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Showing papers on "Dynamic braking published in 1978"


Patent
Donald J. Dobner1
25 Jul 1978
TL;DR: In this article, a vehicle braking system with regenerative braking and conventional braking is proposed to integrate the two braking forces to obtain a consistent total braking effort and brake pedal feel with the decrease in vehicle speed.
Abstract: A vehicle braking system with regenerative braking and conventional braking, the system integrating the two braking forces to obtain a consistent total braking effort and brake pedal feel when the regenerative braking force decreases with the decrease in vehicle speed.

35 citations


Patent
Jinbo Y1, Eiji Kozu1, Hiroshi Narita1
01 Aug 1978
TL;DR: In this paper, a series circuit of a diode and an inductance element is connected in series with a d.c. motor, which is operated as a generator during braking operation.
Abstract: A chopper and a series circuit of a dynamic braking resistor and a thyristor are connected in parallel with a d.c. motor which is operated as a generator during braking operation. A series circuit of a diode and an inductance element is connected in series with the d.c. motor. A condenser connected between the ground and the junction of the inductance element and the diode forms a filter circuit together with the inductance element. Current generated by the d.c. motor flows into a d.c. source through the diode and the inductance element during regenerative braking operation. An over-voltage detector fires the braking thyristor when the voltage across the condenser becomes greater than a predetermined limit value, as a result the dynamic braking operation is performed. A chopper controller varies the interval between an ON pulse to turn the chopper into ON state and an OFF pulse to turn the chopper into OFF state for adjusting ON time and OFF time of the chopper in response to the current through the d.c. motor. An operation changer provides a signal to an automatic phase shifter to extend the interval between the ON and OFF pulses to a predetermined period of time enough to quench the braking thyristor when the braking operation of said d.c. motor is changed from the dynamic braking operation to the regenerative braking operation.

30 citations


Patent
18 Aug 1978
TL;DR: In this article, an apparatus for braking a train of vehicles whereby a differentiated braking of the wheels is carried out by servo-mechanical means in such a manner that the rear wheels are the only ones activated directly by the driver during braking is presented.
Abstract: An apparatus for braking a train of vehicles whereby a differentiated braking of the wheels is carried out by servo-mechanical means in such a manner that the rear wheels are the only ones activated directly by the driver during braking. The wheels of the immediately preceding vehicle are then activated in response to drawbar tension forces, and this applies all the way to the first of the train of vehicles. Thereby it is ensured that during braking a tension force is exerted throughout the whole of the train of vehicles, and in this way skidding and jackknifing or fishtailing of the train essentially can be prevented or avoided.

23 citations


Journal ArticleDOI
TL;DR: In this paper, a dc dynamic braking method is proposed and studied that provides very fast braking and experimental results are presented to verify the theoretical predictions and demonstrate the feasibility of the control schemes.
Abstract: A novel control scheme is investigated for operating induction motors in the constant torque mode. The basic control schemes and analysis of the steady-state performance of the system are presented. Circuit models are used to predict the performance characteristics. A new dc dynamic braking method is proposed and studied that provides very fast braking. Experimental results are presented to verify the theoretical predictions and demonstrate the feasibility of the control schemes.

22 citations


Patent
Stephen S. Chen1
25 Aug 1978
TL;DR: In this article, the reference potential is developed in a bridge arrangement wherein the bridge imbalance is detected by a current sensor or by a reference potential generated in another motor circuit where another current sensor is used to detect a variance from the reference value.
Abstract: A diesel electric locomotive has a dynamic braking system including a plurality of traction motors connected across dynamic braking grids. Air blowers for cooling the grids have motors which are connected across the grids. The failure of any motor is detected by monitoring the voltage across the motor with respect to a reference potential. The reference potential is developed in a bridge arrangement wherein the bridge imbalance is detected by a current sensor or by a reference potential generated in another motor circuit where another current sensor is used to detect a variance from the reference value. A circuit responsive to failure signals but voltage isolated from the traction motor circuits actuates an indicator as well as a relay for diminishing or terminating the dynamic braking function.

