Showing papers on "Dynamic braking published in 1982"

Interlock braking system for motorcycles

Abstract: An interlock braking system for motorcycles comprising a brake pedal, a single master cylinder which generates a braking pressure according to an external force applied to the brake pedal, first and second brake mechanisms connected to the master cylinder for applying first and second braking forces according to the braking pressure to the front and rear wheels, respectively, and an anti-lock mechanism for changing the braking pressure according to rotational speeds of the front and rear wheels to prevent the wheels from becoming locked. In this manner, the interlock braking system effectively avoids the occurrence of a wheel-lock condition when braking the front and rear wheels of a motorcycle.

Vehicle braking system and method of braking

Abstract: A vehicle braking system having one brake circuit actuated directly by pressure generated in a master cylinder and a second brake circuit actuated, by pressure generated by actuation of the master cylinder, to the extent that regenerative braking effort acting on the wheels having brakes in the second brake circuit is insufficient to provide the desired total braking effort on those wheels. When regenerative braking on those wheels is sufficient to meet the braking effort demand, the service brake system does not supply any additional braking effort. A compliance control member provides the feel of input travel and force equivalent to the regenerative braking effort actually at the wheels of the second brake circuit when regenerative braking is occuring while the vehicle is being braked. The absorbed displacement and force is fed back to the second brake circuit by the compliance control member when the regenerative braking effort becomes insufficient to meet the braking effort demanded from the brakes of the second brake circuit.

Power fail servo system

Abstract: A power fail circuit provides protection for tape such as used in the tape transport apparatus of a video recorder in the event of a failure of the external power supply. The tape transport apparatus includes as a feature the provision of an electrical error signal used to govern drive motors to maintain substantially constant tape tension when the system is operating normally. After power failure occurs, the power fail circuit continues to respond to the error signal by coupling current from the drive motors to provide dynamic braking. Further, current taken from the drive motors selectively is coupled to an energy storage device operatively associated with the system power supply, to provide augmenting energy from the kinetic energy of the motors for continued control of the power fail circuit as the drive motors are caused to decelerate under control to stop.

Anti creep vehicle braking system allowing further additional braking action application

Abstract: An anti creep braking system for a vehicle. A force transmission member is drivingly coupled to a part of the brake pedal and transmits braking force to a braking force generation system. A braked member is selectively braked by a braking device, and is driven by the brake pedal with a one direction force transmission device being interposed on the path of transmission of force between the brake pedal and the braked member. The sense of force transmission of the one direction force transmission device is such that, when the movement of the braked member with respect to the vehicle is prevented by the braking device, the brake pedal may be further depressed to increase vehicle braking action without transmitting substantial force to the braked member, but may not be moved backwards to reduce vehicle braking action. A control system selectively controls the braking device so as to put it into operation and to release it from operation according to the operational conditions of the vehicle effected by the driver of the vehicle and/or skidding condition of the vehicle.

Review of NASA Antiskid Braking Research

Abstract: NASA antiskid braking system research programs are reviewed. These programs include experimental studies of four antiskid systems on the Langley Landing Loads Track, flights tests with a DC-9 airplane, and computer simulation studies. Results from these research efforts include identification of factors contributing to degraded antiskid performance under adverse weather conditions, tire tread temperature measurements during antiskid braking on dry runway surfaces, and an assessment of the accuracy of various brake pressure-torque computer models. This information should lead to the development of better antiskid systems in the future.

Control apparatus for electric motor car

Abstract: PURPOSE:To make regenerative and dynamic two-functioned braking possible without additional implementation of a chopper for dynamic braking. CONSTITUTION:A chopper 5 and a thyristor 12 are switched off on regenerative braking and chopper 4 is controlled to be switched on and off. Consequently each DC motor 2, 3 regenerates a power through each diode 6, 7 to be dumpud gradually when the chopper 4 is switched off and a power is regenerated through the DC motor 2, the chopper 4 and the DC motor 3 when the chopper 4 is switch on. When a load which absorbs a regenerated power is made to be less a thyristor 12 and choppers 4, 5 is controlled to be on and off and dynamic braking is controlled by varying a current which is flowing on registors 8, 11 for dynamic braking. By this arrangement regenerative and dynamic two-functioned braking is make possible without additional implementation of a chopper for a dynamic braking.

Controlling device for electric motor vehicle

Abstract: PURPOSE:To facilitate regenerative and dynamic braking by a method wherein motors are divided into two groups, which are controlled respectively by two choppers Nos. 1 and 2 when the vehicle is on a power run and are incorporated through diodes in two regenerative circuits when the vehicle is put on the brake. CONSTITUTION:Motors 2 and 3 and a chopper 4, connected in series, are coupled to a power supply 1. Diodes 6 and 7 are connected to the circuit with their polarity oriented as prescribed, and a chopper 5 and a resistor 9 are connected in series and placed across the power supply 1. Motors 2 and 3 output voltage flows into a load 10 when the chopper 4 is on. When the chopper 4 is off, current is reduced through a diode 7-motor 3 regenerative circuit and a diode 6-motor 2 regenerative circuit. A sudden decrease in the load 10 can be met by the turning on and off of the choppers 4 and 5 that result in a regenerative-dynamic brake combination. Thus, a simple netwoek can be realized in which no additional choppers are needed to effect dynamic braking.

