Abstract: A method for controlling a transformer includes specifying, in one or more control devices, an initial operating limit (e.g. an initial current limit or an initial temperature limit) for one or more windings of the transformer. Further, the method includes monitoring, via one or more sensors, at least one electrical condition of the one or more windings of the transformer (e.g. current or voltage). The method also includes receiving, by the one or more control devices, a signal indicative of the at least one electrical condition of the one or more windings of the transformer. As such, the method further includes adjusting, by the one or more control devices, the initial operating limit based at least in part on the at least one electrical condition of the one or more windings of the transformer.

Abstract: A crane having progressive function control preferably includes the crane, an electronic control device, a load sensor, a boom angle sensor, a boom length sensor, and a steering angle sensor. The load sensor measures a load on the crane boom. The boom angle sensor measures an angle of the crane boom. The boom length sensor measures a length of the crane boom. The steering angle sensor measures an angle of the rear wheel. The load sensor, boom angle sensor, boom length sensor and steering angle sensor are read by the electronic control device. The electronic control device receives inputs from a drive joy stick, a boom angle joy stick and a boom extension joy stick. The electronic control device includes a drive reduction algorithm and a boom reduction algorithm. The algorithms are used to retard inputs from the drive joy stick, boom angle joy stick and boom extension joy stick.

Abstract: A motor driving apparatus for driving and braking a motor equipped with a brake comprises a motor/brake driving DC power supply which is used both as a motor driving power supply and as a brake driving power supply, wherein when the motor/brake driving DC power supply is being used as the motor driving power supply, a voltage conversion circuit via which a voltage supplied from the motor/brake driving DC power supply is applied to the brake feedback-controls the voltage applied to the brake. This configuration serves to reduce the loss (due to temperature rise) in the brake coil of the motor being driven to move a robot arm.

Abstract: A controller includes a power source unit, a drive circuit, and a state control circuit. The drive circuit is coupled to the power source unit, and includes a drive coil and a switching transistor unit. The switching transistor unit is operable in one of a circuit-making state for making an electrical circuit between the drive coil and the power source unit so as to enable the drive coil to drive rotation of a rotor of a brushless direct current motor, and a circuit-breaking state for breaking the electrical circuit between the drive coil and the power source unit. The state control circuit is coupled to the power source unit, and includes a pulse width modulator, a sensing coil, and a control transistor coupled electrically in series. The state control circuit controls operation of the switching transistor unit according to magnetic position of the rotor relative to the sensing coil.

Abstract: A drive system for washing machines, electric vehicles or the like has its winding switched to effect speed change and an asynchronous motor operated by a frequency converter where there are more than two grooves per pole and phase with respect to the motor and the number of grooves of the rotor exceeds the number of grooves of the stator whose sheet pack is welded along the back. The windings are formed as short-pitched chord half-hole windings.

Abstract: A device for controlling an AC motor for a fork lift truck comprises a detector to detect direction of rotation of an AC motor. The direction of rotation thus detected is compared with a desired direction of rotation of the AC motor, and the AC motor is controlled such that the AC motor operates in a power running mode when the actual direction of rotation of the AC motor is equal to the desired direction of rotation of the AC motor, but it operates in regenerative braking mode when said actual direction of rotation of the AC motor fails to be equal to the desired direction of rotation of the AC motor. The desired direction of rotation of the AC motor may be set manually by an operator or a driver of a vehicle drien by the AC motor.

Abstract: An AC elevator control system has a converter for converting a three-phase AC power to a direct current, an inverter for inverting the direct current to a three-phase AC power with a variable voltage at a variable frequency, and a three-phase induction motor for receiving the last-mentioned AC power to operate an elevator car connected to a counterweight through a traction rope trained over a sheave. A battery connected across the DC side of the inverter is enabled upon the occurrence of a power failure or a fault. A command emergency frequency generator responds to the occurrence of an emergency such as a power failure to deliver to the inverter a low frequency emergency frequency as determined by the relationship between a difference in weight between the elevator car and the counterweight and various losses of a motor driving system so as to cause the induction motor not to generate regenerative power.

Abstract: An SCR bridge of an elevator speed control apparatus is connected between an induction motor 5 and two (R, S) of the three-phase power supply terminals. Two diagonally opposite legs of the bridge comprise single SCR's 25, 26, and the other two legs each comprise a pair of parallel, reverse polarity SCR's 21, 22; 23, 24. The third power supply terminal is connected directly to the motor through a single switch contact 8. By appropriately controlling the switch contact and the SCR.varies.s in accordance with the difference between the actual and commanded elevator speeds, the bridge can be configured to implement three phase running during acceleration and constant speed modes, single phase running during a transitional slow down mode, and D.C. braking during a deceleration mode.

Abstract: An electronic system is disclosed for controlling both the ascendant and the descendant speed in vertical machines such as cranes, elevators, etc., in which it is required to lift different loads in a regulated and self-controlled manner, laying aside the traditional mechanical and/or pneumatic control systems. Such control is achieved by virtue of the voltages included in the secondary of the motors of the wound rotor type used in such machines to lift or to bring down different loads, which may vary within a wide range from practically the vacuum to an overload, being possible by such control to select and to maintain both the ascendant and the descendant speed of the load.

Abstract: A bidirectional triode thyristor is connected to an R phase of a three-phase induction motor through an up contact set and to its S phase through a down contact set. A full-wave rectifier bridge including four diodes is connected across the R and S phases to be enabled during deceleration of the motor. The thyristor is controlled by an R-to-S phase firing circuit responsive to a command acceleration signal during acceleration of the motor and a difference signal between a command deceleration signal and an actual speed signal for the motor during deceleration of the motor.