Showing papers on "Dynamic braking published in 1981"

Electrically powered vehicle control

Abstract: An electric control is disclosed for an electrically powered vehicle having independently controlled left and right drive motors and associated drive wheels to propel and steer the vehicle. The electrical control includes left and right closed loop control circuits for respectively accelerating either or both of the drive wheels whenever a speed command or error signal associated with such drive wheel exceeds a first determined value. Dynamic braking is provided by connecting in parallel electrical relationship an associated brake resistor across one or both of the motors whenever the speed command signal associated with such motor does not exceed a second predetermined value.

Electrical braking transitioning control

Abstract: An electrical braking circuit provides smooth transitioning between regenerative and plug braking of a DC electric motor by use of a low ohmic value resistance path to maintain motor torque during transitioning. During initiation of electrical braking, a similar low ohmic resistance path momentarily connects the motor to a power source in order to establish proper magnetic flux in the motor to enable regenerative braking. Both resistance paths are disabled during motoring and braking modes of operation in order to minimize power loss in the resistance paths.

Composite control for soft start and dynamic braking of a three-phase induction motor

Abstract: A control circuit for a three phase induction motor includes a voltage controller having a silicon controlled rectifier in each of a first, second and third supply line connected to the motor. The control circuit further includes a first, second and third phase control means for controlling the firing angles of the respective silicon controlled rectifiers, a circuit for providing a positive ramp signal, and a circuit for providing a constant level signal. A starter circuit includes a "run" push button and a "brake" push button. The depressing of the "run" push button connects a three phase power supply to the supply lines of the voltage controller and causes the positive ramp signal to be applied to the first, second and third control means to control the firing angles of the silicon controlled rectifiers to provide a soft start for the motor. The subsequent depressing of the "brake" push button renders the second and third phase control means inoperable thus terminating the running of the motor and applies the constant level signal in place of the positive ramp signal to the first phase control means to control the firing angle of the silicon controlled rectifier in the first supply line to thereby provide a D.C. current for braking the cruising motor.

Broke for magnetic disc drive apparatus

Abstract: A rotation control device for a magnetic disk drive apparatus, which provides electrical regenerative braking of the apparatus prior to and continuously with actuation of an electro-mechanical braking system, once power is cut off to the apparatus. The use of electrical regenerative braking minimizes wear on the mechanical braking components and reduces maintenance on the apparatus. The use of electro-mechanical braking at low speeds assures reliable continuous braking when the electrical regenerative braking becomes relatively ineffective at low speeds.

Locomotive energy recovery system

Abstract: An energy recovery system for a diesel electric locomotive is disclosed. The energy recovery system captures and stores the waste heat generated by the diesel engine of the diesel electric locomotive for use at a remote location at a later time. The energy recovery system also converts the electricity generated by the diesel electric locomotive during dynamic braking into heat, and captures and stores this heat for use at a remote location at a later time.

Electric motor dynamic braking energy recuperating system

Abstract: To provide for high efficiency of recuperation of energy stored in the rotating and electromagnetic system of a dynamo electric machine, upon dynamic braking thereof, in which the dynamo electric machine is connected in a chopper-controlled series circuit, a field diode (10) is connected across the field winding (11); a controlled switch (18), for example a transistor or a thyristor, is connected to the junction between the field winding (11) and the aramature (12, 13) and a return line (N) to a storage battery, the controlled switch being controlled to close by a control circuit (19) which opens a brake switch (16) connected between the battery and the dynamo electric machine series circuit under motor operating conditions, to provide for continued current flow through the field, which then is reversely connected by a field reversal switch (8, 9), with continued current flow being maintained by a free-wheeling diode (10) connected across the field. The chopper may be a thyristor (2) connected to a turn-off circuit, the turn-off capacitor (4) also furnishing initial field current through the controlled switch (18) or it may be a transistor (2') which is energized to conduction with a slight delay with respect to closing of the controlled switch (18).

Control circuit for operating a direct current motor during traction or braking

Abstract: A control circuit which permits a direct current motor to operate during traction or during braking in such a manner that energy can be either dissipated or recovered; and, in particular, the invention embodies gradual, continuous, and reversible shifting from one form of braking action to another.

