SE9003591L - Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current - Google Patents

Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current

Info

Publication number
SE9003591L
SE9003591L SE9003591A SE9003591A SE9003591L SE 9003591 L SE9003591 L SE 9003591L SE 9003591 A SE9003591 A SE 9003591A SE 9003591 A SE9003591 A SE 9003591A SE 9003591 L SE9003591 L SE 9003591L
Authority
SE
Sweden
Prior art keywords
value
current
tongs
last
average value
Prior art date
Application number
SE9003591A
Other languages
Swedish (sv)
Other versions
SE9003591D0 (en
Inventor
U Bengtzelius
Original Assignee
Flygt Ab Itt
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 Flygt Ab Itt filed Critical Flygt Ab Itt
Priority to SE9003591A priority Critical patent/SE9003591L/en
Publication of SE9003591D0 publication Critical patent/SE9003591D0/en
Publication of SE9003591L publication Critical patent/SE9003591L/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Protection Of Generators And Motors (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

A tongs transformer is connected to one of the three phases of the motor and the actual root-mean-square value is calculated. This corresponds to a DC level proportional to the current in the motor phase conductor. The limit frequency fc = 1/(17 ms), i.e. the last 17 ms are the basis for the rms value. Then, an average value for the current strength, the rms value, is calculated, which is based on the rms signals during the last 44 seconds, and the difference between the rms value and the average value is calculated. The difference is divided by the average value. The result is a normalised signal which only depends on the relative variations of the original signal. An rms value for the relative variations is calculated with the limit frequency fc = 1/(44s) i.e. the last 44 seconds are the basis of the calculation. The obtained value indicates the current variations around the average value during the last 44 seconds, declared as a percentage of the average value.
SE9003591A 1990-11-12 1990-11-12 Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current SE9003591L (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SE9003591A SE9003591L (en) 1990-11-12 1990-11-12 Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9003591A SE9003591L (en) 1990-11-12 1990-11-12 Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current

Publications (2)

Publication Number Publication Date
SE9003591D0 SE9003591D0 (en) 1990-11-12
SE9003591L true SE9003591L (en) 1992-05-13

Family

ID=20380876

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9003591A SE9003591L (en) 1990-11-12 1990-11-12 Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current

Country Status (1)

Country Link
SE (1) SE9003591L (en)

Also Published As

Publication number Publication date
SE9003591D0 (en) 1990-11-12

Similar Documents

Publication Publication Date Title
EP0792483A4 (en)
CA2071033A1 (en) Method and apparatus for controlling the output voltage of an ac electrical system
GB9814793D0 (en) Power meter for ac electrical systems
RU2548656C1 (en) Method of balancing of phase currents of three-phase four-wire line and device for its implementation
JPS6450718A (en) Method and circuit for controlling operation of parallel electric source and electric systems
EP0105235A3 (en) Electronic ac induction motor brake
JPS6472080A (en) Method and apparatus for testing rectifier of brushless ac dynamotor
SE9003591L (en) Load variations calculator for electric motor - analyses electrical current or effect usage, using tongs transformer connected to one motor phase for measuring current
EP0743528A3 (en) Mains voltage measuring appliance for track vehicles
JPS5442712A (en) Electric car controlling system
SU943613A1 (en) Device for measuring eddy current time constant
SU1112313A1 (en) Device for measuring temperature of winding of ac electrical machine under load
SU789844A1 (en) Active power to d.c. voltage measuring converter
RU2018143C1 (en) Ac power meter
SU1161887A2 (en) Device for measuring active power of single-phase alternating current
ES8407236A1 (en) Method and apparatus for improving the dielectric strength of direct current cable insulation
SE9801582D0 (en) Method and device in an electrical system
JPS58124971A (en) Measuring device of efficiency
JPS6431064A (en) Apparatus for measuring electric parts
JPS57129193A (en) Current detector for dc electric machine
JPS6277065A (en) Measuring method for output voltage of inverter
DE3871187D1 (en) METHOD AND CIRCUIT ARRANGEMENT FOR DECOUPLED CONTROL OF THE COMPONENTS OF A CURRENT VECTOR.
JPS6488166A (en) Detecting method for poor electric insulation part
JPS57142164A (en) Fault detector for secondary circuit in wound-rotor type induction motor
JPS56101562A (en) Insulation resistance measuring method and device thereof of dc electric circuit in use

Legal Events

Date Code Title Description
NAV Patent application has lapsed

Ref document number: 9003591-6