Showing papers on "Dynamic braking published in 1969"

Brake system for electrically operated vehicles

Abstract: A braking and driving system for electrically operated vehicles including an electric motor for driving the vehicle which may be operated as a generator to provide additional braking and recovery of braking energy by charging the battery. Hydraulic braking on the drive axle is delayed until the maximum level of electromotive braking is reached. This allows the design distribution of braking between the front and rear axles to be maintained while insuring a maximum recovery of braking energy through charging of the battery.

System for blending dynamic and regenerative braking

Abstract: A method and a system wherein the electric power generated by a motor in the braking mode is distributed between a dynamic brake resistor and the motor supply lines in a ratio that varies as a function of the degree of power receptivity of the motor supply lines. Power receptivity is the capability of the supply lines to accept the power generated by the motor in the braking mode at a given time.

Dc motor reversing system including protective features responsive to reversing selector and to dynamic breaking current

Abstract: A braking and reversing system for a DC motor is disclosed wherein a series controlled switching device and a multiposition selection switch are connected between the motor and the power supply. To effect reversal of the motor, the selection switch is placed in a reverse position which prevents the power supply from providing an output, the series controlled switching device to be turned off and a brake controlled switching device to be turned on. The activation of the brake device inserts a dynamic braking circuit in series with the motor and also prevents the power supply from supplying an output and prevents the controlled switching device from turning on regardless of the setting of the mechanical switch.

Dynamic braking system for electric drive

Abstract: A system for dynamically braking an electrically driven vehicle wherein a retarding means is directly coupled to the engine/generator drive and employed to absorb the major portion of the energy produced during power regeneration. Running at near rated engine speed, the retarding means generates substantially constant braking torque during vehicle deceleration and associated control systems automatically operate the retarding means in response to command signals and employ circuits to maintain the excitation of generator below that of the wheel motors during retarding whereby better power transfer is effected.

Dynamic braking of induction motors

Abstract: The disclosure of this specification relates to a system for braking an induction motor comprising normally nonconducting switch means operable, when conducting, to connect capacitance means to the primary winding of the motor to effect braking of the motor and means responsive to the interruption of the supply to the motor to render the normally nonconducting switch means conducting for a period of time sufficient to bring the motor to rest.

Dynamic braking system

Abstract: There is disclosed an arrangement for controlling dynamic braking of a vehicle traction motor system wherein the effective average dynamic braking resistance is adjustable between predetermined minimum and maximum values, and wherein the motor field system is operated in full field mode or partial field mode, depending on whether commanded (requested) braking current at a given speed is greater or less than a predetermined value which for the given speed is at least that which would obtain in the full field mode and with the maximum effective average dynamic braking resistance in the circuit.

Brake system for electrical motors

Abstract: In a capacitor start motor, a centrifugal actuator, acting upon a balanced but floating plate serves a double function of startwinding switch actuator and mechanical brake. A switching arrangement provides smooth dynamic braking until the mechanical brake is actuated.

Electric drive and brake arrangement and method

Abstract: An electric drive and dynamic braking arrangement intended in a preferred embodiment for driving and braking a vehicle, such as a heavy off-road truck, and having a pair of traction motors arranged to be driven by DC current obtained by rectifying the output of an AC generator, so as to drive the vehicle. Braking is also provided by the traction motors by separately exciting their fields with the generator output and dissipating the current generated in the traction motor armatures in resistance grids connected in series with the armatures. Rapid changeover from the power mode to the brake mode is provided by an arrangement which momentarily short-circuits the generator at the beginning of the brake mode connection to quickly reduce the residual generator voltage to a value sufficiently low to avoid overexciting the traction motors so as to prevent consequent possible damage to them.

Track braking system

Abstract: 1,159,701. Undercarriages. UNDERGROUND MINING MACHINERY Ltd. 6 March, 1967 [16 March, 1966], No. 11425/66. Heading B7L. [Also in Divisions B8 and F2] In a rail-borne vehicle braking system which has vehicle supporting wheels 11, Fig. 1, and at least one separate guide wheel 20 disposed between a rail 10 and a surface 15 which is movable to trap the guide wheel between the rail and itself to apply a braking force, the frictional force developed between the movable surface and the guide wheel is less than the frictional force developed between the guide wheel and the rail. The bogie frame 12 indirectly support pivotably mounted brackets 16 which carry vertically disposed shafts 18 mounting wheels 20. When hydraulic cylinders 22 is pressurized the upper edge of brake plate 15 is drawn inwardly against springs 21 so that wheels 20 are free to rotate. Hydraulic cylinders 22 are de-pressurized to effect braking by means of springs 21 which pivot plates 15 into engagement with wheels 20 to move the latter into engagement with rail 10. Wheels 20 continue to rotate but are heavily braked. Skidding is prevented by arranging for the coefficient of friction between the plate 15 and the wheel 20 to be less than that between the wheel 20 and the rail 10. In another embodiment, Fig. 4 (not shown), the brakes are positively applied by the hydraulic cylinders against the spring pressure. In both embodiments the wheels 20 may have neoprene tyres and the cylinders 22 may be pneumatically, vacuum or electrically operated. The brakes may be actuated at a predetermined speed by a centrifugal governor driven indirectly by the running wheels.