GB1338644A - Speed controls for electric motors - Google Patents

Speed controls for electric motors

Info

Publication number
GB1338644A
GB1338644A GB325171A GB1338644DA GB1338644A GB 1338644 A GB1338644 A GB 1338644A GB 325171 A GB325171 A GB 325171A GB 1338644D A GB1338644D A GB 1338644DA GB 1338644 A GB1338644 A GB 1338644A
Authority
GB
United Kingdom
Prior art keywords
motor
speed
current
voltage
frequency
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.)
Expired
Application number
GB325171A
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.)
Scragg & Sons
Original Assignee
Scragg & Sons
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 Scragg & Sons filed Critical Scragg & Sons
Publication of GB1338644A publication Critical patent/GB1338644A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
    • H02P23/28—Controlling the motor by varying the switching frequency of switches connected to a DC supply and the motor phases
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/047—V/F converter, wherein the voltage is controlled proportionally with the frequency

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)
  • Control Of Multiple Motors (AREA)

Abstract

1338644 Control of A.C. motors; inverting ERNEST SCRAGG & SONS Ltd 20 Jan 1972 [27 Jan 1971] 3251/71 Headings H2J and H2F A squirrel-cage motor 6 is controlled to maintain constant any selected speed within a wide range under a variable motor load and good torque regulation is obtained by maintaining the slip as a constant fraction of motor speed. Feedback signals of voltage and current supplied to the motor 6 are employed by the control system such that voltage feedback predominates in regulating motor torque at high motor speeds and current feedback predominates in regulating motor torque at low motor speeds. A speed demand signal 1 controls the frequency of an oscillator 2 which drives a three-stage ring counter 3. The six pulsed outputs, staggered by 60 degrees, pass into a waveform generator 4 which gates pairs of outputs together to synthesize six 120 degrees on and 60 degrees off pulse train waveforms to drive a three-phase inverter 5 powering the motor 6. Three mixing gates 7 modulate the waveforms and the input to gates 7 is derived from a control amplifier 8 in series with a pulse width modulated, high frequency oscillator 9, the amplifier 8 controlling the mark space ratio of oscillator 9. The amplifier 8 has three inputs, of which two are motor voltage and motor current, passed through dividers 10, 11, to render them as low voltage signals for the control circuit, and the third input is a signal derived from the speed demand signal 1 and modified in a device 12 according to the low I D =k(Kx), where I D = demand current, x= frequency (motor speed), and K is a constant. This ensures that the gain of the current feedback loop decreases with increasing frequency. The full inverter and control systems are set out in Figs. 2, 3A, 3B, 3C and 3D (not shown).
GB325171A 1971-01-27 1971-01-27 Speed controls for electric motors Expired GB1338644A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB325171 1971-01-27

Publications (1)

Publication Number Publication Date
GB1338644A true GB1338644A (en) 1973-11-28

Family

ID=9754812

Family Applications (1)

Application Number Title Priority Date Filing Date
GB325171A Expired GB1338644A (en) 1971-01-27 1971-01-27 Speed controls for electric motors

Country Status (9)

Country Link
JP (1) JPS5047125A (en)
CA (1) CA934001A (en)
CH (1) CH551105A (en)
DE (1) DE2203487B2 (en)
FR (1) FR2124731A5 (en)
GB (1) GB1338644A (en)
IL (1) IL38533A (en)
IT (1) IT946880B (en)
NL (1) NL7201137A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2425413A (en) * 2005-04-23 2006-10-25 Johnson Electric Sa Drive circuit for a hair clipper achieving constant speed
US7446495B2 (en) 2005-03-18 2008-11-04 Johnson Electric S.A. Drive circuit for a hair clipper

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2743605C2 (en) * 1977-09-28 1982-03-25 URANIT, Uran-Isotopentrennungs-Gesellschaft mbH, 5170 Jülich Method and circuit arrangement for determining the work of reversal of magnetization of the rotor of a hysteresis motor
ATE22511T1 (en) * 1982-08-31 1986-10-15 Telemecanique Electrique METHOD AND DEVICE FOR MEASURING THE SLIP OF AN ENGINE.
FR2546683B1 (en) * 1983-05-24 1985-07-26 Telemecanique Electrique METHOD FOR REGULATING THE POWER SUPPLY OF ELECTRIC MOTORS AND DEVICE FOR IMPLEMENTING THE METHOD

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7446495B2 (en) 2005-03-18 2008-11-04 Johnson Electric S.A. Drive circuit for a hair clipper
GB2425413A (en) * 2005-04-23 2006-10-25 Johnson Electric Sa Drive circuit for a hair clipper achieving constant speed

Also Published As

Publication number Publication date
JPS5047125A (en) 1975-04-26
CH551105A (en) 1974-06-28
IT946880B (en) 1973-05-21
FR2124731A5 (en) 1972-09-22
CA934001A (en) 1973-09-18
NL7201137A (en) 1972-07-31
IL38533A0 (en) 1972-03-28
AU3774272A (en) 1973-07-12
IL38533A (en) 1974-11-29
DE2203487A1 (en) 1972-12-21
DE2203487B2 (en) 1977-04-14

Similar Documents

Publication Publication Date Title
US4333042A (en) System for driving a motor by a pulse width modulation inverter
GB1362849A (en) Static power conversion ciruit
GB1324339A (en) Direct current control circuit
GB1187709A (en) Improvements in or relating to Slip Frequency Control of an Asynchronous Electrical Machine
US3781615A (en) System for phase shifting inverters to obtain a variable modulated waveform
GB1419197A (en) A-c adjustable speed motor drive system
GB1346156A (en) Power supply system
GB1449177A (en) Servo system and an ac motor controlled thereby
GB1504771A (en) Speed control systems
ES402039A1 (en) Digital slip frequency control circuit for asynchronous dynamo electric machines
GB1487976A (en) Paralleling control for phase synchronized generators
GB1338644A (en) Speed controls for electric motors
GB1301094A (en) Servo system
GB1110584A (en) Improvements in electric motor control circuits
GB1064591A (en) Variable frequency power supplies
US3638088A (en) A device for generating a variable low-frequency ac current using pulse sampling techniques
GB1043225A (en) Improvements in or relating to speed control systems for electric motors
GB1129420A (en) Improvements in or relating to frequency stabilizers
US3978383A (en) Speed controls for electric motors
GB1102316A (en) Circuit arrangements for controlling the speed of commutator or induction motors
SU1083316A1 (en) Variable-frequency asynchronous electric drive
GB1232018A (en)
GB1162229A (en) Speed Control Apparatus
SU752721A1 (en) Apparatus for double-zone control of induction electric motor
GB1150719A (en) Arrangements for Controlling the Speed of Asynchronous Electrical Machines

Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee