JPS58157332A - Phase opposition relay - 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 The present invention relates to an anti-phase relay, and particularly to an anti-phase relay that detects erroneous connection of a three-phase motor and prevents problems caused by reverse rotation of the motor.

A three-phase motor is driven by a supply current of 93 phases with a phase difference of 1200 degrees, and each phase is supplied to the motor correctly.
In other words, by connecting to the positive phase, the motor can rotate in the forward direction.However, if the motor is accidentally connected to the opposite phase, the motor will reverse and the device connected to the motor may be destroyed. The motor itself also suffers from problems such as damage due to overload. In order to prevent reverse rotation due to such motor connection errors, an anti-phase relay is connected to the motor main circuit, which detects the anti-phase connection state from the load current of the motor main circuit and opens the main circuit based on this detection signal. Ru.

The configuration of a conventional anti-phase relay is shown in FIG. 1, in which the load current supplied to a three-phase motor (not shown)
0, and this detection signal is output to the anti-phase detection circuit 12.

The anti-phase detection circuit 12 analyzes the detection signal from the current transformer 10 and determines whether the motor connection is in positive phase or anti-phase, and when the connection is in anti-phase, an anti-phase signal is output.

The anti-phase signal is output to a relay circuit 14, and only when the anti-phase signal is input to the relay circuit 14, the relay circuit 14 is activated and the motor main circuit is opened.

As a result, it is possible to prevent the motor from reversing due to an incorrect motor connection, that is, an anti-phase connection, and it is possible to avoid an accident that destroys the device connected to the motor.

However, in this type of device, the motor connection state is constantly determined regardless of whether the motor is started or the motor is in steady operation. When an abnormal signal is input, under the influence of this abnormal signal, the detection circuit 12 determines that the actual connection state is in an out-of-phase state even though it is in a normal phase state, and the main circuit is opened. There was a drawback.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to reliably determine the anti-phase connection state of the motor at the time of starting the motor, and to detect abnormalities such as noise input during steady operation of the motor. It is an object of the present invention to provide an anti-phase relay that does not malfunction due to signals.

In order to achieve the above object, the present invention analyzes nine detection signals detected by a three-phase motor device to determine whether the motor is connected to a positive phase or a negative phase, and when the motor is connected to a negative phase, a negative phase signal is detected. An anti-phase relay that includes an anti-phase detection circuit that outputs an output, and a relay circuit that opens a main circuit when the anti-phase signal is input, detects the start of the motor and outputs a start signal for a predetermined time after starting the motor. The present invention is characterized in that a start detection circuit is provided, and the main circuit is opened by a relay circuit (marked with @) only when the anti-phase signal and the start signal are both output.

Hereinafter, preferred embodiments of the present invention will be explained based on the drawings.

FIG. 2 shows a schematic configuration of the anti-phase relay according to the present invention, and the same members as those in the conventional device are given the same reference numerals, and the explanation thereof will be omitted.

A characteristic feature of the present invention is that a start detection circuit is provided which detects the start of the motor and outputs a start signal for a predetermined period of time after the motor starts, and only when the antiphase signal and the start signal are output together, the relay circuit The structure is such that the main circuit is opened.

In this embodiment, when the load current is detected by the current transformer 10, that is, when the motor is started, the current transformer 10
A command signal is output from the start detection circuit 16 to the start detection circuit 16.

The activation detection circuit 16 is comprised of, for example, a timer circuit, and outputs a activation signal for a predetermined period of time, for example 10 seconds, when the command signal from the current transformer 10 is input.

The activation signal and the anti-phase signal from the anti-phase detection circuit are both supplied to an AND circuit 18, and the AND circuit 18 outputs an activation signal to the relay circuit 14 only when both of the above signals are input. When the activation signal is input to the relay circuit 14, the relay circuit 14 is activated and the main circuit is opened.

Therefore, according to this embodiment, when starting the motor,
When the motor is in the anti-phase connection state, both the start signal and the anti-phase signal are output to the AND circuit 18, so that the main circuit is opened, and the adverse effects caused by the reverse rotation of the motor are reliably prevented.

On the other hand, during steady operation of the motor, that is, the start detection circuit 16
After the output of the start signal is stopped, the AND circuit 18
Therefore, even if an abnormal signal such as noise is input to the anti-phase detection circuit 12 and an anti-phase signal is output from the nuclear detection circuit 12, the activation signal is not relayed from the AND circuit 18. The drawbacks of the conventional device, such as not being output to the circuit 14 and the main circuit being opened due to malfunction, are definitely eliminated.

As explained above, according to the present invention, if it is possible to reliably determine the anti-phase connection state of the motor at the time of starting the motor, malfunctions may occur due to abnormal signals such as human input noise during steady operation of the motor. It is possible to provide a highly reliable antiphase relay that never fails.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional anti-phase relay, and FIG. 2 is a block diagram showing a schematic configuration of the anti-phase relay according to the present invention. Identical members in each figure are given the same reference numerals; 10 is a current transformer; 1 is a current transformer;
,. 2 is an antiphase detection circuit, 14 is a relay circuit, and 16 is a start detection circuit. Agent Patent attorney Shin Kuzuno - (1 other person) Figure 1 Figure 2

Claims (1)

[Claims] (11) A current transformer that detects the load current of the three-phase motor main circuit, and a detection signal detected by the current transformer is analyzed to determine whether the motor is connected in the normal phase or in the opposite phase. The anti-phase relay includes an anti-phase detection circuit that outputs an anti-phase signal when the anti-phase signal is input, and a relay circuit that opens the main circuit when the anti-phase signal is input. An anti-phase 1 loop characterized in that a start detection circuit is provided which outputs a start signal for a fixed period of time, and the main circuit is opened by the relay circuit only when both the anti-phase signal and the start signal are output. .