Japan Servo Co.,ltd.

Hitoshi Ando

Eiji Kuroda

Yasushi Niwa

Kazufumi Yamashita

Eiji Kubozuka

Kentaro Yamane

Atsuo Nakayama

Naoko Toida

The stepping motor controller comprising an excitation signal generator, a switching circuit, a PWM constant current control circuit and a current sensor further comprises a motor detector circuit that transmits a control signal for generating a constant current for a predetermined time for detecting the motor, a constant current generator that receives the control signal and generates the constant current to be supplied to the winding, a reference voltage generator that generates a reference voltage, a voltage comparator circuit that compares the reference voltage with a voltage drop at the winding, and a current value setting signal generator circuit that transforms an output of the voltage comparator circuit into a current value setting signal for the PWM constant current control circuit. An output of the current value setting signal generator circuit is connected to a current value setting terminal of the PWM constant current control circuit.

Stepping motor controller

An automatic ice maker for use in freezing compartments of the refrigerators. A planar stop arm is used as an ice cube detecting device for detecting a sufficient ice cubes stored in a bin arranged below a tray for making ice cubes. The stop arm can be swung between the bin for storing therein the ice cubes and the tray in order prevent the ice cubes stored in the bin from being molten by a head radiation from a heater provided on the tray.

Automatic ice maker

An automatic ice making apparatus having a sensor which can detect continuously a temperature of an ice making tray is used as a temperature sensor. The temperature and a temperature variation rate of the ice making tray are detected by an electronic control circuit having a function corresponding to an A/D converter and a microprocessor or the like to determine a freezing state of water. Further, a thermistor is used as the temperature sensor, and by and A/D converter including a microprocessor a water level in the ice making tray is detected and a solenoid valve for determining an amount of supply water is controlled so as to suppress the water amount variation due to a water pressure change or the like.

Automatic ice making apparatus

A driving circuit of a stepping motor comprises an excitation control circuit connected to windings of a stepping motor, a driver circuit consisting of power switching transistors at a positive terminal side of a power source and of power switching transistors at a negative terminal side of the power source for controlling the excitation control circuit, a Zener diode inserted between the power source and a power input terminal of the driver circuit, and Zener diodes inserted between output terminals of the driver circuit and control signal input terminals of the power switching transistors at the positive terminal side of the power source, respectively. The Zener voltage of the Zener diode for the power switching transistor is determined to a value not less than a voltage difference between the voltage of the power source and the maximum rated voltage of the driver circuit.

Growing community of inventors

Gunma, Japan

Hitoshi Ando