Relay coil built-in diode anti-reverse polarity detection circuit and detection method thereof

Abstract

The invention provides a relay coil built-in diode anti-reverse polarity detection circuit and a detection method thereof, the relay coil built-in diode anti-reverse polarity detection circuit comprises a detected relay, the coil anode of the detected relay is connected with the cathode of a power supply, the coil cathode of the detected relay is sequentially connected with a resistor and a switch, and the switch is connected with the anode of the power supply. And an ampere meter is arranged between the tested relay and the power supply. Under the condition that the relay is normally switched, failure short circuit of the diode of the relay coil Z1 can be detected, and whether the diode has a reverse polarity prevention function or not is judged. And the risk of continuous use of the relay coil Z1 diode under the condition of failure and short circuit is reduced.

Description

Technical Field

[0001] The invention relates to a relay coil internally-installed diode anti-reverse polarity detection circuit and a detection method thereof. Background Art

[0002] A certain type of relay coil has two diodes built in, diode Z1 is connected in series with the coil, and diode Z2 is connected in parallel with the coil. The coil is a self-inductance coil, and the diode has a unidirectional conductive characteristic. Diodes Z1 and Z2 are freewheeling diodes. When the coil is powered off, the coil will release its own stored energy and generate a reverse electromotive force of about 280V (10 times the rated voltage of the coil 28V). This electromotive force will be consumed by the circuit formed by the freewheeling diode and the coil. Therefore, the role of diode Z2 is freewheeling, and diode Z1 is a protection diode to prevent the reverse electromotive force generated by the power failure of the coil from flowing to the external circuit. When the relay passes the rated voltage to the coil according to normal logic, if the pins Z1+ and Z1- of the built-in Z1 diode in the relay coil are short-circuited, the relay can also switch and work normally, but the Z1 diode in the relay coil no longer has the function of preventing reverse polarity. If the relay is used when the Z1 diode in the relay coil does not have the function of preventing reverse polarity, when the rated voltage is reversely passed to the relay coil, the relay will show abnormal phenomena. After the relay is assembled, a corresponding circuit is added externally to detect the reverse polarity protection function of the Z1 diode installed in the relay. For example, CN102818992A discloses a relay detection device, including a microprocessor, a keyboard module, a display module, a power module, a relay drive module, an action frequency detection module and a current detection module electrically connected to the relay drive module, and a temperature detection module connected to the relay. It uses a microprocessor to detect the relay, which greatly increases its cost. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a relay coil internal diode anti-reverse polarity detection circuit and a detection method thereof.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a relay coil internal diode anti-reverse polarity detection circuit and a detection method thereof, comprising a relay to be tested, wherein the positive pole of the coil of the relay to be tested is connected to the negative pole of a power supply, the negative pole of the coil of the relay to be tested is connected to a resistor and a switch in sequence, the switch is connected to the positive pole of the power supply, and an ammeter is arranged between the relay to be tested and the power supply.

[0006] The voltage of the power supply is the same as the voltage of the relay being tested.

[0007] The current value displayed by the ammeter determines whether the diode in the relay under test is faulty.

[0008] The current is a current limiting resistor.

[0009] A method for detecting reverse polarity of a diode installed inside a relay coil, the steps of which are as follows:

[0010] S1, close the switch for 1 to 5 seconds and then open the switch;

[0011] S2. Observe the reading of the ammeter and determine whether the diode in the relay under test has failed.

[0012] If the ammeter reading is zero, it is determined that the diode built into the relay is not failed.

[0013] If the ammeter has a reading, it is judged that the diode inside the relay has failed.

[0014] The beneficial effect of the present invention is that it can detect the failure and short circuit of the relay coil Z1 diode under the condition of normal relay switching, and judge whether the diode has the function of preventing reverse polarity, thereby reducing the risk of continuing to use the relay coil Z1 diode under the condition of failure and short circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the principle of the present invention;

[0016] In the figure: 1-power supply, 2-switch, 3-resistance, 4-relay under test, 5-ammeter. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0018] A relay coil internal diode anti-reverse polarity detection circuit and detection method thereof, comprising a relay to be tested, wherein the positive pole of the coil of the relay to be tested is connected to the negative pole of a power supply, the negative pole of the coil of the relay to be tested is connected to a resistor and a switch in sequence, the switch is connected to the positive pole of the power supply, and an ammeter is arranged between the relay to be tested and the power supply.

