Showing papers on "Dynamic braking published in 1987"

Apparatus and method for conserving fuel during dynamic braking of locomotives

Abstract: A respective microcomputer-based dynamic braking proportioning unit is disposed on each locomotive of a group of locomotives of a train consist. Each unit is connected to the brake setup and brake control wires of a trainline communicating with all of the locomotives, and each unit is connected to the dynamic braking equipment of its respective locomotive. Each unit includes two data entry mechanisms, such as switches, by which the respective microcomputer is advised of the total number of locomotives and of a unique number identifying the respective locomotive within the group. From the two signals from the trainline and the total locomotive and unique locomotive identification data, the respective microcomputer determines and outputs appropriate dynamic brake equipment control signals for the respective locomotive. These control signals are generated so that not all of the locomotives necessarily need to be placed in a dynamic braking mode for all levels of total dynamic braking required, thereby allowing any unneeded locomotive to be operated at a lower fuel consuming power level.

Apparatus for the measurement and/or regulation of a braking force and/or of a braking torque

Abstract: An apparatus which measures and regulates the braking torque of a brake unit in long-term operational use. The brake unit includes both a brakable element and the braking device. An output signal from at least one temperature-dependent measuring element, located on or in one of the brakable elements and the braking device, is supplied to an evaluation apparatus. The evaluation apparatus determines, from the current value of the output signal of the temperature-measuring element, a present braking torque, and adjusts such torque when desirable.

Dynamic brake control

Abstract: A dynamic brake control system for an alternating current motor powered by a variable voltage, variable frequency inverter which regulates the speed of the motor An AC to DC converter converts AC line power to DC power with the DC power being transferred to the inverter via a DC link During electrical dynamic braking, the inverter functions to transfer power from the motor to the DC link The torque available to the motor during braking is a function of the receptivity of the DC link Link receptivity controlled by a resistance connected to the link in which the resistance is modulated at a frequency dependent upon the incoming AC line frequency at the converter The modulation is binarily controlled so as to minimize ripple current on the DC link without the necessity of providing high frequency control of the modulating electronics

Adaptive mode anti-lock brake controller

Abstract: A wheel lock control system is described which utilizes both independent and select low modes of wheel lock controlled braking. When braking on a surface in which the coefficients of friction between the two sides of the vehicle are substantially different or when the vehicle is undergoing severe steering maneuvers while braking, the wheel lock control system utilizes a select low mode of braking for the vehicle rear wheels so as to maintain vehicle stability. However, when the four wheels are being braked on a substantially uniform coefficient of friction surface, the wheel lock control system utilizes an independent mode of braking for each of the wheels of the vehicle so as to minimize the vehicle braking distance.

Movable storage unit control system

Abstract: A movable storage unit control system is provided with: a leading edge safety tape switch for contacting it to bring a driven unit to a stop; a processor for generating move and stop command signals; a plurality of circuits through which test signals are transmitted under control of the processor and which are returned to the processor coincidentally with their transmission through a current sensor if the circuit tests good; a procedure for having the processor address a test signal to a nonexistent circuit to determine if the current sensor has failed and is allowing return of signals when it should not; circuits for setting minimum and maximum speed of the motors that drive the storage units; a circuit for setting the intensity of dynamic braking of the drive motors; and, a watchdog circuit that shuts down the processor upon occurrence of intense temporary electrical noise or software execution errors and is involved in causing the processor to shut down and block all commands to the system if the processor or other hardware fails.

Conveyance with electronic control for left and right motors

Abstract: A conveyance (10) is provided with: automatic limiting (223) of the rate of change in power supplied to left (26a or 232a) and right propulsion motors, whether electrically or hydraulically propelled; dynamic braking of electric propulsion motors (26a and 26b) that is achieved by shorting a motor winding (150a) during a portion (233a) of an interval (217a) between power pulses (207a) of a pulse-width-modulated driving voltage (209a); power-off braking that is achieved by shorting a motor winding (150a) when no power pulses are being supplied; extended life of relays (144a & 148a) that is achieved by preventing current flow to the motors during opening and closing of the relay contacts (154a and 156a); and a solid-state switching device (168a and 170a) that is controlled by a signal in a single conductor (200a) and that provides an effective delay (219a and 221a) in switching between two circuits (152a and 160a).

