JPH0363579A - Disconnection detection circuit in differential transformer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disconnection detection circuit in a differential transformer.

[Problems to be solved by conventional technology and invention]

Conventionally, various disconnection detection circuits have been proposed for electrical circuits, but a differential type that can reliably detect all disconnections at the primary winding terminal of a differential transformer, the center tap of the secondary winding, and the left and right ends thereof Since the circuit configuration of a disconnection detection circuit in a transformer has been complicated, the present invention provides a detection circuit with a simple circuit configuration.

[Means to solve the problem]

Primary winding 1 and center tap (b) to which voltage Vf is applied
), a δ smoothing circuit 3 that smooths the voltages Ea1 and Ec1 generated at the left and right ends (a) and (c) of this center tap ■, respectively, and a δ smoothing circuit 3 that smooths the voltages Ea+ and Ec+, respectively. A differential transformer is provided with a comparator 4 for comparing the pressures Ea2 and Ec2, and detects the displacement of the control rod 5 inserted into the secondary winding 1 and the secondary winding 2 based on the output value of the comparator 4. a, the left and right ends (a) of the center tap ■, (
c) are grounded through resistors 6, respectively, and the left and right ends (a),
(c) shows the voltage Ea+%Be generated between the center tap (b) and the left and right ends (2) and O, and the reference voltage E. Connect disconnection detection comparators A and B to compare I and the left and right ends ■, O
Detecting the disconnection at the voltages Eal and Ec.

is applied to the addition circuit 7, and a disconnection detection comparator C for comparing the output voltage of the addition circuit 7 and the reference voltage EOI is connected to the addition circuit 7, and the voltage is applied to the primary winding terminals (d), (e) or the center tap. This invention relates to a disconnection detection circuit in a differential transformer characterized by detecting disconnection in (2).

〔Example〕 FIG. 1 illustrates and describes a preferred embodiment of the present invention.

An AC voltage V is applied to terminals (a) and (c) of the primary winding 1, a voltage V is applied to the center tap 2 of the secondary winding 2, and the left and right ends (a A smoothing circuit 3 is provided to smooth the voltages Eat%Eat generated in ) and (c), respectively, and the voltages Eat, Ea smoothed by this smoothing circuit 3 are
t is input to a comparator 4, and the left and right ends (a) and (c) of the center tap (b) are connected to resistors 6, respectively, to a differential transformer a that detects the displacement of the control rod 5 based on the output value of the comparator 4. Ground through.

Further, disconnection detection comparators A and B for comparing the voltage Eal4c and the reference voltage E are connected to the left and right ends (2) and O of the center tap (2), respectively.

Further, an adder circuit 7 that applies the voltages E a t and E c 1, respectively, is connected to the adder circuit 7.
output voltage and reference voltage E. Connect a disconnection detection comparator C that compares 3 and 3.

Next, the operation of this embodiment will be described in detail.

! , Normal case with no wire breakage - When primary voltage v1 is applied to secondary winding 1, secondary voltages Va and Vc are applied between the center tap (b) of secondary winding 2 and the left and right ends ■ and @. This secondary voltage Va is generated.

A voltage EaI% 201 obtained by superimposing a voltage Vf connected to the center tap 2 on Vc, respectively, is smoothed by a smoothing circuit 3, and the smoothed voltages Eat and Eat are input to a comparator 4.

When the position of the control rod 5 inserted into the primary winding 1 and the secondary winding 2 is displaced, the values of the secondary voltages Va and Vc change, and the voltage E
als Eat changes, thereby smoothing the voltage E
Since the values of al and Eat change and the output value of the comparator 4 changes, the position of the control rod 5 is detected based on this output value.

Voltages Ear and ECI are applied to disconnection detection comparators A and H, but Ell and Eat are secondary voltages va.
Even if lVc becomes the lowest voltage, it does not become lower than the reference voltage E□ of the open circuit detection comparator A1B, and no matter where the control rod 5 is, the result is that it is always higher than the reference voltage EOI. , B.

The addition circuit 7 also has a voltage E smoothed by the smoothing circuit 3.
c8 and Eat are applied respectively, and if the reference voltage of this adder circuit 7 is Sat, then as a result, Ea=+Bc*-
A voltage Eat is input to the disconnection detection comparator C. In the disconnection detection comparator C, this EOI + Eat in normal condition
The reference voltage Eo is set to a value smaller than the voltage −Eat.
Since the control rod 5 is compared with s, the smoothed voltage Ea becomes smaller or Eat becomes smaller regardless of the position of the control rod 5, but the added voltage Eat+Ect
Since Ea3 is always constant, the disconnection detection comparator C outputs a result that it is always higher than the reference voltage Ea3.

2. When a disconnection occurs (i) When a disconnection occurs at the left and right ends ■ or @ Since the left and right ends (a) and (c) are each grounded through the resistor 6, the disconnected terminal (■ At the same time, the secondary voltage Vc or vc at the end or the O end becomes zero, and at the same time, EOI or Eat also becomes a zero potential, and this zero potential is output to the breakage detection comparator A or the breakage detection comparator B. Then, the reference voltage E of the disconnection detection comparator A or B. Since I is set higher than the zero potential, a result is output that the reference voltage E is higher than the disconnection detection comparator A or B, which is reversed from the normal state.