Control method for dc motor

Abstract: PURPOSE:To stop a DC motor in an extremely short period of time without reversing said motor, by a method wherein the DC motor is fed with a reverse exciting current from a power source in the flowing direction of a dynamic braking current, and the reverse excitation is stopped immediately before the stoppage of the motor, with only the dynamic braking current allowed to flow. CONSTITUTION:To stop a DC motor M under a forward rotating state where switches SW1, SW4 are on while switches SW2, SW3 are OFF, first, the switches SW1, SW4 are also turned OFF to cut off the motor M from a power source, and the switches SW2, SW3 are turned ON thereafter. Thereby, a reverse current IVC flows through the motor M from the power source as well as a dynamic braking current IB of the motor M itself flows through a closed loop consisting of the switch SW2 a diode D3 the motor M, so that the motor M is rapidly decelerated. Before the motor M starts reversing, the switch SW3 is turned OFF to cut it off from the power source, with only the dynamic braking current allowed to flow. Acordingly, it is possible to stop the motor M without reversing the same.

Device for adjusting the braking time of a brake on a conveyor

Abstract: The invention relates to a braking device for a conveyor, which device, in the event of braking, brakes the conveyor in a predeterminable braking time, which is independent of the conveyor speed and the load, until standstill. During the braking time, the braking device checks the braking deceleration in the effective braking moment and, taking into consideration the braking time which has already elapsed and the present braking deceleration, calculates the remaining braking time until standstill. If the remaining braking time falls below or exceeds the predetermined braking time, a corresponding adjusting signal for correcting the braking force is produced.

Controlling method for synchronous machine

Abstract: PURPOSE:To decrease a stopping time and realize an effective stopping control in a synchronous machine by dynamic braking an induction motor linked with the synchronous machine by means of an exciting system of the synchronous machine and then by dynamic braking the synchronous maching using a start-up adjusting resistor of the induction motor. CONSTITUTION:During a stopping control time, a braker 13 is opened by a stop command to disconnect a synchronous machine 1 from a system, and at the same time a breaker 12 is opened to stop supply of a field current from a thyristor exciting unit 9. Further, a switching connector 26 is turned to a firing angle control circuit 27a side, a breaker 28 is switched on, and an induction motor 2 is dynamic braked via the thyristor exciting unit 9. Through this procedure, the revolution speed of the synchronous machine 1 is reduced to 30-50% of the rated value. Afterwards, opening the breaker 28, switching on a breaker 30, turning the switching connector 26 to a firing angle control circuit 27b side, controlling the firing of the thyristor exciting unit 9 and also switching on the breaker 12, to supply a field current, the synchronous machine 1 is dynamic braked to complete stop.

Three-phase induction motor speed control device

Abstract: PURPOSE:To shorten length of time for shifting form high-speed operation to low- speed operation, by switching the operation temporarily to a speed of a large-width control torque when making a changeover of the operation from the high speed to the low speed by thinned out power supply CONSTITUTION:A mode changer F which changes an input signal of a six-cycle ring counter D from an output of a 1/n frequency divider C to an output signal of a reference signal generating device B, a dynamic braking device 1 which actuates an ignition phase adjuster G, a signal generating device E which sends out reference signals by phases having prescribed phasic difference with one cycle of (6n-1)/2[or (6n+1)/2]of a power source voltage, and a poulse generating device H which generates an ignition pulse from a logic product of this reference signal and an ignition phase adjusting signal are all provided And, after speed of an electric motor is reduced form 1/5(1/7) ratio to 1/11(1/13) ratio of the rated speed by changeover of the mode changer F, it is stopped by the dynamic braking

A regenerative braking system for d.c. railway traction

Abstract: A regenerative braking system using a chopper-controlled d.c. series motor is described. A feature of the system is the automatic change from a weak-field to a full-field mode of operation as the speed falls. Sudden changes in line voltage can be accommodated with some of the flexibility of a separately-excited motor scheme, but at less cost. A second chopper circuit controls the effective resistance of a braking rheostat so that regenerative and rheostatic braking can be blended and the greatest possible energy savings can be made, within the limits imposed by the receptivity of the traction supply system.

Controlling method of synchronous machine

Abstract: PURPOSE:To lessen a stopping time of a synchronous machine effectively and unforcedly by dynamic braking an induction motor linked to the synchronous machine and at the same time by short circuting the synchronous machine during the earlier time of the stopping control and by dynamic braking the synchronous during the late time of the stopping control. CONSTITUTION:During the earlier time of the stopping control, a breaker 13 is opened to diconnect a synchronous machine 1 from a system, and also a breaker 12 is opened to stop the supply of a field current from a thyristor exciting device 9. Besides, dynamic braking is applied to an induction motor 2 via the thyristor exciting device 9 by changing a switching connector 26 to a firing angle control circuit 27a and switching on a breaker 28. During the period in which the revolution speed of the synchronous machine 1 decreases down to 30-50% of the rated revolution speed, a disconnecting switch 30 is switched on to short-circuit the synchronous machine 1, and then a breaker 28 is opened and a switching connector 26 is changed to a firing angle control circuit 27b side to control firing of the thyristor exciting device 9 and at the same time the breaker 12 is switched on to supply a field current. Thus, the synchronous machine 1 is dynamic braked down to a complete stop.

Controller for ingot drawing torque of continuous casting machine

Abstract: PURPOSE:To prevent the generation of backlash and improve the quality of ingots by providing a speed controller to an apron roller and increasing drawing resistance. CONSTITUTION:An apron roller is overdriven with gears in a gear box 30, and is connected to a DC motor 6A. The motor is driven by a thyristor device 31. The speed feedback value from a pilot generator 38 and the command value from a dynamic braking quantity setter 37 are compared and controlled in a thyristor controller 35, and the dynamic braking quantity corresponding to ingot speeds is obtained via an electric current controller 34. In such controlling, the periperal speed of the apron roller is set at about 90-80% the ingot speed.