Auxiliary sewing machine motor braking

Abstract: An auxiliary fast stop braking circuit is provided for an electronically controlled sewing machine having the capability to implement a single pattern of a repetitive stitch pattern by implementing needle bar release from its drive means and zero feed motion at the completion of the last stitch of the pattern. The auxiliary fast stop braking circuit is responsive to selection of a single pattern and to activation of the needle bar release solenoid to implement dynamic braking of the sewing machine motor.

All-Digital Simulation of Simple Automobile Maneuvers

Abstract: A new, all-digital simulation describes straight-line acceleration and braking of an automobile. The model has five degrees of freedom: longitudinal velocity, vertical velocity, pitch angular velocity, and the angular velocities of the front and rear wheels. The model is capable of handling severe maneuvers. Special provisions allow the user to include antilock systems, average suspension forces, perform braking studies, and assess the importance of nonlinear terms. A validation study shows a close comparison with results from earlier models. The model is modular, well-documented, and readily available to researchers in a convenient form.

Car-Following Evaluation of Braking Deceleration Level Signals

Abstract: A driving test evaluated brake signaling displays, including deceleration signals, and a simulated brake signal failure. Measures related to car-following and rear-end collision performance were clearly degraded by the brake signal's failure, and there were a few differences between the conventional and experimental configurations.

Anti-locking brake system for a vehicle

Abstract: An anti-locking system controls the service braking pressure for controlling the application of pneumatic braking pressure applied to a wheel vehicle. A valve responsive to the speed of the wheel causes actuation of a fluid pulse generator to generate fluid pulses of predetermined amplitudes and frequency to switch the braking pressure on and off when the vehicle wheel becomes locked.

Emergency brake for cargo conveyor

Abstract: PURPOSE:To enable emergency stoppage even in power failure, by utlizing the inertial motion of a cargo conveyor and using a separately-excited shunt-wound DC motor for running as a self-excited generator to perform dynamic braking. CONSTITUTION:A power failure response switch 13 is provided between a separately-excited shunt-wound DC motor 6 and a power source 12 so that the switch 13 normally connects the motor 6 to the power source 12 but connects the motor 6 to a dynamic braking resistor 14 in power failure. Other power failure response switches 17, 18 are provided between an exciting power source 16 and the exciting shunt winding 15 of the motor 6 so that the switches 17, 18 normally connect the exciting shunt winding 15 to the exciting power source 16 but connect the winding 15 to the output terminals 20, 21 of a rectifier 19 in the power failure. In the power failure, the motor 6 acts as an electric generator because of inertia. At that time, an exciting current (if) is continuously supplied to maintain the excitation of the motor 6 to apply dynamic braking on the motor 6 forcibly rotated by inertial motion.

Inverter device for driving motor

Abstract: PURPOSE:To readily obtain desired braking force in a motor by firing only special element to supply DC current thereto when the generation of an AC motor is controlled. CONSTITUTION:When generated voltage signal set at a generating brake voltage setting potentiometer 60 is applied through a switch 61 closed upon request of braking to a voltage controlled amplifier 52, it is compared with the output voltage of a rectifier 21, and is erroneously amplified to become a current reference. This reference is compared with the output current of the rectifier 21 and is erroneously amplified by a current controlled amplifier 53 to obtain a phase control signal. This control signal determines the arcing angle of the gate of the thyristor to control the output voltage of the rectifier 21 to become proportional to the set position of the speed setting potentiometer 50. In this manner it can obtain desired braking force for dynamic braking of the motor.

System for automatic control of dynamic braking of independent transport facility

Abstract: A system for automatic control of dynamic braking of an independent transport facility comprises an exciting-current regulator of traction motors provided with rotational-speed transducers whose outputs are connected to the input of a traction-motor reactive e.m.f. limiter, and a voltage transducer whose output is coupled to the first input of a traction-motor exciting-current and brake-horse-power limiter formed with three interconnected rectifying bridges, the outputs of the two bridges being connected in accord and coupled to the output of the third bridge and to one input of a comparison unit, while the inputs thereof are connected to an exciting-current transducer and to a braking intensity setter, the second input of the comparison unit being connected through a diode to the traction-motor reactive e.m.f. limiter.

