GB2294827A - Motor control unit with current interrupter and overload relay - Google Patents

Motor control unit with current interrupter and overload relay Download PDF

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Publication number
GB2294827A
GB2294827A GB9422106A GB9422106A GB2294827A GB 2294827 A GB2294827 A GB 2294827A GB 9422106 A GB9422106 A GB 9422106A GB 9422106 A GB9422106 A GB 9422106A GB 2294827 A GB2294827 A GB 2294827A
Authority
GB
United Kingdom
Prior art keywords
control unit
motor control
circuit
overload relay
interrupter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9422106A
Other versions
GB2294827B (en
GB9422106D0 (en
Inventor
Indrajit Purkayastha
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to GB9422106A priority Critical patent/GB2294827B/en
Publication of GB9422106D0 publication Critical patent/GB9422106D0/en
Publication of GB2294827A publication Critical patent/GB2294827A/en
Application granted granted Critical
Publication of GB2294827B publication Critical patent/GB2294827B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
    • H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0038—Details of emergency protective circuit arrangements concerning the connection of the detecting means, e.g. for reducing their number

Landscapes

  • Protection Of Generators And Motors (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

A motor control unit 1 utilizes a single current sensor 3 for both an overload relay 4 and a circuit interrupter 2. The motor control unit includes a rating plug 3 that is configured to determine the occurrence of an overcurrent condition and correspondingly signals the overload relay 4 or circuit interrupter 2 depending on the nature of the overcurrent condition. A large instantaneous overcurrent causes the interrupter 2 to open. A smaller overcurrent lasting a finite time actuates relay 4 and contacts 6. <IMAGE>

Description

MOTOR CONTROL UNIT WITH CURRENT ZNTRRPTR AND OVERWAD Y A new motor control unit 1 with a first current interrupter 2 and an overload relay 4 controlled by a single, shared current sensor, a rating plug 3, has been developed, as shown in Figure 1. Typical motor control unite use two current sensors, one for the current interrupter and the other for the overload relay.
A motor control unit 1 regulates and distributes three phase electric power from a power source 7 to a motor 8.
Initially the electric power flows through the first current interrupter 3 that consists of three circuit breaker. Each phase of electric power flows through a separate circuit breaker in the first current interrupter 2. Then the electric power passes through the second current interrupter 6 of the motor control unit 1.
The second current interrupter 6 consists of three contactore which are controlled by the overload relay 4.
Each phase of electric power flows through a separate contactor in the second current interrupter 6. After passing through the second current interrupter 6, the electric power is fed to the motor 8.
The motor control unit 1 also includes a single rating plug 3 in the first current interrupter 2 that separately monitors the electric current amplitude of each phase flowing the three circuit breakers. A general description of a rating plug and current amplitude monitoring is found in U.S. Pat. Nos. 4,658,323 and 5,204,798.
The first current interrupter 2 opens the electric circuit between the power source 7 and the motor 8 when a large instantaneous overcurrent is detected by the rating plug 3. The second current interrupter 6 opens the same electric circuit when a smaller overcurrent, lasting a finite period of time, is deteated by the rating plug 3.
If the rating plug 3 detects a current through one of circuit breaker with an amplitude that exceeds a first level for a finite period of time, a signal is transmitted to and actuates the overload relay 4. The actuated overload relay 4 then signals the contactor of the second current interrupter 6 through which the same overcurent flows so as to open that that contractor. As a result the electric circuit between the power source 7 and the motor 8 is also opened.
The overload relay 4 is powered by the same electric power that powere the motor 8. The electric power's voltage is stepped down by the control power transformer 5 before being fed to the overload relay 4.
If the rating plug 3 detects in a circuit breaker an instantaneous current level with an amplitude that exceeds a second level, larger than the first level, a signal is transmitted to that circuit breaker 3. The signal causes the circuit breaker to separate its contacts. As a result, the electric circuit between the power source 7 and the motor 8 is opened.

Claims (7)

1. A motor control unit comprising: a current transformer arranged for connection within an electrical distribution circuit; a rating plug connecting with said current transformer for determining the occurrence of an overcurrent condition within an electrical distribution circuit: a first circuit interrupter connecting with said rating plug and interrupting circuit cun-ent upon occurrence of an overcurrent condition of a first predetermined magnitude: and an overload relay connecting with said rating plug for interrupting circuit current upon occurrence of an overcurrent condition of a second predetennined magnitude.
2 The motor control unit of claim 1 including a second circuit interrupter cotiiecting with said overload relay and responding to said overload relay for interrupting circuit current.
3. T The motor control unit of claim 1 wherein said first circuit interrupter comprises a plurality of circuit breakers. one circuit being connected within a corresponding phase within an electrical distribution system.
4. The motor control unit of claim 1 wherein said second circuit interrupter comprises a plurality of motor contactors. one motor contactor being connected within a corresponding please within an electrical distributioji system.
The motor control unit of claim 2 wherein said first circuit interrupter and said second circuit interrupter are electrically-connected in series.
6. The motor control unit of claim 1 wherein said first predetermined magnitude comprises an instantaneous overcurrent.
7. The motor control unit of claim l wherein said second predetennined magnitude comprises less than an instantaneous overcurrent.
GB9422106A 1994-11-02 1994-11-02 Motor control unit with current interrupter and overload relay Expired - Fee Related GB2294827B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9422106A GB2294827B (en) 1994-11-02 1994-11-02 Motor control unit with current interrupter and overload relay

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9422106A GB2294827B (en) 1994-11-02 1994-11-02 Motor control unit with current interrupter and overload relay

Publications (3)

Publication Number Publication Date
GB9422106D0 GB9422106D0 (en) 1994-12-21
GB2294827A true GB2294827A (en) 1996-05-08
GB2294827B GB2294827B (en) 1999-04-14

Family

ID=10763784

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9422106A Expired - Fee Related GB2294827B (en) 1994-11-02 1994-11-02 Motor control unit with current interrupter and overload relay

Country Status (1)

Country Link
GB (1) GB2294827B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0999631A1 (en) * 1998-11-06 2000-05-10 Abb Research Ltd. Device for the protection of an electric motor and related method
WO2020169753A1 (en) * 2019-02-22 2020-08-27 Future Systems Besitz Gmbh Method and apparatus for protecting an electrical load

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4243920A (en) * 1977-09-20 1981-01-06 Emil Brehm Control device for monitoring machines driving revolving devices and method for operating the device
GB2110447A (en) * 1981-11-20 1983-06-15 Nitto Kohki Co Drilling machines having an electromagnetic base
US5204798A (en) * 1991-07-22 1993-04-20 General Electric Company Metering accessory for molded case circuit breakers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4243920A (en) * 1977-09-20 1981-01-06 Emil Brehm Control device for monitoring machines driving revolving devices and method for operating the device
GB2110447A (en) * 1981-11-20 1983-06-15 Nitto Kohki Co Drilling machines having an electromagnetic base
US5204798A (en) * 1991-07-22 1993-04-20 General Electric Company Metering accessory for molded case circuit breakers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0999631A1 (en) * 1998-11-06 2000-05-10 Abb Research Ltd. Device for the protection of an electric motor and related method
WO2020169753A1 (en) * 2019-02-22 2020-08-27 Future Systems Besitz Gmbh Method and apparatus for protecting an electrical load
US12009765B2 (en) 2019-02-22 2024-06-11 Future Systems Besitz Gmbh Method and apparatus for protecting an electrical load

Also Published As

Publication number Publication date
GB2294827B (en) 1999-04-14
GB9422106D0 (en) 1994-12-21

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20081102