Abstract: An elevator system (1) comprises: a hoistway (4) extending between a plurality of landings (8, 9); at least one hoistway door (10, 11) allowing access to the hoistway (4); an elevator car (6), which is configured to move along the hoistway (4); at least one safety (16), which is attached to the elevator car (6) and configured to stop any movement of the elevator car (6) when activated; an electronic safety actuator (18), which is configured to activate and deactivate the at least one safety (16); and a door safety switch (20), which is configured to monitor the at least one hoistway door (10, 11) and which is connected with the electronic safety actuator in order to allow activating the at least one safety (16), if the door safety switch (20) detects that the at least one hoistway door (10, 11) is not closed.

Abstract: A braking system for waterborne propeller driven vessel which, upon activating a brake pedal or similar actuation device causes the vessel to almost immediately stop its forward movement. The system initiates a burst of highly amplified horsepower and torque, created by a controlled pulse of electrical power released from a bank of fully charged ultracapacitors. This pulse of electrical power is sent directly to AC induction-driven motors, causing oversized propellers to immediately rotate astern, thereby generating a reverse thrust in opposition to the vessel's forward movement sufficient to stop the vessel. The horsepower and torque produced by the braking system and operation of the present invention will also cause the oversize propellers to transmit this tremendous power into the water, without cavitation, to assist in stopping vessel movement.

Abstract: A method of controlling a digging operation of an industrial machine. The industrial machine includes a dipper, a hoist rope attached to the dipper, a hoist motor moving the hoist rope and the dipper, and a computer having a controller. The method includes monitoring a speed of the hoist motor, determining an acceleration rate of the hoist motor, comparing the acceleration rate of the hoist motor to a threshold reverse factor, determining an impact situation when the acceleration rate is less than the threshold reverse factor, and sending a reverse torque control command signal to the hoist motor.

Abstract: The screening device comprises a tubular element with an axis of rotation and rotatable in relation to a shaft device. It further comprises a screening body with one end secured to said tubular element and a free opposite end, which on rotation of said tubular element is adapted to move between a first position, in which the screening body is completely rolled up on said tubular element, and a second position, in which the screening body extends over said aperture in order to screen it. A drive unit for driving said tubular element comprises a motor connected to said tubular element and said shaft device such as to provide said rotation of said tubular element in relation to said shaft device. A control unit controls operation of said motor and comprises a printed circuit board with an electronic motion sensor. Said printed circuit board is located in a fixed position in relation to said axis of rotation of said tubular element and/or in relation to said shaft device.

Abstract: Regulating the speed of a two-phase switched reluctance machine (TPSRM) rotor includes selecting either a motoring mode or braking mode of operation for the TPSRM, regulating the rotor speed, when the motoring mode is selected, using a control signal cooperatively produced by a speed control feedback loop and a current control feedback loop; and regulating the rotor speed, when the braking mode is selected, using a control signal produced by the current control feedback loop without the cooperation of the speed control feedback loop. The speed control feedback loop uses an established speed control signal and a signal indicative of the rotor's speed to dynamically adjust a first parameter governing the control signal. The current control feedback loop uses an established current control signal and a signal indicative of the current flowing through a stator winding of the TPSRM to dynamically adjust a second parameter governing the control signal.

Abstract: A control device for a vehicle includes: a charge control portion that adjusts an upper limit of charging power to a battery to prevent a negative electrode potential of the battery from dropping to a lithium reference potential, based on a charge/discharge history of the battery; a braking control portion that detects a sharing ratio between hydraulic braking force by a braking device and regenerative braking force for desired braking force according to a brake pedal depression amount so that a motor generator generates a regenerative braking force within a range of the adjusted upper limit of charging power; and a setting portion that variably sets, according to the hydraulic response rate detected by the detection portion, a degree of limitation of the upper limit when restricting charging current to the battery by restricting the upper limit.

Abstract: A system for detecting a backspin condition of a motor in an electrical submersible pump is described herein. The system comprises a variable speed drive for powering the motor via a power cable; and a controller, the controller having a memory, a computer processor, and a computer program product stored on the memory and executable by the processor. The computer program product comprises the instructions of: monitoring an input current or impedance on the power cable to determine changes in motor current impedance, comparing changes in the motor current impedance to a historical threshold value for backspin events to determine whether the motor is backspinning; impeding operable power to the motor when it is determined the motor is backspinning; supplying a low AC voltage to the motor after it is determined the motor is backspinning; and determining whether or not the motor has stopped backspinning by monitoring the low AC voltage.

