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Title: Variable current speed controller for eddy current motors

Abstract

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

Inventors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
6570518
Application Number:
ON: DE83006862
Assignee:
ERA-08-018421; EDB-83-051177
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; ELECTRIC MOTORS; SPEED REGULATORS; LATHES; DESIGN; CONTROL SYSTEMS; ELECTRIC CURRENTS; MECHANICAL VIBRATIONS; MIRRORS; SURFACE FINISHING; CONTROL EQUIPMENT; CURRENTS; EQUIPMENT; MACHINE TOOLS; MOTORS; TOOLS; 420200* - Engineering- Facilities, Equipment, & Techniques

Citation Formats

Gerth, H L, Bailey, J M, Casstevens, J M, Dixon, J H, Griffith, B O, and Igou, R E. Variable current speed controller for eddy current motors. United States: N. p., 1982. Web.
Gerth, H L, Bailey, J M, Casstevens, J M, Dixon, J H, Griffith, B O, & Igou, R E. Variable current speed controller for eddy current motors. United States.
Gerth, H L, Bailey, J M, Casstevens, J M, Dixon, J H, Griffith, B O, and Igou, R E. Fri . "Variable current speed controller for eddy current motors". United States.
@article{osti_6570518,
title = {Variable current speed controller for eddy current motors},
author = {Gerth, H L and Bailey, J M and Casstevens, J M and Dixon, J H and Griffith, B O and Igou, R E},
abstractNote = {A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1982},
month = {3}
}