Movable storage unit control system with system resetting watchdog circuit

Abstract: A movable storage unit control system is provided with: a leading edge safety tape switch for contacting it to bring a driven unit to a stop; a processor for generating move and stop command signals; a plurality of circuits through which test signals are transmitted under control of the processor and which are returned to the processor coincidentally with their transmission through a current sensor if the circuit tests good; a procedure for having the processor address a test signal to a nonexistent circuit to determine if the current sensor has failed and is allowing return of signals when it should not; circuits for setting minimum and maximum speed of the motors that drive the storage units; a circuit for setting the intensity of dynamic braking of the drive motors; and, a watchdog circuit that shuts down the processor upon occurrence of intense temporary electrical noise or software execution errors and is involved in causing the processor to shut down and block all commands to the system if the processor or other hardware fails.

Electric braking control

Abstract: An apparatus for an electric drive vehicle which provides linear deceleration via electrical braking. The apparatus monitors vehicle speed and adjusts the duty cycle of a chopper circuit according to look-up tables. These table correlate vehicle speed and desired deceleration rate to braking torque, thereby enabling the apparatus to maintain a preselected deceleration through the entire stopping distance and to precisely position the vehicle.

Anti-lock braking systems for vehicles

Abstract: A vehicle anti-lock braking system is disclosed in which a supply of fluid from a master cylinder is modulated in accordance with signals from wheel speed sensors to affect brake release and re-application during an anti-lock mode. An electric motor drives a first pump to provide a source of power during the anti-lock mode, and a second pump to charge a hydraulic acumulator. The pressure stored in the accumulator may be used to provide assistance when applying the brakes, and may also be used to apply a portion of the braking system.

Device for holding braking force for vehicle

Abstract: A device for holding the braking force of a motor vehicle has a braking force holding valve in a brake operating fluid circuit. The device ascertains whether a load is imposed on an engine of the motor vehicle based on detected signals indicating the amount of depression of an accelerator pedal and the rotational speed of the engine. When there is a load acting on the engine, the braking force holding device is opened to release a braking force.

Conveyance with electronic control for motors

Abstract: A conveyance (360) is provided with: dynamic braking of electric propulsion motors (26a and 26b) that is achieved by shorting a motor winding (150a) during a portion (233a) of an interval (217a) between pulses (207a) of a pulse-width modulated driving voltage (209a); automatic limiting (223) of the rate of change in power supplied to left (26a or 232a) and right (26b) propulsion motors, whether electrically or hydraulically propelled; power-off braking that is achieved by shorting a motor winding (150a) when power pulses are not being supplied; extended life of relays (144a and 148a) that is achieved by preventing current flow to the motors during opening and closing of the relay contacts (154a and 156a); and a solid-state switching device (168a and 170a) that is controlled by a signal in a single conductor (200a) and that provides an effective delay (219a and 221a) in switching between two circuits (152a and 160a).

Dynamic braking circuit for universal motor

Abstract: A dynamic braking circuit for a universal motor is disclosed. A switching mechanism is used to reverse the orientation of the series field winding with respect to the rotor when power is removed. Because the rotor acts as a generator when power is removed, it will generate current to the field winding. Because the orientation of the field winding has been reversed, the field winding will thus try to make the motor run in the opposite direction, thereby exerting a braking force on the motor. The amount of the braking force is limited by using a portion of a second winding to oppose the reversed action of the first winding.

Control apparatus for maintaining braking force

Abstract: A control apparatus is provided for maintaining a braking force in an automotive vehicle for calculating the rate at which vehicle velocity decreases when braking is applied, and for inhibiting braking force maintenance control within a predetermined period of time after brake release when the rate of velocity decrease exceeds a predetermined value. The braking force maintaining function is prevented from operating erroneously by distinguishing between a state in which the vehicle is at rest and a state in which the vehicle wheels are locked up.

