02H7/00; H02H7/08; H02H7/0827; H02H7/085; H02P; H02P1/00; H02P1/16; H02P1/26
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
103 words
An inverter unit for use in controlling a fluid handling pump driven by an electric motor comprising: a converter section for rectifying a three-phase commercial alternating power and converting to a direct current power; and an inverter section for generating a three-phase alternating current power having a specific frequency value and a specific voltage value, from said direct current power produced in said converter section; wherein said three-phase alternating current power provides alternating current power of a defined phase relationship to said electric motor in accordance with signals from a controller device, independently of the connecting lines of said three-phase commercial alternating power.
Claim 2
Dependent Claim
86 words
An inverter unit as claimed in claim 1, wherein said inverter unit is further provided with control means for commanding said specific frequency value and said specific voltage value generated by said inverter unit; and soft-start means for controlling said inverter unit so as to provide, within a pre-determined time interval, a gradual increase in the power applied to the electric motor up to said specific frequency and said specific voltage, during a time span required for the electric motor to reach a full running stage.
Claim 3
Dependent Claim
87 words
An inverter unit as claimed in claim 1, wherein said inverter unit is further provided with control means for commanding said specific frequency value and said specific voltage value generated by said inverter unit; and soft-stop means for controlling said inverter unit so as to provide, within a pre-determined time interval, a decrease in the power applied to said electric motor down from said specific frequency value and said specific voltage value, during a time span required for said electric motor to come to a full stop.
Claim 4
Dependent Claim
33 words
An inverter unit as claimed in claims 1 to 3, wherein said inverter unit is provided with overcurrent detection means for reducing an output level of said inverter unit when overcurrent is detected.
Claim 5
Dependent Claim
33 words
An inverter unit as claimed in claim 4, wherein a means is provided to reduce output frequency and voltage values from said inverter unit so as to obtain a pre-determined standard current value.
Claim 6
Dependent Claim
47 words
An inverter unit as claimed in claims 1 to 3, wherein said inverter unit is provided with means for detecting a phase interruption condition, in the primary and the secondary circuits of the inverter unit, and stopping said electric motor when said phase interruption condition is detected.
Claim 7
Dependent Claim
250 words
An inverter unit as claimed in claims 1 to 3, wherein said inverter unit is provided with means for detecting a no-load condition and stopping said electric motor when said no-load condition is detected, wherein preferably said inverter unit is provided with a current detector for stopping an output signal to said fluid handling pump when a measured current value is lower than a pre-determined value of current, wherein preferably said time span includes a period in which said inverter unit outputs constant values of frequency and voltage, and a means is provided for detecting that a value of the current during said time span is lower than a pre-determined value of the current and stopping delivery of said three-phase driving power to said electric motor, wherein preferably said fluid handling pump is provided with a fluid level detector for detecting no-load condition in said fluid handling pump and stopping delivery of output power to said electrical motor, wherein preferably stator winding of said electrical motor is provided with a thermal protector means for detecting a temperature of said stator winding so as to stop delivery of output power to said electrical motor when said temperature exceeds a pre-determined temperature, wherein preferably said inverter unit generates output signals, relating an output frequency value and an output voltage value, which are unilaterally-determined, and wherein said inverter unit preferably generates an output signal relating an output frequency value and an output voltage value in a digital form, not in an analogue form.
Claim 8
Dependent Claim
27 words
A fluid handling pump provided with an inverter unit as claimed in claims 1 to 7, wherein said fluid handling pump is a peripheral flow type pump.
Claim 9
Dependent Claim
77 words
A fluid handling pump provided with an inverter unit as claimed in claims 1 to 7, wherein preferably said fluid handling pump is provided with a hermetically sealed motor having self-lubricating bearings, wherein preferably said inverter unit is disposed on an external surface of said peripheral flow type pump, and wherein preferably said inverter unit is disposed in an area of said fluid handling pump not adversely affected by discharge pressure of said peripheral flow type pump.
Claim 10
Dependent Claim
50 words
An inverter unit for use in controlling a pump driven by an electric motor comprising: a converter section for rectifying an alternating power and converting to a direct current power; and an inverter section for generating an alternating current power having a specific frequency value and a specific voltage value.
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