Showing papers on "Dynamic braking published in 1983"

Electrical braking control for DC motors

Abstract: An electrical braking control circuit for use in a control system for a direct current traction motor which may be employed, for example, to propel an electrically driven vehicle. The electrical braking controller of the invention initiates electrical braking in a plug mode of braking and then, when conditions are suitable for regenerative braking, causes a transition to regenerative braking, followed by return to a plug mode of braking whenever regenerative braking can no longer be efficiently achieved, all of which is carried out smoothly and efficiently without unduly wasting regenerative power.

All terrain vehicle toy with dynamic braking

Abstract: A childs wheeled riding toy of the three wheeled type having a front steerable wheel and a pair of rear motor driven wheels in which the child sits astride of the toy with his feet resting on opposed foot rest positions of the toy is disclosed having a pair of direct current motors, gear reduction coupled in driving relation to respective rear toy wheels and a pair of like storage batteries for powering the motors. A control circuit for selectively energizing the motors includes a switching arrangement for connecting the batteries in series and to the motors for high speed toy operation, and in parallel and to the motors for low speed operation. A second switching arrangement for disconnecting the motors from the batteries and for connecting the motors to a resistive load for dynamic braking is also included. Still further, a foot actuable dead man switching arrangement which is normally biased to an open circuit condition to preclude application of battery power to the motors is accessible to the child and operable to a closed circuit condition for enabling the motor drive arrangement.

Electronic Motor Braking

Abstract: Electronic motor brakes (EMB's) can be applied to both new and existing machines to provide a rapid nonmechanical adjustable braking profile. They can also be used to supplement the braking torque of existing brake motors, forming a complete sequential braking system for demanding applications. The EMB stops without friction or wear. It also provides for an adjustable soft stop and can be mounted remotely from the motor. The new brake stops an ac induction motor by applying dc to the motor stator, thus providing braking torque within the ac motor. The EMB has two adjustments-braking current and braking time-which allow the selection of almost any braking profile. A positive lockout prevents the motor from being restarted during the braking phase. The typical electronic braking current is two to three times rated full-load current of the motor. Thus the heating effects upon the motor caused by the application of dc during the stopping function are minimal, particularly when compared to other electronic braking techniques such as plugging. The EMB becomes a part of the industry's only complete sequential braking package when combined with a motor-mounted friction disk brake which is spring-set and electrically releases to stop the load in the event of power failure and to provide a holding function. Together, the two types of brakes can offer an adjustable soft-stop profile with secure holding, as well as the ability to stop or slow down high inertia loads, yet stop them in the event of a power failure.

Primary and secondary dynamic braking system

Abstract: A dynamic braking system is provided for electrically driven wheelchairs to slow the wheelchairs to a stop without needing to use a mechanical brake. A primary switch arrangement is provided for connecting resistors across the right and left wheelchair motors automatically when the switch control is in its off position, either because of purposely positioning the control by the patient or as a consequence of power failure. In addition, a secondary switching system is automatically actuated in response to the primary switching system being moved to its off position to cross connect or short circuit the terminals of the right and left motors to each other only after a given period of time to provide a secondary braking action to the motors and bring the wheelchair to a complete rest.

Turbine engine system

Abstract: A gas turbine engine system (10) for powering a ground vehicle such as an automobile, truck, bus or other vehicle, is provided with a continuously-variable transmission (18) in the form of a declutchable toroidal traction drive, whose two drive lobes (48,50) are coupled through reduction gearing (40,42 and 44,46) respectively to the shaft (30) of a gas generator section (12) of the engine system (10) and to the output shaft (16) of a free power turbine (14) driven by the high-energy combustion gases of the gas generator section (12). A clutch (58) is provided for selectively engaging the toroidal traction drive (18), by axially moving one of its lobes (48,50) towards the other, for bidirectional mechanical power transfer between the free power turbine (14) and the gas generator (12). Power may be transferred from the free power turbine (14) to the gas generator section (12) to slow rotation of the powe turbine and provide dynamic braking and also during vehicle transmission speed shifts. Power may be transferred from the gas generator section (12) to the power turbine (14) during part-load engine operation to improve the efficiency of operation of the gas generator section in that mode.

Encoder controlled apparatus for dynamic braking

Abstract: A rapidly-spinning motor-driven disc is quickly brought to a halt by utilizing the motor in a controlled current dynamic feedback mode. An electrical signal is provided to cut off the motor braking current when the rotating motor shaft reaches substantially zero velocity, thereby avoiding any residual rotation of the disc. As the disc slows at a constant deceleration rate, the apparatus measures the relative time durations of two consecutive pulses which represent equal displacement arcs on the disc. From these data the time at which zero velocity will be achieved is computed, and the motor current cutoff signal is generated at the proper instant.

