JPH0540680Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field to which the idea belongs]

This invention is a relay used to detect the phase order of a wired three-phase power supply and to prevent the motor from rotating in reverse when connected in reverse phase order, and is equipped with a resistor, a capacitor, and a control relay. , the capacitor and the control relay coil each form each phase of a three-phase star circuit, and the resistor, capacitor, and control relay coil are connected to the relay coil by the coil only when the three-phase power supply rotates in phase. The present invention relates to a reverse phase prevention relay in which a control relay is operated by applying a voltage that enables the electrical contacts to be driven.

[Prior art and its problems]

As this type of negative phase prevention relay, one with a basic circuit shown in FIG. 5 is known. This relay includes a resistor 1, a capacitor 2, and a control relay 3, in which the resistor 1, capacitor 2, and coil 3a of the control relay form each phase of a three-phase star circuit, and the resistor, capacitor, and control relay coil Only when the three-phase power supply phases rotate in the order of
A voltage that can drive the electrical contacts driven by the control relay coil is applied to the control relay to operate the control relay, and the direction of the phase rotation of the three-phase power source matches the arrangement order of the resistor-capacitor-control relay coil. In the case of reverse phase in the opposite direction, only a low voltage is applied to the control relay coil, and the control relay does not operate. Therefore, as a method for supplying current to a load, for example, a three-phase induction motor, only when the direction of phase rotation of the three-phase power supply, that is, the phase order matches the arrangement order of the resistor-capacitor-control relay coil, is the positive phase. At this time, the electrical contacts of the control relay 3 are turned on, and a main circuit controller such as a magnetic contactor, which opens and closes the main circuit from the three-phase power supply to the load, is connected between the output terminals C and NO, which become conductive. Connecting the coils is done. Therefore, with such a reverse phase prevention relay, immediately after connecting the three-phase power supply,
To determine whether the phase is normal or reversed, the only way to determine is to press the turn-on button on the main circuit controller and assume that it is in phase if it operates, and if it does not operate, it is in reverse phase. In addition to requiring time and effort, the disadvantage is that power is continuously and unnecessarily supplied to the coil of the control relay unless the reverse phase prevention relay is disconnected from the power supply circuit after the determination.

[Purpose of invention]

This invention eliminates the above-mentioned conventional drawbacks, and
It is an object of the present invention to provide a reverse phase prevention relay that does not require time and effort to determine reverse phase, has a determination function, and can easily avoid unnecessary power consumption by being supplied to a control relay coil after determination. purpose.

[Key points of the idea]

This device includes a resistor, a capacitor, and a control relay, and the resistor, capacitor, and control relay coil each form each phase of a three-phase star circuit, and the resistor, capacitor, and control relay coil are connected to a three-phase power supply in this order. In a reverse phase prevention relay in which a control relay is operated by applying a voltage to the relay coil that enables driving of an electric contact driven by the coil only when the phase rotates, the three-phase power source is connected and the terminal screw is connected. The resistor and capacitor are housed in a case that has output terminals at both ends that have terminal screws for pulling the electric contacts of the control relay to the outside and connecting external electric wires, and the control relay is connected to the control relay. Equipped with an indicator light that flashes through electrical contacts driven by a relay coil, and configured to be detachable from the case, it is possible to distinguish between positive and negative phases of a three-phase power supply connection without using parts or wiring. This is made possible by the indicator light of the control relay without any addition, and after the determination, the control relay is removed from the case of the reverse phase prevention relay, and power consumption is continuously supplied to the control relay coil unnecessarily. The aim is to prevent

[Example of idea]