Abstract: A door operator for controlling operation of a door, the door operator having a motor to open the door against a spring force, the door operator further comprising a door position sensor for transmitting a signal indicative of door position; and among other things, calculates a door moment of inertia based on a net torque and the time for the door to reach a predetermined angle from the closed position. Also provided is a door operator that compares door speed to a desired door speed based on a door speed-position profile and generates a door speed error signal and minimizes the door speed error signal by adjusting the braking load resulting from charging a chargeable battery using the motor as a generator.

Abstract: In order to enable in a motor system, in which a soft start of the motor has been implemented, the operation of the motor, wherein the power consumption is reduced, it is proposed to operate the driver circuit during a switch-on phase in order to carry out a soft start of the motor. In at least one embodiment, the driver circuit can be bypassed in a normal operational phase as a function of a load, by means of which the motor is operated.

Abstract: A motor control apparatus providing an exercise resistance and an auto-rewinding function mainly employs a microprocessor to operate with a current detection feedback loop and a motor rotation speed detection loop for precisely controlling a quick random operation of a motor such that an axle of the motor can quickly control a loss braking unit and a power driving unit based on the existence of an external force, and the motor can automatically switch to an electric generator output mode (for providing an exercise resistance) or an electric machine output mode (for providing the automatic rewinding function).

Abstract: A motor driving device includes a brake mode control section for starting, when a brake instruction for a motor, braking of the motor in a reverse brake mode and then switching the reverse brake mode to a short brake mode; a cycle start detection section for receiving a rotation signal and detecting a start of a cycle of the rotation signal for each cycle; and a counter for performing, when the start of the cycle of the rotation signal is detected by the cycle start detection section, a count operation from an initial value. In the motor driving device, the brake mode control section detects that a value of the counter exceeds a threshold and performs switching from the reverse brake mode to the short brake mode with a delay from the detection.

Abstract: A motor control apparatus providing an exercise resistance and an auto-rewinding function mainly employs a microprocessor to operate with a current detection feedback loop and a motor rotation speed detection loop for precisely controlling a quick random operation of a motor such that an axle of the motor can quickly control a loss braking unit and a power driving unit based on the existence of an external force, and the motor can automatically switch to an electric generator output mode (for providing an exercise resistance) or an electric machine output mode (for providing the automatic rewinding function).

Abstract: A control circuit operates a dual directional DC motor from an AC power source. A controller has first and second position indication inputs adapted to receive respective first and second position indications. The controller also has first and second direction outputs, which respectively energize one of two first relay coils having contacts outputting respective AC voltages responsive to the direction outputs. A full wave bridge rectifier receives the AC voltage and responsively outputs a DC voltage, which energizes a second relay coil. A contact thereof directs that voltage to two sets of first relay contacts, which are also responsive to the direction outputs, and which respectively provide a positive or negative DC voltage to the motor. Another second relay coil contact provides a braking action to the motor responsive to removal of the DC voltage from the rectifier output following removal of the AC voltage to the rectifier.

Abstract: The side wall (5) for an ink fountain of a printing machine has two plates (11, 14) fixed some distance apart and an intermediate plate (13) having a front edge (13a) in the shape of an arc of a circle. This intermediate plate (3) is mounted between the plates in such a way that it can be shifted and tilted. The front edge of this plate contacts the circumference of an ink fountain roller (6) via springs (18, 19) acting on the intermediate plate. The wall has a slideway (10) in which the plates (11, 14, 13) are mounted. The slideway has a reinforced region (12) on one of its sides which is proximate the ink fountain roller (6). The side wall (5) thus more effectively seals an ink fountain against leakage.

Abstract: A series motor with commutator is disclosed which is especially suited as universal motor for a braked power tool. The series motor comprises a switch for switching between a motor mode and a braking mode, wherein, in motor mode, at least one field winding is connected in series with an armature winding in a motor circuit, which is connected to an a.c. power source, and wherein, in braking mode, the at least one field winding and the armature winding form together a closed braking circuit disconnected from the power source. The secondary winding of a mains-operated transformer is connected within the braking circuit. This arrangement guarantees improved safety of the braking action.