Control device for vehicle

Abstract: PURPOSE:To allow the vehicle to safely run down on a slope by continuing a dynamic braking operation in the vehicle even when a diesel engine is stopped. CONSTITUTION:A power switch 14 has a pair of common terminals, two sets of pairs of switching contactors N, E the terminals being connected to the input terminals at both ends of a main motor cooling blower motor 10, and the contactors N being connected to the output terminals at both ends of an auxiliary motor. The contactor E is connected to an intermediate tap 8' of a brake resistor for a main motor connected to the common terminal of the third change-over switch 7c and the switching contactor B of the third change-over switch 7c. Even when a diesel engine 1 is stopped by operating the power switch 14, the motor 10 receives a voltage generated by the main motor 4 of self-exciting state operating as a brake dynamic generator, can operate a blower for cooling the main motor. The diesel motor driven vehicle can continue the dynamic brake operation.

Brake controller for electric rolling stock

Abstract: PURPOSE:To prevent instantaneous excessive braking, by providing a timer means in connection with the cam shaft of a dynamic brake. CONSTITUTION:When a dynamic braking current IM becomes larger than a set current value IS, current relay 11 is energized and its contact 11b is shifted. At that time, a delaying timer 14 and a switch 15, which is triggered by the delay output of the timer to open a circuit at every step motion of advancement of a cam shaft, are connected between a comparator 6 and a controller 7 through the contact 11b. When a pattern current IP becomes larger than the dynamic braking current IM larger than the set current value IS, the output of the comparator 6 is conducted through the contact 11b of the relay 11 and delayed by the delaying timer 14. The delayed output is applied to a controller 7 through a switch 15. The controller 7 stops a pilot motor 8.

Controlling system for motor

Abstract: PURPOSE:To enable rapid braking by a method wherein a controlling power source for a DC motor is separated when abnormality is generated at the power source while a speed voltage component among the terminal voltage of the motor is detected, and the component is inverted and added to the terminal voltage. CONSTITUTION:A DC motor 2 is driven through a power amplifier 1. When abnormality is generated at a controlling power source for the motor 2, a switch 101 is turned OFF, and switches 11, 102 are turned ON. Thus, both end voltage of a motor current detecting resistor 12 is forwarded to a voltage-drop detecting circuit 13 of a motor series resistor RM, the output and the voltage of a motor terminal are given to a speed voltage component detecting circuit 14, and a speed voltage component of the difference is obtained by inverted polarity. The component is returned to the input side of the amplifier 1 through a resistor Rf, and terminal voltage having opposite polarity is applied to the motor 2. Thus, rapid braking which cannot be acquired by dynamic braking by direct short circuit can easily be conducted.

Braking system for electric motor vehicle

Abstract: PURPOSE:To obtain necessary braking force by flowing an electric current through the specific two phases of the three-phase winding of a squirrel-cage induction motor in a predetermined direction when a regenerative braking fails, thereby dynamically braking an electric motor vehicle. CONSTITUTION:If a regenerative braking fails due to the lack of a driven vehicle at a DC trolley wire side when the rotating energy of a squirrelcage induction motor 7a is regenerated through a PWM inverter 6 at the DC trolley wire side to allow the vehicle to regeneratively brake, the regenerative brake is stopped and reverse conducing thyristors 6U-6Z constructing the PWM inverter 6 are controlled to supply a direct current to the two phases of the motor 7a. Thus, the motor 7a is dynamically braked with the direct current. In this manner the dynamic braking can be performed without adding a specific main circuit configuration when the regenerative braking fails in the vehicle.

The sd50 locomotive

Abstract: The SD50 locomotive is the latest model in the Electro-Motive line of six-axle freight locomotives first introduced in 1952. The SD50 is a 3800/3500 horsepower heavy-duty freight locomotive with a number of new features, including the new model 645F engine, the D87 traction motor, a new model AR16 main alternator and the Super Series wheel slip control system. Ten SD50 prototype locomotives are currently in service on two U.S. railroads, four having gone into service in September, 1979, and six in December, 1980. The SD50 locomotive transmission system provides for permanent parallel motor connections with no requirements for either motor or generator transition and no need for field shunting or weakening. Experience to date indicates these locomotives can provide 33 percent improvement in adhesion as compared with previous model six-axle freight locomotives.