12 citations


Patent
06 Mar 1978
TL;DR: In this paper, a switch lever on an electrically drive wheelchair incorporates pairs of switch arms so that additional circuitry can be provided for interconnection with the normally provided left and right wheel drive motors.
Abstract: The normally provided manually operable switch lever on an electrically drive wheelchair incorporates pairs of switch arms so that additional circuitry can be provided for interconnection with the normally provided left and right wheel drive motors. This additional circuitry comprises electrical resistances arranged to be connected across the motor leads by the manually operable switch when in an unactuated position for the particular motor in question. The provision of these resistances across the motor leads when the motors are unenergized results in absorption of back voltage spikes to thereby avoid burning out the switch means, dynamic braking when the motors acts as generators as a result of the wheelchair coasting, easier steering control when only one of the motors is energized to effect a turn, and permits the use of permanent magnet type d.c. motors for the left and right wheel drive motors.

12 citations


Patent
09 Feb 1978
TL;DR: In this article, the heat energy dissipation capacity of the provided dynamic braking resistors for a given transit vehicle is established and then the generated motor current supplied to those resistors by the regenerating propulsion motor of the vehicle during the brake mode of operation is controlled to limit as desired in accordance with that capacity the total energy dissipated by the dynamic braking resistor.
Abstract: The heat energy dissipation capacity of the provided dynamic braking resistors for a given transit vehicle is established and then the generated motor current supplied to those resistors by the regenerating propulsion motor of the vehicle during the brake mode of operation is controlled to limit as desired in accordance with that capacity the total energy dissipated by the dynamic braking resistors.

11 citations


Patent
27 Apr 1978
TL;DR: In this article, a stopping or braking arrangement is provided for an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the mechanism to an open position in the absence of motor energization.
Abstract: For an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the damper to an open position in the absence of motor energization, a stopping or braking arrangement is provided which applies DC to the motor for dynamic braking as the damper closely approaches its open position Additionally, the remote possibility of a damper hang-up at an intermediate position resulting from a residual magnetic locking torque is substantially eliminated through the provision of an AC trickle circuit connected to the motor

10 citations


Patent
21 Sep 1978
TL;DR: In this paper, an electrical vehicle is propelled by a constant speed motor receiving current from a storage battery, and an alternator, driven by the vehicle power train through a differential while the vehicle is in motion, is associated with the drive train such that it controls the velocity of the vehicle.
Abstract: An electrical vehicle is propelled by a constant speed motor receiving current from a storage battery. An alternator, driven by the vehicle power train through a differential while the vehicle is in motion, is associated with the drive train such that it controls the velocity of the vehicle. Dynamic braking through increasing field current of the alternator is provided. The alternator is used to recharge the storage battery during periods of less than maximum vehicle velocity and also during deceleration of the vehicle.

8 citations


Patent
07 Jun 1978
TL;DR: In this article, the vehicle is braked by a combination of dynamic retardation and friction brakes, with a simple comparator on each wheel to adjust the relative braking reactions of both systems.
Abstract: The vehicle is braked by a combination of dynamic retardation and friction brakes, with a simple comparator on each wheel to adjust the relative braking reactions of both systems. For emergency braking the dynamic effects are removed so that a controlled braking balance is possible between the front and rear brakes. The dynamic brake reduces brake pad wear and provides a smoother driving control. The inhibit interlock prevents rear wheel lock in full braking, with the anti-skid control being able to reduce the rear brake force to any minimum level.

8 citations


Patent
03 Oct 1978
TL;DR: In this paper, a tape transport is provided which combines dynamic braking with specially configured mechanical braking means, particularly with very thin magnetic tapes, in order to obtain smooth and positive braking, and a pair of linked-together pivot arms are pulled into engagement with the reel drums by springs to obtain holding torque when the reels are at rest.
Abstract: In order to obtain smooth and positive braking, particularly with very thin magnetic tapes, a tape transport is provided which combines dynamic braking with specially configured mechanical braking means. During normal operation, dynamic braking is employed to bring the supply and take-up reel motors to a stop. A motion sensor detects the instant the reels stop and deenergizes a solenoid which holds the mechanical braking sub-system out of action during play and reeling operations. When the solenoid is deenergized, a pair of linked-together pivot arms are pulled into engagement with the reel drums by springs to obtain holding torque when the reels are at rest. The reel-engaging ends of the pivot arms are fitted with brake pads arranged to obtain differential braking torque between the supply and take-up reels according to the tape directions, a feature which is particularly useful when power failure occurs during tape handling operations. Loss of power automatically releases the solenoid permitting the mechanical system to brake the reels to a stop without tape spillage. A varient configuration employs individual solenoids to actuate similar mechanical braking means fitted to the lower ends of the supply and take-up reel motors.

