Title:
DEVICE FOR PROTECTING PHASE SEQUENCE WIRING
Document Type and Number:
Japanese Patent JPH07255124
Kind Code:
A
Abstract:
PURPOSE: To determine correct phase sequence easily by an arrangement wherein an impedance connects two resistors of equivalent system and one capacitor in Y and the difference of output from analog comparison networks connected, in row, with one resistor is monitored. CONSTITUTION: Resistors R1, R2 of identical resistance and a capacitor C1 having an equivalent impedance are connected, in Y, with lines A, C and B. A comparator network 12 is connected with the line A through the resistor R1. A comparator 1 has an inverted input receiving the fixed reference voltage V- of a Zener diode Z1 and an non-inverted input receiving a voltage V+ obtained by dividing Vcc by resistors R4, R5. In case of correct phase sequence as shown on the figure, the voltage V+ is lower than the voltage V- and a transistor on the output side of the comparator 1 is turned on. Consequently, a current flows through a resistor R7 to turn off a transistor Tr Q1 and an opto-isolator 14 does not emit light. In case of erroneous phase sequence, a current flows through the resistors R7, R8 to turn on the transistor Tr Q1 and the opto-isolator 14 emits light. According to the arrangement, phase sequence can be determined easily.
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Inventors:
UIRIAMU AARU MANNINGU
MAAKU SHII KARUROSU
SUTANRII JIEI NASUUIKUZU
MAAKU SHII KARUROSU
SUTANRII JIEI NASUUIKUZU
Application Number:
JP30351294A
Publication Date:
October 03, 1995
Filing Date:
December 07, 1994
Export Citation:
Assignee:
TEXAS INSTRUMENTS INC
International Classes:
H02H7/097; H02H11/00; H02P23/00; (IPC1-7): H02H7/097; H02P7/36
Attorney, Agent or Firm:
Akira Asamura (3 outside)