Abstract: A three-phase reluctance motor includes, a stator having a plurality of magnetic poles around which coils corresponding to three phases are wound, a rotatable rotor having a plurality of convex poles opposed to the magnetic poles of the stator, a magnet provided on the rotor for magnetizing alternately the convex poles to N- and S-polarities in a circumferential direction, and a control circuit for magnetically exciting selectively only two of the three phases to the N- and S-polarities, respectively, and for sequentially switching two phases which are to be excited, to thereby rotate drive the rotor.

Abstract: A method is disclosed for selective alteration and control of door movement modes utilizing an apparatus that is primarily non-hydraulic and incorporated with a known mechanism which is functional independently from the apparatus in one mode of operation and which includes a piston for controlling door closing characteristics by selected fluid flow within the mechanism. The apparatus includes a motor driven lead screw having a linearly movable shuttle unit mounted thereon, the shuttle unit being positioned relative to the piston of the mechanism to accommodate nonattached contact with the piston to urge the piston, when the shuttle unit is moved, in a direction that will at least provide selective assistance with door opening in another mode of operation. Operation of the apparatus is controlled by programming of a related controller including non-volatile memory.

Abstract: An adjustable speed control for use on a children's ride-on vehicle, where the speed control includes a switch assembly interposed between the battery and the motor of the vehicle. The switch assembly is selectively operable to connect the battery to the motor in one of a number of speed configurations, including a first speed configuration and a second speed configuration. An actuator is connected to the switch assembly and manipulable by a user to allow the user to operate the switch assembly to select a particular speed configuration from among the number of speed configurations. In one embodiment, a diode is disposed in series between the motor and battery in one of the speed configurations to provide a relatively current independent voltage drop between the motor and the battery. In an alternative embodiment, a childproof cover is disposed proximal to the actuator.

Abstract: A control circuit provides, for connecting a motor to a d.c. voltage source (1), two half bridge (3, 7, 5, 9) each with a respective switch (3, 5) with controlled opening and closing; the first of the half bridge connects a pole of the excitation winding (13) to the source (1) and the second of the half bridge connects a pole of the armature (15) to the source (1). A control unit (11) controls the opening and closing of the two switches (3, 5) of the half bridge and the toggling of the reversing device as a function of the operating conditions of the motor. The control unit (11) is programmed in such a way that in the braking phase it toggles both of the controlled switches (3, 5) cyclically, simultaneously or independently, from an open condition to a closed condition and vice versa.

Abstract: This invention relates to a mechanism for controlling rotational direction of a direct current motor and a applying brake thereto and in particular to one including a cathode connected to a negative pole of a battery, an anode connected to a positive pole of the battery, a first directional electrode connected to a negative pole of a motor and normally contacting a brake conducting plate, a second directional electrode connected to a positive pole of the motor and normally contacting the brake conducting plate and a switch which cannot be pressed down before moved sidewards and will, when pressed, cause the first directional electrode to separate from said brake conducting plate on one hand but contact the cathode or anode on the other hand, and to cause the second directional electrode to separate from the brake conducting plate on one hand but contact the anode or cathode on the other hand and will, when released, cause the first directional electrode to contact the second directional electrode via the brak

Abstract: An inductive load drive circuit for driving an inductive load, such as a motor, and for preventing charging of a power source by the back electromotive force of an inductive load. The inductive load drive circuit uses a battery as the power source for supplying power to the load. A first switching mechanism can serially connect and disconnect the inductive load and the battery. The first switching mechanism is controlled so that it disconnects the inductive load from the battery when the inductive load is in a condition in which the inductive load is able to generate back electromotive force or when the inductive load will be shifted to such a condition. Moreover, a bypass circuit can be used to consume the energy of the back electromotive force of the inductive load. A second switching mechanism is serially connected to the bypass circuit, with the serial combination of the second switching mechanism and the bypass circuit being in parallel with the power source.

Abstract: A motor stopping apparatus detects a rotation frequency of a motor to which a load is attached, and applies break power in accordance with the rotation frequency to the motor until the motor is approximately stopped. The apparatus may be provided in a disk storage.

Abstract: A variable speed electric hoist includes an invertor unit for frequency-controlling the speed of rotation of a lifting motor, a brake on/off section for turning off a brake according to a command produced from the invertor unit while the invertor unit is supplying a three-phase AC current to the lifting motor. The electric hoist also includes an emergency brake turn-on section for detecting a condition that a command produced from the invertor unit is not stopped after a lifting/lowering command is stopped to thereby turn on the brake upon detection of the condition.