Patent
03 Jul 1978
TL;DR: In this paper, a speed control system for an electric motor is provided for use, for example, in dental offices to control dental drill motors, and the like, which in one embodiment provides speed control from either a foot operated potentiometer or a panel hand-operated potentiometers.
Abstract: A speed control system for an electric motor is provided for use, for example, in dental offices to control dental drill motors, and the like, which in one embodiment provides speed control from either a foot-operated potentiometer or a panel hand-operated potentiometer. The system includes a negative resistance generating circuit which maintains constant speed of the motor for any particular speed setting in the presence of variations in the mechanical load on the motor. The circuit also provides dynamic braking which immediately slows the motor and brings the motor to an almost immediate stop when the speed control potentiometers are returned to their neutral positions. A guardian circuit is also provided in the system which prevents motor burn-up in the presence of a sustained overload condition.

Journal ArticleDOI
TL;DR: In this article, the authors deal with the simulation of the behaviour of tractor-semitrailer vehicles at braking on wet, slippery road surface and show the influence of cornering on the behaviour during braking in a turn.
Abstract: SUMMARY Simulation of Steering and Braking Behaviour of Tractor-Semitrailer Vehicles in Extreme Situations This paper deals with the simulation of the behaviour of tractor-semitrailer vehicles at braking on wet, slippery road surface. The nonlinear model used for the computation enables to simulate extreme situations at wheel locking and swerving The instabilities during braking such as jackknifing and trailer swing as well as non steerability are investigated. Straightline braking shows the influence of cornering on the behaviour during braking in a turn.

Patent
25 Aug 1978
TL;DR: In this article, a variable resistance controller for electrical braking systems and the like is presented, where the form on which the resistance wire is wound has spaced apart flats into which some of the coils are drawn during winding, providing alternate lands and depressions over which a leaf spring type contact rolls.
Abstract: A variable resistance controller for electrical braking systems and the like wherein the form on which the resistance wire is wound has spaced apart flats into which some of the coils are drawn during winding. This arrangement provides alternate lands and depressions over which a leaf spring type contact rolls. The preferred arrangement has only two coils per land to give increased contact pressure of the leaf spring therewith and to provide predetermined incremental increases in electrical output as the leaf spring rolls from one land to the other. In the preferred embodiment, the spacing of the lands is arranged so that the electrical output is proportional to the hydraulic actuating pressure. The preferred embodiment also includes a diode connected between the output of the controller and ground through a fusible link to permit the collapsing magnetic field of the controlled braking electromagnets to draw current through the diode on deactuation of the unit to bypass the wound resistor. This reduces arcing and increases service life.

Patent
15 Jun 1978
TL;DR: In this article, a vehicle load responsive brake control device for adjusting the braking force according to the varying load of the vehicle in each braking range is proposed, which is used to ensure control of the braking action in such a manner that, independently of the existing vehicle load, the actuating force required is always approximately the same.
Abstract: A vehicle load responsive brake control device for adjusting the braking force according to the varying load of the vehicle in each braking range; its purpose is also to ensure control of the braking action in such a manner that, independently of the existing vehicle load, the actuating force required is always approximately the same. Another purpose of the brake control device is to adjust the braking forces in accordance with the dynamic shifting of the axle loads.