Vehicle braking power control device utilizing motor braking power

Abstract: PURPOSE:To reduce the cost of a brake system as well as the shock in braking, by detecting the rotating speeds of the respective axles upon braking to control braking power. CONSTITUTION:Left and right front wheels are driven by the engine 6 while left and right rear wheels are driven by exclusive motors 8, 9. When a brake pedal 14 is operated, a signal, proportional to the treading amount of the brake pedal, is inputted from a potentiometer 15 into a control circuit 12. The control circuit 12 controls a hydraulic control unit 13 and motors 8, 9 based on the rotating speeds of respective axles upon braking whereby braking power is controlled. In this case, the rotating speed of the front wheel is compared with that of the rear wheel and when the rotating speed of the side of the wheel driven by the motor is lower or zero, the braking of the side of the motor is determined as excessive, therefore, motor braking power is reduced.

Auxiliary hydrostatic drive system

Abstract: A combine includes a variable displacement, reversible delivery pump which drives main drive wheels via a main hydraulic drive unit and which drives a pair of steerable wheels via auxiliary hydraulic drive units. A pair of pressure-limiting and relieving valves are connected between the auxiliary drive units and the pump so that auxiliary drive units with lower pressure ratings than that of the main drive units can be used. The valves relieve pressure from the auxiliary drive units during dynamic braking.

Inverter for elevator driving

Abstract: PURPOSE: To make certain detection of the power abnormalities and to reduce excessively the emergency shutdowns by starting the retarded motion waiting a certain time since the power abnormalities are detected and restoring to the normal operation without decelerating in a short instantaneous service interruption. CONSTITUTION: A control section 10 continues the normal control limiting the output current of an inverter section 3 within a certain time after detecting the power abnormalities. When the power abnormalities restored to the normal conditions during the time, the control section 10 releases a dynamic braking instruction as well as restarts the regenerative control of a converter section 1. And, when the power abnormalities still keep on after a certain time, the control section 10 releases the current limitation of the inverter section 3 as well as decreases the speed instruction. And, a transistor 7 is switched on by generating the regenerative current according to the operation to make the retarded shutdown by the dynamic braking. COPYRIGHT: (C)1988,JPO&Japio

Cooling deice of resistor for electric rolling stock

Abstract: PURPOSE:To improve the cooling effect of a resistor by driving a fan-driving motor in response to the quantity of a current of the resistor during dynamic braking and by means of a constant-voltage supply source when the current do not flow through the resistor. CONSTITUTION:When the state of dynamic braking is brought, a line breaker 11 is closed, and a current I corresponding to a travel speed of a vehicle flows through a resistor 12, thus generating braking force. DC voltage Vr proportional to the current I is generated simultaneously in a center tap 12a for the resistor 12. When the DC voltage Vr exceeds a voltage V4 through a rectifying circuit 16 from a quaternary winding 6, it is applied as an input voltage Vi to an inverter 19. Accordingly, heat generated by the resistor 12 during dynamic braking is cooled by the revolution of a fan 14 corresponding to a calorific value of the heat, and the remain heat of the resistor 12 is removed by the fan 14 driven at the constant voltage V4 after the completion of braking.

Braking method for ac electric railway car

Abstract: PURPOSE:To utilize the energy of a rotor effectively by using inverter regenerative power as power for dynamic braking when there is no regenerative load in an AC power supply. CONSTITUTION:Inverters 8a, 8b are controlled in response to brake pattern signals outputted from a brake pattern generator 13 by gate control sections 16a, 16b on regenerative braking. When there is no regenerative load in an AC stringing and DC voltage rises and an over-voltage detecting section 14 is operated, a regenerative-dynamic braking chamber 17 is changed over. Accordingly, the inverter 8a supplies two phase of induction motors 9a-1, 9a-l with voltage by a gate control section 15 for controlling dynamic braking, and conducts dynamic-braking operation.

Partly dynamic brake lights for vehicles

Abstract: The invention is concerned with indicating the braking process in vehicles. The intensity and duration of the braking process can be perceived visually. Depending on the intensity of the process, one or more light faces are made to light up in a specific sequence so that the precise perception of the dynamic braking process is conveyed to the traffic travelling behind. The signal required for this is obtained from a generally known acceleration sensor. An electronic evaluation circuit produces the pulses to drive the various lighting elements. Since the eye responds best to intermittent light faces, the driver of the vehicle travelling behind can react here more quickly and with appropriate braking force.