Abstract: A system for controlling a pulse-driven dc motor includes a pulsed grounding switch, an inductor connected between the pulsed grounding switch and the armature of the dc motor, and a tracking circuit connected across the inductor. The control system further includes a variable resistor that provides a series path through the inductor for dissipating generated armature current from the motor. In operation, the resistance provided by the variable resistor depends upon the counter emf generated by the motor and upon transient voltages induced across the inductor when the pulsed grounding switch is periodically opened and closed. More particularly, the variable resistor provides minimal resistance when the back emf of the motor is low and provides increasing resistance as the back emf of the motor increases.

Abstract: An electric circuit with limit-switch for limiting rotatable range of an output shaft of an electric drive unit disposed between an electric motor and a control device for supplying a drive current thereto, comprising a first snap action limit switch disposed on a first input terminal of the motor, and a second snap action limit switch disposed on a second input terminal of the motor, the limit switches having pivot points of movable contacts on a motor side, their normally-closed contacts being connected to an output side of the control device and their normally-open contacts being connected to a common connecting point, and the normally-closed contacts of the first limit switch is connected to the common connecting point through a diode in the direction allowing an electric current to flow from each of the normally-closed contacts toward the common connecting point, and further comprising a diode for allowing an electric current to flow in parallel to the second limit switch, bypassing between the normally-

Abstract: In a tape drive system, a dynamic brake control circuit provides dynamic braking for slowing and stopping an associated tape reel and motor system in the event of a power failure. Upon sensing a power failure, the electrical energy stored in a capacitor supplies electrical energy to enable the control circuit, which in turn supplies a controlled conductive path for the flow of a dynamic braking current due to the back electromotive force signal generated by the motor, to effect the controlled dynamic braking of the drive motor to a stop.

Abstract: In connection with a switch arrangement for circuit-making and circuit-breaking, as well as for controlling the speed of, electric machines it is proposed to provide a double-pole circuit-maker and circuit-breaker safety switch and to connect it in series with the motor connections in such a manner that in a first switching position of the double-pole safety switch the connection to mains is established while in the other switching position at least one motor field winding is short-circuited with the armature winding by an actuating element provided in common for the two partial change-over switches, by changing the polarity for instantaneous braking, there being provided a separate speed-setting selector switch which can be operated independently of the saftey switch and which is designed to permit presetting of a motor cut-out position which enables the motor to run out freely when the safety switch does not respond separately or when the device is not opened to cause the safety switch to respond.

Abstract: A brake apparatus for automatic doors including a speed pulse signal output device for providing speed pulse signals at a time interval inversely proportional to the door speed of an automatic door, a brake for slowing the door speed, a braking position detector for detecting braking position when the brake starts braking, a brake effect measurer for measuring the effect of the brake and a braking power controller for adjusting the braking power of the brake in accordance with the measured braking effect whereby the motion of the door is kept constant irrespective of the door weight and other conditions.

Abstract: A motor control device for a radio control system is disclosed. The motor control device is mounted on an object to be controlled so as to adjust a control range in each of forward, braking and backing of the object. The motor control device is provided with a variable reference signal source for generating a backing reference signal and a comparator for discriminating a region of control element on a transmitter side by comparing a braking-backing command signal generated from a drive control circuit with the backing reference signal. The control range can be adjusted by adjusting a level of the backing reference signal of the variable reference signal source.

Abstract: A child's battery-powered riding toy includes a floorboard with two spring-biased switches that must be closed by the child operator to place the vehicle in self-powered motion and can only be reached simultaneously of the child operator is safely aboard. The battery power supply is capable of providing high or low voltage to the motor drive, but a reversing switch is connected between the battery power supply and the motor drive, and it must be in its "forward" position to receive the high battery voltage. In its "reverse" position, the reversing switch separately connects the motor drive to only the low battery voltage. The spring-biased switch connected directly to the reversing switch has a dynamic braking load connected to it to be placed across the motor drive when the reversing switch is in its "forward" condition and the latter spring-biased switch is allowed to be under the control of its biasing spring.