Drive system for automatic clothes washing machine

Abstract: A clothes washing machine wherein the clothes receiving basket is driven through a speed reduction transmission by an electronically commutated motor operable unidirectionally in one mode for rotating the basket to effect a spin extraction cycle, and in a second mode motor rotation is cyclically reversed to cause oscillation of the basket during the washing operation. The speed reduction transmission is adapted to counteract the inertia of the basket generated by the high speed extraction cycle to provide a secondary braking action of the basket which supplements the dynamic braking capacity of the motor.

Controller for electric rolling stock and controlling method thereof

Abstract: PURPOSE:To reduce the abrasion of a brake shoe by controlling regenerative braking and jointly using regenerative braking control and dynamic braking control continuously and reversibly in response to stringing voltage. CONSTITUTION:When power travelling control, a thyristor 9 is at ON, and the slip frequency of induction motors 6 is controlled by means of a three-phase inverter section 4. When a brake command is emitted, the ignition control signals of the thyristor 9 are released, and regenerated at the contact wire side by the loop of the three-phase inverter section 4, a reactor 2, a diode 10 and a high-speed breaker 1. When the voltage of a capacitor 3 reaches set value at that time, a switching element 11 is ignited, and regenerative currents are shunted to a resistor 12. The switching element 11 is arc-extinguished at a point of time when the one sixth cycle period of the output frequency of the three-phase inverter 4 is completed. When the voltage of the capacitor 3 drops, control is shifted to regenerative braking control again.

Zero-sequence dynamic braking and parameter determination

Abstract: The performance of AC and DC zero-sequence dynamic braking is compared with conventional DC dynamic braking. In addition, a method of determining the zero-sequence parameters and parameter variations of a 3-phase squirrel-cage induction motor, having a current-displacement rotor, is described. It is indicated how these parameters may be used to help determine the type of dynamic braking system to be employed in a practical situation.

Dynamics and Handling Characteristics of Single Track Vehicles During Braking and Acceleration

Abstract: This paper presents mathematical models (vehicle model and tire model) to study the dynamic behavior and vehicle handling characteristics of single track vehicles during braking and acceleration.

Controller for motor

Abstract: PURPOSE:To effectively utilize energy stored in a smoothing capacitor by utilizing the energy as that for performing dynamic braking at a motor. CONSTITUTION:When a motor 5 is decelerated with speed setting means 9 in case the motor 5 is rotated, the output frequency of a power inverter 4 varies smoothly since a softening circuit 10 is provided. Thus, regenerative brake is applied, and the terminal voltage of a smoothing capacitor 3 will rise. When the voltage of the capacitor 3 becomes the prescribed value, overvoltage detecting means 16 produces a signal. In this manner, a base signal from a base signal amplifier 14 to a specific element forming a power inverter 4 is stopped. At this time the motor 5 is dynamically braked by the energy from the capacitor 3.

Brake device of unreel stand

Abstract: PURPOSE:To correctly control sheet tension, by utilizing dynamic braking of DC motors rotated through sheet rolls. CONSTITUTION:Current control circuits 10A-10C, for controlling DC motors 9A-9C, rotated by rotary motion of sheet rolls 1A-1C, auxiliary power source 11, for flowing an auxiliary current to the DC motors 9A-9C, and an arithmetic unit 12, generating a reference signal showing a value of required armature current, flowing in the DC motors for applying brake force to obtain prescribed tension in accordance with a winding diameter of the sheet rolls 1A-1C, are equipped. In this way, tension of a sheet can be surely controlled without causing the necessity for utilizing mechanical friction.

Regenerative and dynamic braking system for electric motor vehicle

Abstract: PURPOSE:To obtain stable braking force by connecting a parallel circuit of a dynamic braking resistor and a bypass thyristor in series with a chopper and controlling the current flow rate of the thyristor in response to the power absorbing capacity of a power source. CONSTITUTION:A parallel connecting circuit of a dynamic braking resistor 32 and a bypass thyristor 34 is connected in series with a chopper 26. When the power absorbing capacity of a power source is lowered at the regeneratively braking time, the current flow rate of a chopper 26 is controlled in response to the power absorbing capacity of the power source, the current flow rate of the thyristor 34 is controlled, thereby regeneratively and dynamic braking and controlling the motor current constantly. In this manner, an automatic and stable dynamic braking is obtained in response to the power absorbing capacity of the power source.

Gyroscope wheel dynamic braking and sequence inhibit circuit

Abstract: An inertial measuring unit gyroscope wheel dynamic braking and sequence inhibiting circuit is disclosed. The circuit comprises a first counter for counting a specified time interval and digital logic circuitry for applying an in-phase signal to the phases of a multiphase electric induction motor driving a gyroscope wheel during the time interval, for example, a vertical gyroscope motor wheel. By placing in-phase signals on the inputs of a multiphase electric induction motor, the motor is brought completely to rest in a short time by dynamic braking. In a preferred embodiment, a second counter counts a second specified time interval after the first time interval has terminated, during which second time interval a second electric induction motor is dynamically braked, for example, an azimuth gyroscope wheel motor. During the time period when the motors are braking, a signal is fed back to an automatic sequencing circuit to inhibit further sequencing of the inertial measuring unit.