[0019] The voltage of the power supply is the same as the voltage of the relay being tested.

[0020] The current value displayed by the ammeter determines whether the diode in the relay under test is faulty.

[0021] The current is a current limiting resistor.

[0022] A method for detecting reverse polarity of a diode installed inside a relay coil, the steps of which are as follows:

[0023] S1, close the switch for 1 to 5 seconds and then open the switch;

[0024] S2. Observe the reading of the ammeter and determine whether the diode in the relay under test has failed.

[0025] If the ammeter reading is zero, it is determined that the diode built into the relay is not failed.

[0026] If the ammeter has a reading, it is judged that the diode inside the relay has failed.

[0027] like Figure 1 As shown, in the present application, when the relay is operating normally, the circuit for detecting whether the Z1 diode in the relay coil has the function of preventing reverse polarity is connected to the relay, including a power supply with the same rated voltage as the relay under test, a resistor R1 with the same resistance as the relay coil under test, an ammeter, a switch and the relay under test. Figure 1 Resistor R1, ammeter, switch and relay under test are connected in series with the power supply, the positive lead wire of the power supply is connected to the switch, the switch is connected to the resistor lead wire, the other lead wire of the resistor is connected to the negative pole of the relay coil under test, the positive pole of the relay coil under test is connected to the positive terminal of the ammeter, and the negative terminal of the ammeter is connected to the negative pole of the power supply. The main purpose is to connect the negative pole of the coil of the relay under test to the positive pole of the power supply, and the positive pole of the coil of the relay under test to the negative pole of the power supply.

[0028] Power supply: Provides voltage to a circuit.

[0029] Switch: The opening and closing of the switch determines whether the circuit is connected.

[0030] Ammeter: Whether the ammeter displays the current value can determine whether the diode inside the relay under test is faulty.

[0031] Relay under test: The device being tested.

[0032] Resistor: Protects the diode in the relay.

[0033] Since the diode Z1 built into the relay coil under test is a protective diode, it has the function of preventing reverse polarity and can prevent the reverse electromotive force generated by the coil power failure from flowing to the external circuit. When the switch is turned off, the power supply is energized (the voltage is consistent with the rated voltage of the relay under test).

[0034] When the switch is closed, the circuit is connected. If the Z1 diode installed in the relay coil under test has not failed, the ammeter should have no current value. If the Z1 diode installed in the relay coil under test has failed, the ammeter will display the current value.

Claims

1. A relay coil built-in diode anti-reverse polarity detection circuit, characterized in that: The device comprises a relay to be tested, wherein the positive pole of the coil of the relay to be tested is connected to the negative pole of the power supply, the negative pole of the coil of the relay to be tested is connected to a resistor and a switch in sequence, the switch is connected to the positive pole of the power supply, and an ammeter is arranged between the relay to be tested and the power supply.

2. The relay coil internal diode anti-reverse polarity detection circuit as claimed in claim 1, characterized in that: The voltage of the power supply is the same as the voltage of the relay being tested.

3. The relay coil internal diode anti-reverse polarity detection circuit as claimed in claim 1, characterized in that: The current value displayed by the ammeter determines whether the diode in the relay under test is faulty.

4. The relay coil internal diode anti-reverse polarity detection circuit as claimed in claim 2, characterized in that: The current is a current limiting resistor.

5. The method for detecting the reverse polarity of a diode installed inside a relay coil as claimed in claim 1, wherein the steps are as follows: S1, close the switch for 1 to 5 seconds and then open the switch; S2. Observe the reading of the ammeter and determine whether the diode in the relay under test has failed.

6. The method for detecting reverse polarity of a diode built into a relay coil as claimed in claim 5, characterized in that: If the ammeter reading is zero, it is determined that the diode built into the relay is not failed.

7. The method for detecting reverse polarity of a diode built into a relay coil as claimed in claim 5, characterized in that: If the ammeter has a reading, it is judged that the diode inside the relay has failed.

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