Abstract: An anti-plug reversing circuit for use with a variable speed D.C. motor which provides safe and fast motor reversing with dynamic braking. The circuit, by sensing counter-EMF, prevents the premature application of a voltage of opposite (reversing) polarity until the motor armature has come to a full stop. The circuit advantageously utilizes a three-wire control input, is low cost, easily manufactured and applicable for use with low cost D.C. motors.

Abstract: A control circuit for regulating the application and release of brake force in an electric brake. A pulse width modulator presents an output signal of regulatable duty cycle to power drivers connected to the electric motors of the brake. A control circuit regulates the direction of current flow through the motors to achieve either brake application or brake release. The output of the pulse width modulator is set by the position of the brake pedal or by a signal which is a function of the correlation betwen brake torque and the position of the brake pedal, whichever is larger.

Abstract: In an electrical tool having a clutch for adjusting rotational torque of the driven shaft, a limit switch of double-throw type is used for detecting the state of the clutch, and a capacitor is arranged to be charged via the limit switch. In one embodiment of the instant invention, the capacitor is normally discharged and is charged when the clutch assumes a disengaged state, thereby producing a trigger pulse used for making a short circuit for the motor only when the capacitor is not fully charged. In another embodiment, the capacitor is normally charged, and is discharged when the clutch assumes a disengaged state, thereby producing a trigger pulse used for making a short circuit for the motor. With this arrangement a switching circuit provided for making the short circuit for the motor is effectively prevented from making the short circuit when a power switch is turned on irrespective of the state of the clutch.

Abstract: An electric actuator having an electric motor operable to control the output force generated by a spring system of the actuator on an output member of the actuator; measuring means responsive to a characteristic of the spring system which is indicative of the value of the output force; and an electrical circuit by which operation of the electric motor can be initiated and can be terminated when the measuring means detects the characteristic as being indicative of the output force of a required value.

Abstract: Disclosed is an automatic door actuator which comprises arithmetic unit for calculating a weight of a door, a distance of movement of the door and braking points of the door through learn control of door actuation which is effected once every time a power supply switch is turned on and irrespective of the on-off condition of a normal door actuation start switch; first memory for storing results of calculation by the arithmetic unit; second memory for previously storing various phase angles for starting operation, for deceleration braking operation and for predetermined low velocity control, corresponding to various weights of the door; whereby the control unit is responsive to the first memory to read out from the second memory the phase angles for starting operation, for deceleration braking operation and for predetermined low velocity control corresponding to the actual weight of the door determined in the learn control to thereby supply a trigger signal to semiconductor controlled rectifying elements in ac

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.

Abstract: A reversible electric drive with bidirectional back-current brakes fed by a rectifier supplied from a pair of A.C. power lines for a D.C. motor having two directions of rotation and two poles, comprises a control rectifier bridge for each direction of rotation, each bridge having two branches each containing a diode which is common to both bridges, a shunt resistor for each direction of rotation which is identical with a braking resistor for each other direction of rotation connected in series with the motor for each bridge, each bridge having two other branches each containing a rectifier thyristor with cathodes of each rectifier thyristor connected to a common point. The common point of each bridge is connected to one of the poles of the motor with a control thyristor connected to each common point in series with each respective shunt resistor of each bridge and connected to each other by a connecting point.

Abstract: An electronic circuit designed to control entirely by electronic means the change from traction mode to braking mode and vice-versa of a separately excited DC machine and the forward and reverse operation of the motor as well as rheostatic braking. The chopper includes two main thyristors (T1) and (T2) and a single switch-off thyristor (T3) for the two main thyristors. The direction of current flow through the separate excitation winding (J) is determined by four thyristors (T5) to (T8).Application to railway traction.

Abstract: An emergency brake control system for hoists including means for generating a first electrical signal indicating the direction of travel of a conveyance, means for generating a second signal indicating the presence or absence of an emergency situation and control means responsive to the first and second signals for immediately applying the emergency brake when the conveyance is descending and an emergency exists and delaying application of the emergency brake only after the conveyance has come to a complete stop when the conveyance is ascending and an emergency exists. Overriding safety features may also be employed to provide immediate application of the emergency brake regardless of the direction of travel of the conveyance of certain emergencies, such as over travel of the conveyance, exist.