Induction motor-type electric rolling stock controller

Abstract: PURPOSE:To improve a control performance of dynamic braking by controlling an energy consumed by a resistor with a specific resistance value inserted in a DC side. CONSTITUTION:In power running, a line breaker 3 is closed and a three-phase AC power with variable voltage and frequency is supplied from an inverter 10 to an induction motor 11. In this case, a slip frequency fs is added to an output frequency fr of pulse generator 12 to output an inverter frequency finv. In regenerative braking, the slip frequency fs is subtracted from a rotor frequency fr to output the inverter frequency finv. When there is no regenerative load on an electric overhead line side, the line breaker 3 is opened and a line breaker 7 is inputted while rotational energy is consumed by a brake resistance 8. At that time, the inverter 10 is controlled so that a power consumption of the brake resistance 8 is proportional to velocity.

Braking device for electrical rail vehicles consisting of tractive unit and trailer car

Abstract: In a braking device for electrical rail vehicles consisting of tractive unit and trailer car, for generator braking of the tractive unit a braking voltage which is proportional to the generator current is produced and a control current which is dependent on the braking voltage is fed to braking solenoids provided in the trailer car. The deceleration arising in known braking devices as a function of the strength of the current (shown by broken line) produces bad braking behaviour of the trailer car. In order to linearise the deceleration and thus to substantially improve the braking behaviour, control elements which reduce the control current in the lower range of the braking voltage are arranged in a feed line from the basic brake resistor to the solenoids. As a result, the characteristic deceleration line for the trailer car which is shown by an unbroken line is produced.

Braking device for use in vehicle

Abstract: An anti-skid braking device for use in a vehicle comprising a braking mechanism for supplying a braking force to a wheel of the vehicle, a moderator for moderating the braking force supplied from the braking mechanism to the wheel for a moderation time interval in a case where the acceleration relevant to the rotation of the wheel reaches a predetermined negative angular acceleration value during supply of the braking force to the wheel by the mechanism.

Resistance network supported on frame

Abstract: The dynamic braking system used on electric locomotive and internal combustion locomotive supported by rigid frame often consists of mutual insulated or shock-proof metal members and resistance tapes which are insulated and shock-proof to the frame. For insulating and shock-proofing the frame and metal members, it is best by using plastic molded or pressed laminated organic insulating materials, ie, one kind of polyester or the like, and protected by metal heat-dissipated plates. Where the portion is subjected to high temp. ceramic materials are used to reinforce the organic insulators.

An analysis of cornering performance during braking

Abstract: A number of studies have been made on cornerability during braking, and it is known that the degree of yaw rate change reaches a peak at a certain value of braking decleration. In this paper, a theoretical analysis is carried out on the mechanism generating this peak. It was found that providing the proper roll steer and compliance steer characteristics of the rear suspension is an effective means of lowering this peak value.

Analysis of the stability of braking systems in car and caravan combination

Abstract: SUMMARY In the present article, a mathematical model of the car-caravan combination has been constructed. In simulating the transmission of forces in the articulation of the joint, special attention has been focussed on two types of action in the braking system of the caravan: the conventional braking through overrun and a prototype with hydraulic action. The model of the articulation has been compared with tests carried out on a real vehicle. This model has been constructed by means of a computer programme with different braking maneuvers with the view to analyse the influence of one system or the other on the general behaviour of the vehicle.

Brake device for obtaining braking effect accurately corresponding to operating force

Abstract: PURPOSE: To reduce delay in operation and improve safety by controlling a brake operating force through a braking effect suited to each time, with the lapse of time from the start of a braking operation. CONSTITUTION: The start of operation of a brake operating member is detected by a start of operation detecting means and the lapse of time from the start of operation is measure by a time measuring means. And, the zone of the lapse of time is divided into plural stages and, in accordance with each stage,a target braking effect is determined to be a value suited to each stage by a target braking effect determining means. And, a brake driving device is controlled through a brake driving device control means so that an actual braking effect is equal to the target braking effect, by a braking effect detecting means. Accordingly, a braking effect suited to each time during braking can be obtained while also reducing delay in the operation of a brake, improving the safety of an automobile. COPYRIGHT: (C)1988,JPO&Japio