Proceedings ArticleDOI
01 Feb 1978
TL;DR: In this paper, an automatic field control (AFC) regenerative braking system is introduced for electric vehicles, which uses a shunt motor, the field current is controlled inversely proportional to motor speed and regenerative operation is obtained by low motor speed.
Abstract: Generally in electric vehicles regenerative braking is incorporated to increase urban driving range on a single charge and to get the same brake torque as engine brake. An analysis of the regenerative operation by thyristor chopper control is described. Firstly, to clarify regenerative efficiency, the calculation of various losses such as commutation loss and thyristor loss which arises at the braking mode is discussed. The regenerative efficiency calculated from the above losses agrees closely with test results. Secondly, a newly developed automatic field control (AFC) regenerative braking system is introduced. This AFC regenerative control system uses a shunt motor, the field current is controlled inversely proportional to motor speed and regenerative operation is obtainable by low motor speed. This system is suitable for electric vehicles. Thirdly, it is noted that utilizing this AFC regenerative brake control, actual urban driving range can be increased by approximately 16%.

Patent
22 Mar 1978
TL;DR: In this paper, an analog/digital numerical control system that utilizes analog techniques to process large scale (macro) differences and digital technique to process small scale (micro) differences is presented.
Abstract: An analog/digital numerical control system that utilizes analog techniques to process large scale (macro) differences and digital techniques to process small scale (micro) differences. In this manner, advantage is taken of the respective virtues of both analog and digital processing techniques while avoiding the disadvantages associated with the exclusive use of either approach. In addition, a novel tach responsive braking generator is disclosed for particular use in controlling the positioning of high mass heads that is adapted to provide dynamic braking of the controlled machine assembly to accomplish proper positioning without "hunting".


Journal Article
TL;DR: In this paper, the simulation of the behaviour of tractor-semitrailer vehicles at braking on wet, slippery road surface is presented, which enables a user to simulate extreme situations at wheel locking and swerving.
Abstract: This paper deals with the simulation of the behaviour of tractor-semitrailer vehicles at braking on wet, slippery road surface. The nonlinear model used for the computation enables a user to simulate extreme situations at wheel locking and swerving. The instabilities during braking such as jackknifing and trailer swing as well as non steerability are investigated. Straightline braking shows the influence of cornering on the behaviour during braking in a turn. /TRRL/

01 Aug 1978
TL;DR: In this paper, full scale braking tests are reported for a Norton 850 motorcycle fitted with an antilock brake system on the front and rear wheels on both dry and wet surfaces.
Abstract: Full scale braking tests are reported for a Norton 850 motorcycle fitted with an antilock brake system on the front and rear wheels. The tests included straight line braking and braking in a turn, on both dry and wet surfaces. Various braking methods were used in addition to the antilock system, including open loop (with brake force limiters) and closed loop control by an expert test rider. On low coefficient wet surfaces, the antilock system gave braking performance which was significantly better than that which could be achieved by either an expert rider or suitably tuned open loop braking procedures.

Patent
20 Apr 1978
TL;DR: In this paper, the authors propose to lighten a shock of a braking time by decreasing a field currrent at the starting time of a dynamic braking, which can be used to reduce the impact of a collision.
Abstract: PURPOSE:To lighten a shock of a braking time, by decreasing a field currrent at a starting time of a dynamic braking.

Book ChapterDOI
01 Jan 1978
TL;DR: In this article, an advantageous circuit of the input converter is described, which transforms the line voltage to a higher value of the d.c. link voltage (step-up-chopper).
Abstract: Asynchronous motors of traction vehicles are preferably fed by pulse-mode operated inverters with a constant d.c. input voltage. Also in the case of a contactwire with a d.c. supply voltage an input-converter is favourable. An advantageous circuit of the input converter is described, which transform the line voltage to a higher value of the d.c. link voltage (step-up-chopper). It consists of two choppers with phase displaced chopping. They have a common commutation-circuit. In the case of dynamic braking the power-conversion in the resistance is controlled by the chopper. The chopper takes from the line a rippeled d.c. current. Its ripple-components could disturb the signalizing systems and communication-circuits. This a.c. components are caused mainly by the chopper, and in a smaler part by the inverter and the interference of both. The mode of generation of these harmonic components in the case of constant chopping-ratio will be described. In addition the a.c. components are influenced by the ripple of the line voltage and the converter control system. The harmonics can be reduced by special filtering circuits. In case of very low frequencies this would result in large filter elements. A reduction of the currents by a special control -circuit will be described.