JPH0447666Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention This invention relates to a disconnection detection circuit for a differential transformer.

(b) Purpose of the invention This invention provides a switch that short-circuits one of the secondary coils of a differential transformer, turns off the switch, excites the primary coil with an AC signal, and connects it to the secondary coil. When the voltmeter reading is zero,
An object of the present invention is to provide a disconnection detection circuit for a differential transformer, which detects disconnection of a primary coil or a secondary coil from the fluctuation of a voltmeter by connecting a switch.

(c) Example of the invention Next, a configuration diagram of an example of the invention is shown in FIG. 1.

1 in Figure 1 is the oscillator, 2A is the primary coil, 2B
and 2C is the secondary coil, 2D is the core, 3 is the voltmeter,
4 is a switch.

The differential transformer 2 is composed of 2A to 2D, and has a terminal 22 of the secondary coil 2B and a terminal 2 of the secondary coil 2C.
3 is connected.

Voltmeter 3 is connected between terminal 21 of secondary coil 2B and terminal 24 of secondary coil 2C.

When the primary coil 2A is excited with an AC signal from the oscillator 1, the position of the core 2D is adjusted, etc.
Adjustment is made so that when the outputs of the secondary coil 2B and the secondary coil 2C are equal, the reading on the voltmeter 3 becomes zero.

The core 2D has a primary coil 2A and a secondary coil 2B,
It is held so that it can be moved between cores 2C and 2C, and when core 2D is moved, the output of the secondary coil on the moved side increases. Therefore, the mechanical position of the core 2D can be converted into an electrical signal, and the differential transformer 2 is used as a means for electrically detecting the mechanical displacement.

Primary coil 2A, secondary coil 2B, 2 in Fig. 1
C The wire may be disconnected.

In such cases, conventionally a resistance meter or the like is used as a means of detecting disconnection, but this idea
By simply adding a switch 4 to FIG. 1, the peripheral circuitry of the differential transformer 2 is utilized to detect a disconnection of the differential transformer 2.

The switch 4 is connected to short-circuit the terminals 21 and 22 of the secondary coil 2B, but in normal use, the switch 4 is turned off.

Note that the switch 4 may be connected to both ends of the secondary coil 2C, and the switch 4 may be connected to both ends of the secondary coil 2B and secondary coil 2C.
may be provided for each.

When switch 4 is off, the reading on voltmeter 3 will be zero in the following two cases. One is the secondary coil 2
This is a case where the output of B and the output of the secondary coil 2C are equal,
The other case is when the differential transformer 2 is disconnected.

To detect a disconnection, apply an AC signal from oscillator 1, and when voltmeter 3 indicates zero, switch 4
be in contact with

When the voltmeter 3 does not swing, it is determined that the primary coil 2A or the secondary coil 2C is disconnected, and when the voltmeter 3 swings, the primary coil 2A or the secondary coil 2C is disconnected. It is determined that it has not been done.

(d) Effects of the invention According to this invention, a switch is provided on the secondary coil side to short-circuit the secondary coil, and the switch is closed only when checking for wire breakage. No errors occur.

Furthermore, since a disconnection check can be performed simply by adding a switch, the configuration can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment according to this invention. 1... Oscillator, 2... Differential transformer, 2A...
Primary coil, 2B...Secondary coil, 2C...Secondary coil, 2D...Core, 3...Voltmeter, 4...Switch.

Claims (1)

[Claims for utility model registration] Primary coil 2A, first secondary coil 2B, second
has a secondary coil 2C, and a first secondary coil 2B.
and the second terminal 22 of the second secondary coil 2C.
The differential transformer 2 connects the terminal 23 of the first secondary coil 2B and the third terminal 21 of the first secondary coil 2B and the second
In a differential transformer circuit constituted by a voltmeter 3 connecting a fourth terminal 24 of a secondary coil 2C, the first terminal 21 of the first secondary coil 2B and the second
A switch 4 is provided to short-circuit the terminal 22 of the
A disconnection detection circuit for a differential transformer, characterized in that when the indication is zero, a switch 4 is turned on, and disconnection of the differential transformer 2 is detected by the presence or absence of vibration in the voltmeter 3.