A device for inrush current prevention and dynamic braking in a motor having a plurality of power inputting terminals, comprises a diode rectifying unit rectifying power supplied from an AC power supplying unit; a capacitor smoothing the power rectified by the diode rectifying unit; a resistor disposed between the AC power supplying unit and the capacitor, being connected to the capacitor; an inverter connected to terminals of the capacitor and the power inputting terminals of the motor, inverting the power from the capacitor into an AC power having multiple phases and supplying the AC power having multiple phases to the motor; a dynamic braking circuit short-circuiting the power input terminals of the motor; and a relaying unit including a first node connecting the dynamic braking circuit to the resistor and a second node connecting the diode rectifying unit to the capacitor in parallel.

Device for inrush current prevention and dynamic braking in a motor

PROBLEM TO BE SOLVED: To make the force of an electric motor required for opening a valve smaller than the closing force of the valve by making a valve shaft separable from a motor shaft in closing of the valve. SOLUTION: In opening operation of a valve, a rotor 32 including a magnet 31 is rotated stepwise in the valve opening direction by the pulse voltage transmitted from a control unit to a terminal 29. At this time, the transmission pulse number is conformed to the step number, and a precise open loop control can be performed. This step-like rotation is converted to a linear motion by the screw part 32a of a rotor 32 and the screw part 33a of a motor shaft 33, and the motor shaft is moved in the valve opening direction. The movement of the motor shaft 33 is assisted by the force of a spring B44. Since the force of a spring A12 is added the moment the motor shaft 33 is further moved to bring a joint 43 into contact with a spring holder A10, the force necessary for moving the motor corresponds to the difference between both the springs. COPYRIGHT: (C)2000,JPO

Motor-operated control valve device

PURPOSE:To avoid the starting-impossible state of a starter by automatically suspending the supply of electricity when the battery voltage lowers below and allowable range because of the continuation of putting-ON state of a headlamp or a small lamp during the engine stop or the use of cassette deck, etc. CONSTITUTION:The first opening/closing element 4 in always opened state is interposed between a bettery 1 and the load such as a headlamp, small lamp and a cassette deck, and the second opening/closing element 4a in always opened state is interposed between the battery 1 and the ACC contact point of an ignition switch 2. A voltage level judging means 3 is connected with the ACC contact point, and it is judged if the battery voltage lowers below a prescribed value or not. When it is judged that the battery voltage lowers below the prescribed value, the first and second opening/closing elements 4 and 4a are opened to cut off the electric conduction to the load, and an alarm means 5 is operated to perform alarm of the reduction of the voltage level.

Automatic electric power switch for vehicle

PROBLEM TO BE SOLVED: To provide an electric power conversion system with a simple configuration, capable of protecting an electric power conversion system body from regenerative power from a load.SOLUTION: The electric power conversion system comprises: an electric power conversion system body (an inverter) that drives a load with an input power voltage; and a brake circuit that protects the electric power conversion system body from an overvoltage applied to the electric power conversion system body. The brake circuit includes a Zener diode that conducts when a voltage applied to the electric power conversion system body exceeds a predetermined value to suppress the voltage applied to the electric power conversion system body.

Electric power conversion system

PURPOSE: To reduce the number of parts having larger current capacity and to lower the cost of a controller and compact it by adding a function of dynamic braking on the abnormality of load to a discharge circuit used for inhibiting the rise of intermediate voltage. CONSTITUTION: When a protective circuit 20 drives each transistor T 1 ∼T 6 for an inverter circuit 6 while the overcurrents of a servomotor 7 are detected by an overcurrent detector 21, several transistor T 1 ∼T 6 is interrupted while a main switch 1 is opened. The main switch 1 is opened while a contact 14 is brought to an ON state, a switching transistor 9 is turned ON, and the charging voltage of a capacitor 4 lowers. When the charging voltage of the capacitor 4 is lower than generated voltage by the servomotor 7, the generated voltage of the servomotor 7 charges the capacitor 4 through diodes D 1 ∼D 6 , thus generating regenerative action in the servomotor 7. COPYRIGHT: (C)1987,JPO&Japio

Emergency dynamic braking system of servomotor

PURPOSE:To switch a speed control to a current control or vice versa shocklessly by eliminating the abrupt change in the command input of a current regulator immediately before and after switching when switching the command input of the regulator. CONSTITUTION:A subtracting circuit 1 has a subtractor 11 and a polarity inverter 12 to form Y-X, X-Y from the output X of a speed regulator 7 and the output Y of a current command generator 6 and to input them to switches 21, 22. The switch 21 opens or closes the output Y-X of the subtractor 11, and the switch 22 opens or closes the output X=Y of the inverter 12. Calculators 31, 32 delay the outputs Y-X, X-Y to attenuate them. An adder 41 adds the signal X to the output Y-X of the calculator 31. An adder 42 adds the signal Y to the output X-Y of the calculator 32. A selector 5 selects either one of the adders 41, 42 and outputs the input Z of the regulator 8.

Tamura Yasuharu

Papers

Emergency dynamic braking system of servomotor

Signal switching circuit