(If a disconnection occurs in the center tap [F] of 311, the voltages Ea, Ec, become vf, respectively, and are smoothed and applied to the adder circuit 7, resulting in Vf+Vf
The voltage Eot is output to the disconnection detection comparator C, but it is lower than the normal voltage value, and the reference voltage EC9 of the disconnection detection comparator C is set higher than this voltage Vf + Vf - Eot. , the reference voltage E from the disconnection detection comparator C is reversed from the normal state. The result that 3 is larger is output.

(iiD - If a disconnection occurs in the next winding terminals ■ and ■ -
Since no voltage is generated in the secondary winding 1, the primary voltage V is not induced to the secondary side, and Ea2 and Ec2 become Vf, respectively, just like when center tap 0 is disconnected. is inverted and output from the disconnection detection comparator C to the reference voltage E.

, is larger.

Therefore, when a disconnection occurs, one of the disconnection detection comparators A,
Reference voltage E from BSC. Is Ill: The result that a3 is thicker is output.

This example will be described in more detail.

- When an AC voltage V is applied to the secondary side, the amplitude value 4 is applied to the secondary side.
The configuration is such that a secondary voltage valvC of V is generated between the center tap [F] and the left and right ends (a) and (c), respectively.

Since the voltage Vf connected to the center tap 0 is set to 3V, the voltage Ea1% EC1 is an alternating current voltage that alternates with an amplitude of 4V around 3V and has a minimum voltage of 1V.

Therefore, each reference voltage E of the disconnection detection comparator ASB. I
is set to a value smaller than this minimum voltage IV and larger than zero.

The addition circuit 7 also outputs a voltage Ea smoothed by the smoothing circuit 3,
, Eat, and its reference voltage E. , 25
When normal, this adder circuit 7 outputs a smoothed voltage Ea! , Ecz are applied, and 4.5V is output to the disconnection detection comparator C. Center tap [F]
Alternatively, if a disconnection occurs in the primary winding terminals (a) and (c), Ea2 and Ec2 will each become Vf (C3V), so the adder circuit 7 will calculate Vf + Vf Eat, that is, 3V.
+3V-2,,5V = 3.5V is output to the disconnection detection comparator C.

Therefore, the reference voltage E. , is smaller than the above 4.5v and the above 3
゜It is set to 4■ which is larger than 5V. That is, when the wire is disconnected, the reference voltage E is applied from the adder circuit 7. 3. Lower than 4V of 3.
Since 5V is output to the disconnection detection comparator C, the output of the disconnection detection comparator C is inverted.

In addition, when a disconnection is detected by any of the disconnection detection comparators A, B, and C, the output becomes "L", so the transistor 8 is turned off, the diode 9 is energized, and the thyristor IO is turned on. , LSD 11 and a buzzer 12 are connected to the disconnection detection comparators A1B and C.

Also, although not shown, each disconnection detection comparator A, B.

It is also possible to easily determine the location of the wire breakage by providing an alarm device for each of the wires.

〔Effect of the invention〕

Since the present invention is configured as described above, it can be easily configured and reliably connects the primary winding terminals ■ and ■ and the center tap of the secondary winding [
It is possible to obtain a disconnection detection circuit in a differential transformer that can reliably detect disconnections of F] and its left and right ends ■ and @.

[Brief explanation of drawings]

FIG. 1 is a wiring diagram showing one embodiment of the present invention. ! ...-Secondary winding, 2... Secondary winding, 3... Smoothing circuit, 4... Comparator, 5... Control rod, 6... Resistor, 7
... Addition circuit. Flat bottom 1 year July 31st

Claims (1)

[Claims] Primary winding and center tap with voltage Vf applied (b)
A smoothing circuit that smoothes the voltages Ea_1 and Ec_1 generated at the left and right ends (a) and (c) of this center tap (b), respectively, and a voltage obtained by smoothing the voltages Ea_1 and Ec_1, respectively. A differential transformer a is provided with a comparator that compares Ea_2 and Ec_2, and detects the displacement of a control rod inserted into the primary winding and the secondary winding based on the output value of the comparator.
The left and right ends (a) of the center tap (b),
(c) are grounded through resistors, respectively, and the left and right ends (a),
(c) center tap (b) and left and right edges (a), (c)
The voltages Ea_1, Ec_1 generated between the reference voltage E
Disconnection detection comparators A and B are connected to compare the voltages Ea_2 and Ec_2 to the adder circuit, and the voltages Ea_2 and Ec_2 are added to the adder circuit. A disconnection detection comparator C that compares the output voltage of the circuit and the reference voltage E_0_3 is connected, and the primary winding terminals (d), (
A disconnection detection circuit in a differential transformer, characterized in that it detects disconnection at (e) or center tap (b).