Patents Assigned to The General Electric Company Limited
  • Patent number: 4699524
    Abstract: Apparatus for providing supplementary cooling to the thrust bearing of a vertical shaft machine, without requiring an additional exterior pump and motor, has an oil conducting path formed by grooves in the engaging surfaces of an upper and a lower portion of each bearing shoe. The oil conducting path terminates at an opening on either side of the outer periphery of the shoe. A nozzle is mounted in each opening. The nozzle extends upwardly with a horizontally extending nose portion with the nozzle opening in the end. The nose portion is adjacent the outer periphery of the rotating bearing ring which the shoes support. The ring is mounted to the vertical shaft. The shoes and the ring are immersed in an oil bath. Rotation of the shaft and the ring moves the oil adjacent the periphery of the ring. The nozzles are oriented in opposite directions, preferably facing one another.
    Type: Grant
    Filed: February 9, 1987
    Date of Patent: October 13, 1987
    Assignee: Canadian General Electric Company Limited
    Inventor: Duncan T. Bath
  • Patent number: 4657411
    Abstract: A thrust bearing particularly suitable for use with a vertical shaft machine has a rotating ring mounted to the shaft for rotation with the shaft and having a downwardly directed bearing surface. A base ring is positioned around the shaft and fixedly mounted to a machine foundation. A plurality of segmented bearing shoes extend around the shaft and have upwardly directed bearing surfaces for bearing engagement with the bearing surface of the rotating ring. Each shoe is supported from the base ring by a plurality of hydraulic elements which in one form are cylinders fixed to the base ring with pistons extending axially therefrom to engage the respective bearing shoe. Each cylinder is connected to a manifold to provide to each cylinder a hydraulic fluid under pressure. Because the source is common, each cylinder has hydraulic fluid at the same pressure.
    Type: Grant
    Filed: August 25, 1986
    Date of Patent: April 14, 1987
    Assignee: Canadian General Electric Company Limited
    Inventor: Duncan T. Bath
  • Patent number: 4635769
    Abstract: A clutch is interposed between the driving gears of a grinding mill and the driving motor to protect the gears from damage by mechanical overloading. The clutch is set to slip at torques below those required to structurally damage the gears yet higher than design load and the clutch released and the mill is shut down after a preset degree of clutch slippage occurs.
    Type: Grant
    Filed: March 7, 1986
    Date of Patent: January 13, 1987
    Assignee: Canadian General Electric Company Limited
    Inventor: Peter de Hertel Eastcott
  • Patent number: 4636910
    Abstract: A system having a bus protected against overvoltage by a plurality of series connected zinc oxide varistors in a column, uses temperature sensors to protect the varistors from damage. First temperature sensors detect that a safety tripping temperature has been reached and lower the bus voltage. Second temperature sensors detect a thermal runaway temperature has been reached and disconnect the bus. Normal operation is restored when the detected temperature falls below the safety tripping temperature. To protect against very rapidly increasing overvoltages, the current flow is monitored and when it exceeds a threshold a signal representing current is integrated. When the integrated value reaches a first preset level the voltage on the bus is reduced and when it reaches a second preset level the bus is disconnected to permit the varistors to cool.
    Type: Grant
    Filed: April 30, 1985
    Date of Patent: January 13, 1987
    Assignee: Canadian General Electric Company Limited
    Inventor: Philip Chadwick
  • Patent number: 4594880
    Abstract: In the prior art it is known to determine the density of a roll of paper as it is being wound on a paper receiving roll. The determination is made each time the paper receiving roll makes a constant predetermined number of revolutions. Because the diameter of the paper on the paper receiving roll increases, there is an increasing length of paper added between successive determinations. This makes it more difficult to maintain a desired roll density by controlling various factors during winding. In addition, because the paper web is usually fed onto the roll at a constant rate, the time between successive density determinations increases. The system of the invention provides for an adjustment of the predetermined number of revolutions between density determinations. This number is decremented to provide, very approximately, the same time interval between successive determinations.
    Type: Grant
    Filed: December 27, 1984
    Date of Patent: June 17, 1986
    Assignee: Canadian General Electric Company Limited
    Inventors: James C. Murdoch, Clarence J. Klassen
  • Patent number: 4572978
    Abstract: In a commutator formed by a plurality of commutator bars clamped between an annular shell and a clamping ring held together by studs, the life of the commutator may be extended significantly by imposing a resilient damper between the stud and the inside wall of a passage in the shell or ring, or both. The damper is spaced inwardly from the end of the stud, preferably by an amount approximately equal to one third of the length of the stud.
