Title:
METHOD FOR JUDGING POSITION OF IRON CORE OF SOLENOID
Document Type and Number:
Japanese Patent JPH0313802
Kind Code:
A
Abstract:
PURPOSE:To detect the positions of iron cores without using a special detector by detecting the ratio between AC voltages which are applied to two driving coils. CONSTITUTION:The linking point of a pair of driving coils 4 and 5 is grounded through a resistor R. When transistors Tr1 and Tr4 or Tr2 and Tr3 are conducted, a DC power source +B for excitation is applied to the driving coils 4 and 5 in the reverse direction, and iron cores are driven. Capacitors C1 and C2 are provided in parallel with the driving coils 4 and 5. An AC power source Vx is applied to the central point between the capacitors C1 and C2. The difference between the AC voltages generated at a point A and a point B is obtained with a differential amplifier circuit 15. In this way, an AC bridge is formed, and the difference between the impedances of the driving coils 4 and 5 is obtained. Since the impedances of the driving coils 4 and 5 are changed in response to the positions of the iron cores, the positions of the iron cores can be obtained in this way.
Inventors:
KIN TOJI
MIYAZAWA KAZUHIRO
MIYAZAWA KAZUHIRO
Application Number:
JP14828489A
Publication Date:
January 22, 1991
Filing Date:
June 13, 1989
Export Citation:
Assignee:
FURUKAWA ELECTRIC CO LTD
International Classes:
G01B7/00; (IPC1-7): G01B7/00
Attorney, Agent or Firm:
Koji Nagato
Next Patent: JPH0313803