Abstract: A windshield wiper system having an electric motor for driving windshield wipers through repeating wiper cycles by reversing the direction of rotation of the motor through a reversing switch comprising a pair of relays which control the polarity of current applied to the motor. A limit switch is mechanically coupled to the motor for detecting the end positions of the motor and for providing signals indicative thereof. First and second time delay circuits each have an output respectively coupled to one of the relays, and each delay circuit has a pair of inputs coupled to the limit switch. Each delay circuit is activated to provide a delayed output to its relay by a respective end position signal which immediately deactivates the other delay circuit.

Abstract: In the disclosed device, forward and reverse rotation of a motor is used to wind and rewind a camera. A first semi-conductor switching element becomes conductive during winding and a second semi-conductor switching element becomes conductive during rewinding, the switching elements being connected in series across a power source. A selector switch has its fixed terminals connected to opposite poles of the power source. The motor is connected between the armature of the selector switch and the point between the switching elements. Driving circuits operate the switches so that the motor is driven in one direction when the selector switch is in one position and the reverse direction when the selector switch is in the other position and arranged to brake the motor after rewinding has stopped.

Abstract: In a D.C. motor in which signals generated by an angular position transmitter control the commutation of the current flowing through the stator winding via a selection circuit containing Exclusive OR gates by means of which the polarity of the signals generated by the angular position transmitters can be reversed for the reversal of the direction of rotation, operating modes of "Operation" and "Braking" can be specified with only one command input for the Exclusive OR gates using an additional Exclusive OR gate.

Abstract: A rotary tap changer or switch is rotated by a motor to a plurality of contactor positions by a control system having a cam that rotates to activate limit switches respectively corresponding to contactor positions. The activation of the limit switches causes operation of a relay which, after a selected time delay, operates to discharge a capacitor across the motor to apply dynamic braking and stop the motor. When starting the motor to rotate the tap changer, energization is applied through the limit switches to select rotation in a forward or reverse direction determined with some modification by the shortest distance of rotation to the new selected position.

Abstract: A projection screen apparatus includes an elongate roller, a flexible screen which is wound on the roller when it is in a closed position and unwound from the roller when it is in an exposed position, an electric drive motor connected to the roller for rotating the roller to move the screen between exposed and closed positions, a first switch for actuating the drive motor to move the screen toward a closed position, and a second switch for stopping the drive motor and the roller when the screen is in a fully closed position. A free marginal end portion of the screen engages a lever which moves the second switch to an inoperative position to interrupt the electric circuit leading to the drive motor.

Abstract: A control circuit for an electrically driven vehicle which employs a separately excited motor. The armature is connected in series with a current control between two supply rails. The field winding is likewise connected between the rails, but has associated with it switch means for reversing the connection of the field winding. A diode arrangement is provided for recirculating current when the field circuit is interrupted and for establishing a recirculating path through the vehicle battery when the field connections are reversed, by the switch means.

Abstract: In the computer field tape handlers for magnetic tape are widely used. The magnetic tape is moved by a capstan driven by a high power low inertia motor since it is necessary to rapidly accelerate and decelerate the tape in both forward and reverse directions. A high power motor is provided with a command controlled direct current. The motor direction is determined by the selection of one of two pairs of solid state switches. Only one current control circuit is used. Transients are minimized by permitting only one pair of switches to be closed at any time and by switching when the controlled current is at a low value.

Abstract: In an electric propulsion control system for self-propelled traction vehicles having reversible, variable speed tractiOn motors, wherein the operation of a direction selector means overrides the normal speed controlling means and initiates a dynamic retardation operating mode so as automatically to decrease the speed of the traction motors, and means responsive to the motors subsequently decelerating to a predetermined relatively slow speed effects a reversal of motor energization so as to reverse the direction of the vehicle.

Abstract: In a universal motor particularly adapted for operating a compact winch, triggering the dynamic braking, as may be required in an overhauling load condition by applying a pulse of current through the field winding as to produce a magnetic field to assuredly cause the armature to start generating a current which is directed through the field winding and load resistance, the pulse of current being supplied from a condenser connected in shunt with the field winding or the condenser may be connected in series with the field winding and in shunt with the switch by which the field winding is connected to the supply line; a time delayed switching shorting the dynamic braking resistance to increase the generated current and produce renewed or a second dynamic braking effect to reduce the speed of the motor sufficiently to allow the worm and worm gear speed reduction to lock against further rotation under influence of the winch drum; and low speed braking being increased to produce stopping of the motor and winch drum