    Type: Grant
    Filed: July 6, 1984
    Date of Patent: February 25, 1986
    Assignee: Canadian General Electric Company Limited
    Inventor: Martin VanDuyn
  • Patent number: 4556830
    Abstract: A speed controller for a mill drive has two control portions. The first control portion has a first speed of response for controlling mill speed during normal operation. The second control portion has a second speed of response, faster than the first speed of response, for controlling mill speed following abrupt changes in load torque. The first control portion has a reference speed input and this is compared with actual motor speed and the result gives a current reference signal. The current reference signal is compared with a signal representing actual current to derive an error signal used to control the supply of power to the motor. The second control portion multiplies the current reference signal with a signal representing flux to provide a signal representing a model of developed torque. This is compared with a signal representing a model of load torque and the difference integrated to provide a signal representing a model of motor speed.
    Type: Grant
    Filed: September 19, 1984
    Date of Patent: December 3, 1985
    Assignee: Canadian General Electric Company Limited
    Inventors: Charles L. Schwalm, Walter A. Hill
  • Patent number: 4556826
    Abstract: In a drive system for a grinding mill the load torque plus frictional torque may increase considerably as a loaded mill is inched from its rest position and will suddenly decrease when the load tumbles or cascades. The applied torque or driving torque must increase at a corresponding rate and should also decrease when the load cascades. If the applied torque exceeds by a significant amount the load torque plus frictional torque, a destructive hammering will occur in the gear train and this will be generally proportional to the excess of applied torque for a synchronous motor drive. The drive system has a DC source which is commutated by a commutating device to provide a low frequency stepped alternating voltage to the stator windings of the synchronous motors of the drive system for inching. The output of the DC source has an alternating current component which varies as the difference between the applied torque and the load torque plus frictional torque.
    Type: Grant
    Filed: August 22, 1984
    Date of Patent: December 3, 1985
    Assignee: Canadian General Electric Company Limited
    Inventors: Ronald C. Trussler, Andrew C. Stevenson, Peter D. Eastcott
  • Patent number: 4538202
    Abstract: A device for protecting the secondary winding of a current transformer against destructive or dangerous overvoltages when connected across the secondary, has a transparent tubular casing with a stud support and conductive stud within one end. The stud is threadably mounted in the stud support so it can be adjusted longitudinally and it has an arcing surface on its inner end. Within the other end a support member carries a longitudinally sliding conductive plunger. The plunger is biased inwardly towards the arcing surface of the stud but it is restrained from inward movement by a fusible element which engages it and restrains it. The fusible element forms another arcing surface spaced a predetermined distance from the arcing surface on the stud. One terminal is provided on the outer end of the conductive stud and another on the outer end of the support member connected to the plunger by a flexible braid. A small overvoltage of short duration causes an arc current to flow to limit the voltage.
    Type: Grant
    Filed: February 23, 1984
    Date of Patent: August 27, 1985
    Assignee: Canadian General Electric Company Limited
    Inventor: Donald K. Ferguson
  • Patent number: 4520910
    Abstract: There is provided a control apparatus for stopping a large grinding mill driven by two synchronous motors coupled to the mill through respective air clutches. The control includes a clutch actuator control which applies a predetermined amount of pressure of predetermined duration to the clutches sufficient to at least partially close the clutches but insufficient to fully close and lock-up the clutches. The control apparatus further includes an enable control which periodically enables the clutch actuator control to apply the predetermined amount of pressure. The enable control enables the clutch actuator control for a predetermined time duration sufficient to stop motion of the mill and synchronous motors. The present invention provides a system for bringing a mill to a stop relatively quickly without adding significant costs to the mill controls.
    Type: Grant
    Filed: December 9, 1982
    Date of Patent: June 4, 1985
    Assignee: Canadian General Electric Company Limited
    Inventors: Peter deHertel Eastcott, Ronald C. Trussler
  • Patent number: 4496883
    Abstract: There is provided an electrical inching control for inching a drive system comprising a grinding mill driven by one or more three phase synchronous motors. The electric inching control includes an inching power bus and contactors or the solid state equivalent thereof. The inching bus supplies energy for the stator windings of the synchronous motors. The contactors or switches connect the positive and negative sides of a direct current power supply to the different phases of the stator windings in a sequence which provides a stepped rotating magnetic field, and the rotor field windings are excited with direct current. The interacting stator and rotor fields causes a rotation of the rotor a predetermined amount with each step causing the mill also to rotate a respective predetermined amount.