Figures 1 to 3 show a plan view, a side sectional view, and a bottom view of a negative phase prevention relay structure according to an embodiment of the present invention, and Figure 4 shows an electric circuit in the control relay of this negative phase prevention relay. Show the configuration. The power supply terminals R, S, and T of each phase of the three-phase power supply each have a terminal screw, and the electrical contact 3b that is turned on or off depending on the operating state of the relay in the control relay 3 are pulled out to the outside and external electric wires are connected. Output terminal C with terminal screw to connect, NC and
A resistor 1 and a capacitor 2 constituting two phases in a three-phase star circuit for determining the connection state of a three-phase power supply are built into the case 4, and a coil 3a constituting the third phase is incorporated into the case 4. Control relay 3 with built-in
As shown in FIG. 2, the insertion terminal 3z is provided on the lower end surface, and is inserted into the socket 5 attached to the case 4 to establish an electrical contact position between it and the sliding contact of this socket. It is removably attached to the case while forming a . As shown in FIG. 4, the control relay 3 is further provided with an electric contact 3c that operates in the same manner as the electric contact 3b.
An indicator light 3d is interposed between this contact and the coil 3a. This indicator light uses a light-emitting body such as a neon tube or a light-emitting diode that can be lit by the line voltage applied via the capacitor 2 and the coil 3a, which exhibits an impedance on the order of several to several tens of kilohms at the operating frequency. . In this embodiment, the indicator light 3d is connected to the electrical contact 3b when the three-phase power supply is connected to the positive phase.
3c is driven to the right and lights up, but the electrical contact 3
It is also possible to provide a reverse phase prevention relay that lights up when the reverse phase connection is made by changing the connection between C and the power supply terminal S so that the light is lit in the state shown in the figure. In addition, in FIGS. 1 and 2, the reference numeral 6 indicates the socket 5.
This is a stopper to prevent the control relay inserted into the control relay from falling off.When the control relay is inserted, the tip is pushed open, and after insertion, the tip bends inward to prevent the relay from falling off. Reference numeral 7 is a cover that closes the bottom of the case 4, and FIG. 3 shows a view of the inside of the case from the bottom with this cover removed. Reference numeral 8 indicates a part of the wiring inside the case 4. In addition, in Fig. 1, the indicator light 3d
Although indicated by a broken line, the cover of the control relay is made of a transparent synthetic resin molded product, like a normal relay, and can be viewed through the transparent cover.

[Effect of the idea]

As described above, according to the present invention, the reverse phase prevention relay is configured such that the control relay and the case are detachable, and the control relay is provided with an indicator light that blinks through its electrical contacts. This allows you to easily distinguish between the positive and negative phases of the three-phase power supply wiring, and once you have confirmed that the phase order is correctly connected, the phase order will remain the same until the next time you replace the wiring. Since it is impossible for the wiring to reverse, the control relay can be removed from the case immediately after checking the wiring condition, thereby eliminating wasteful power consumption by the control relay coil and indicator light. .

[Brief explanation of the drawing]

1 to 3 are a plan view, a side sectional view, and a bottom view showing the structure of a reverse phase prevention relay according to an embodiment of the present invention, respectively, and FIG. 4 is a control of the reverse phase prevention relay shown in FIGS. 1 to 3. FIG. 5 is a circuit diagram showing an example of an electric circuit configuration within a control relay in a conventional negative phase prevention relay. 1...Resistor, 2...Capacitor, 3...Control relay, 3a...Control relay coil, 3b, 3c...
...Electrical contact, 3d...Indicator light, 4...Case,
R, S, T...three-phase power terminal, C, NO, NC...
...Control relay output terminal.

Claims (1)

[Scope of utility model registration request] Comprising a resistor, a capacitor, and a control relay, the resistor, capacitor, and control relay coil each form each phase of a three-phase star circuit, and the three-phase power supply rotates in phase in the order of the resistor, capacitor, and control relay coil. In the reverse phase prevention relay, the control relay operates only when a voltage that enables driving of the electric contacts driven by the coil is applied to the relay coil, and the three-phase power supply is connected to a power terminal having a terminal screw. The resistor and capacitor are housed in a case provided with output terminals at both ends having terminal screws for drawing out the electrical contacts of the control relay to the outside and connecting to an external power supply,
A negative phase prevention relay, characterized in that the control relay is provided with an indicator light that blinks through an electric contact driven by the control relay coil, and is configured to be detachable from the case.