    Type: Grant
    Filed: December 1, 1983
    Date of Patent: January 29, 1985
    Assignee: Canadian General Electric Company Limited
    Inventors: Peter D. Eastcott, Ronald C. Trussler
  • Patent number: 4491767
    Abstract: In the inching of a grinding mill or similar apparatus which is driven by a pair of synchronous motors through fluid actuated clutches, the motors must be angularly alined one with the other in order that the load be shared equally between the motors. The apparatus of the invention connects the field supply to both motor fields and then it connects a zero frequency supply (i.e. a DC supply) to the stator windings of both motors and ramps up or increases the amplitude of the supply. This brings the rotors into alinement without undue oscillation. When the amplitude of the low frequency supply reaches a predetermined level, the clutches are closed or locked and the motors are connected to the load with the rotors in angular coincidence or alinement.
    Type: Grant
    Filed: December 19, 1983
    Date of Patent: January 1, 1985
    Assignee: Canadian General Electric Company Limited
    Inventors: Peter D. Eastcott, Ronald C. Trussler
  • Patent number: 4475139
    Abstract: A protective circuit for a plurality of series connected thyristors where each thyristor has in parallel with it a resistance, capacitance type snubber circuit and a metal oxide varistor. The arrangement of the series connected thyristors, snubber circuits and their metal oxide varistors has in parallel with it a main metal oxide varistor. The main varistor is responsive to external transient surges so as to conduct large currents. The outer varistors are selected to have values so as to conduct a much smaller or minimal current relative to the current conducted by the main varistor. In a preferred arrangement, a tuning inductor is in series with the thyristors, snubber circuits and parallel arranged varistors. Also, the main varistor is arranged in parallel with the series connection of thyristor, snubber, varistor combination and inductor, and in series with a bank of capacitors.
    Type: Grant
    Filed: December 30, 1981
    Date of Patent: October 2, 1984
    Assignee: Canadian General Electric Company Limited
    Inventor: Philip Chadwick
  • Patent number: 4451870
    Abstract: A capacitive signal coupler for use with a large dynamoelectric machine for coupling signals indicative of corona discharge from the stator bars to a monitor system is combined with an end cap made to fit over the connector extending between two stator bars. The end cap has a high voltage capacitor encapsulated in its walls. One lead from the capacitor is fastened to the connector with a screw before the end cap is installed. The other lead projects from the end cap and is connected to one terminal of a high voltage fuse. The fuse is secured to the end cap. The other terminal of the fuse is adapted to be connected to a cable leading to a monitor system. The coupler is preferably fastened to the lower end of the conductors of a vertical dynamoelectric machine where there is a full range of choice of location in the circuit voltages from line to neutral in two bar steps. The end cap is epoxy sealed in place to make an installation requiring little more space than the installation of a normal end cap.
    Type: Grant
    Filed: November 22, 1982
    Date of Patent: May 29, 1984
    Assignee: Canadian General Electric Company Limited
    Inventors: Palmer Lonseth, Neil R. Selkirk, Donald G. Moorby
  • Patent number: 4447739
    Abstract: Apparatus for withdrawing the rotor from the stator in a bulb-type generator makes the rotor and the inner portion of the stator accessible for repair or maintenance without having to disassemble the housing and stator. A pair of detachable beams are placed in the housing when the rotor is stationary so they extend through holes provided in the rotor above the shaft on which the rotor turns. The beams are conveniently mounted to the upper stay tower structure at their downstream end, and to the housing at their upstream end. An additional support member may be used between the beams and the bottom of the housing at the upstream end of the beams. Shoes which slidably engage the beam are placed between the beam and the rotor to support the rotor. Preferably the shoes include a hydraulically operated piston which can be extended to ensure positive engagement with the beam. The rotor has an inner ring which is bolted to a driving disc on the shaft.
    Type: Grant
    Filed: April 27, 1982
    Date of Patent: May 8, 1984
    Assignee: Canadian General Electric Company Limited
    Inventors: James H. Ferguson, Murray W. Calderwood
  • Patent number: 4422320
    Abstract: A device for determining the tightness of a wedge used to close the slot of a dynamoelectric machine and firmly restrain the conductors installed in the slot, is in the form of a tapping hammer or similar tapping tool. The heat of the hammer contains an accelerometer which outputs a pulse signal having a duration representing the time the head is in contact with the wedge. The pulse signal duration is also related to the tightness of the wedge. Associated electronic circuitry measures the time duration and displays the measured value on a digital display on the hammer unless this display is inhibited. The strength of each blow is assessed by an integrating circuit which gives an output related to the strength of the blow. If this output is not within predetermined upper and lower limits, defining a "window", the display of the measured time duration is inhibited and instead the display indicates that the blow was too hard or too weak.
    Type: Grant
    Filed: February 1, 1982
    Date of Patent: December 27, 1983
    Assignee: Canadian General Electric Company Limited
    Inventors: Donald G. Moorby, Graham T. McMillen, Ralph S. Flemons
  • Patent number: 4422022
    Abstract: A speed control for a DC motor drive having regenerative braking and a field reversing control, has a field current feedback circuit which includes a modifier to change the feedback signal in accordance with the saturation curve of the field to provide a feedback signal representing field strength or field flux. Because motor field strength is regulated as a function of the required field strength, the control tends to make the speed of response independent of actual field strength. Also, a feedback signal is provided which is a function of the product of actual field strength and desired armature current, i.e., related to torque, and this controls the speed signal so that the gain of the speed regulating amplifier is inversely proportional to field strength. This allows drive operation at reduced field strength while maintaining the response.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: December 20, 1983
    Assignee: Canadian General Electric Company Limited
    Inventors: Walter A. Hill, Andrew C. Stevenson, Peter G. McKenna
  • Patent number: 4420996
    Abstract: A paper slitter machine having a plurality of slitter heads in mutually spaced apart relation located across the width of the machine, each slitter head having a slitter disc operable in cooperating relation with a respective annular disc or slitter band mounted for rotation on a shaft, for the slitting of a paper web into discrete width portions on passage of the web past the slitter heads, is provided with a plurality of slitter indexing means mounted on traverse means for retraction to a position clear of the machine, the slitter indexing means having a slitter stop for each slitter head, the stops being adjustable upon the traverse means to permit pre-indexing of each of the stops to a desired predetermined position along the length of the traverse means such that, with the traverse means repositioned within the slitter machine and having the stops positioned in an operative position, each of the slitter heads may then be brought rapidly into indexed relation with the respective pre-set stop, whereby the
    Type: Grant
    Filed: January 19, 1982
    Date of Patent: December 20, 1983
    Assignee: Canadian General Electric Company Limited
    Inventors: Robert Greding, Rodney H. Bryce
  • Patent number: 4420809
    Abstract: A frequency determining apparatus for receiving an input signal of unknown frequency and providing an output signal representing the frequency where the output signal is updated at substantially regular intervals regardless of the frequency of the input signal. A frequency divider or prescaler divides the input signal by a factor n to give an adjusted signal. A gated counter counts stable clock pulses for a time period related to the period of the adjusted signal to give a count inversely related to the frequency of the adjusted signal. A calculator corrects the count for the factor n and derives an output signal representing the frequency of the input signal. The calculator also determines if the count has increased above an upper limit or decreased below a lower limit, and if so it changes the factor n accordingly to maintain the count and correspondingly the adjusted signal within a predetermined range.
    Type: Grant
    Filed: May 27, 1981
    Date of Patent: December 13, 1983
    Assignee: Canadian General Electric Company Limited
    Inventor: Gordon F. Pierce
  • Patent number: 4392121
    Abstract: A receiver for an a.c. electrical supply signalling arrangement of the kind in which information is transmitted by impressing on the supply voltage waveform voltage reductions which bridge the zero crossings in the waveform wherein detection by the receiver of an impressed voltage reduction is achieved by comparing the integral of the supply voltage over a period immediately preceding a voltage zero crossing when a voltage reduction is present with a corresponding integral obtained when no voltage reduction is present.
    Type: Grant
    Filed: December 2, 1980
    Date of Patent: July 5, 1983
    Assignee: The General Electric Company Limited
    Inventors: Frederick M. Gray, Charles G. Leedham