JPS59155906A - Demagnetizing circuit of dc exciting electromagnetic coil - 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] [Technical field to which the invention pertains] The present invention provides a circuit for demagnetizing a DC-excited electromagnetic coil, particularly an electromagnetic coil of an electromagnetic switch, by a demagnetizing shunt connected to the coil, An electronic switch that opens and closes depending on the excitation voltage is connected in series with this electromagnetic coil, and a degaussing circuit is connected in parallel with this switch.

[Prior art and its problems]

As a prior art related to such a degaussing circuit, Patent Application No. 3232 of the Federal Republic of Germany filed by the present applicant is known.
217.8-. There is No. 33 (named ``Circuit device for degaussing a DC-excited electromagnetic coil'' filed in Japan on a separate date in August of 1920, hereinafter referred to as the previous application).

In this prior art, an electronic switch that opens and closes depending on the value of the excitation voltage applied to the electromagnetic coil is connected in series to the electromagnetic coil, and a nonlinear resistor is connected in parallel to the electromagnetic coil. This made it possible to shorten the opening delay time of switches operated by electromagnetic coils at a small cost, but it became necessary to freely adjust or select the opening delay time depending on the purpose of use. Sometimes, it is not always easy to adjust and select the opening delay time using only such prior art means.

[Purpose of the invention]

The object of this invention is to improve the alliteration circuit so that the opening delay time of the electromagnetic υ11 switch can be extended from its minimum value to "IFA adjustment" as necessary.

rSummary of the Invention This object is achieved by further connecting another resistor in parallel to the parallel circuit of the electronic switch and the non-linear resistor. Also, from this resistance l, the FAl primary nonlinear resistance a) energy negative IJ decreases. If this resistor is adjustable, the opening delay time can be adapted to desired conditions in the field without the need to replace the resistor.

[Embodiments of the invention]

The present invention will now be described in detail with reference to drawings showing a circuit based on the previous application and a circuit based on the present invention.

In Figure 1, which shows a circuit based on the above-mentioned 1fjfl,
A full-wave rectifier circuit consisting of diodes 4+5+6+7 is connected to the diodes 1 and 21 via the switch 3. The DC voltage output end of the full-wave rectifier circuit is connected to a diode 10 through terminals 8 and 9. Resistor 11 and Zener diode 12
is connected to a series circuit consisting of a parallel circuit of a capacitor 15 and a resistor 16. A non-IK line resistor 17 is connected in parallel between the drain and source lead lines of the field effect transistor 13, and here this resistor is a varistor. Drain of field effect transistor 13.

The parallel circuit between the source lead wire and the varistor 17 has one connection point connected to the terminal 9 and the other connection point connected to the electromagnetic coil 7+/
1.4 is connected to one lead wire, and the other lead wire of the small electromagnetic coil is connected to ψ'11i wire 8.

When the switch 3 is closed, a full-wave rectified pulsating DC voltage is applied to the terminal 8.9. Terminal 8 is a positive electrode, and terminal 9 is a negative electrode. The voltage between terminals 8 and 9 is the Zener voltage of Zener diode 12 and the threshold of diode 10.
? As long as the voltage exceeds the phase with the diode 10.
An auxiliary current flows through the resistor 11 and the Zener diode 12, and this auxiliary current causes a Zener voltage drop across the Zener diode 12. Zener diode 12) Due to this voltage drop, the field effect trial risk 13, which can be controlled without power, becomes conductive, so the electromagnetic coil 1
4 is excited. The circuit σ) consisting of a capacitor 15 and a resistor 16 has a time constant such that the field effect transistor 3 remains conductive even during periods of periodic dips in the DC voltage σ) applied between terminals 8 and 9. Be selected.

When the switch 3 is opened, the voltage strip between the terminals 8 and 9 suddenly drops to a value twice the forward voltage drop σ) of the diodes 4 to 7. Camping point 15 is Zener diode 1
2, the Zener diode 10 is blocked by σ), which is connected to the direct voltage, and the Zener diode 12. Capacitor 15 and resistor 16 are separated from terminal 8.
]7ru. Then, the capacitor 15 is discharged through the resistor 16, and the field effect transistor 13 is placed in a blocking state.

7 IA current of electromagnetic coil) Risk of commutation 17
1. The force 5, Paris, ri 17 arises from this 'P! The voltage is set so as to exceed the maximum allowable voltage between the drain and source of the field effect transistor by one degree. 3F
The energy stored in the energizing coil J4 is dissipated rapidly and without causing damage.

In FIG. 2 showing an example of the circuit of the previous application (No. 20 of the Komototsu circuit), a delay normally closed contact 18 of an electromagnetic switch is inserted and connected between the diode 4 and the terminal 8. By opening the normally closed contact 18, the full-wave rectifier circuit is switched to a half-wave rectifier circuit. Demagnetizing shunt 1 or two diodes 5
．． The half-wave rectifier circuit consists of diodes 5 and 6. When the delayed normally closed contact 19' opens, a resistor is inserted in front of the electromagnetic coil 14. The holding power of the electromagnetic coil is thus significantly reduced.

Due to half-wave rectification, the voltage between the terminals 8 and 9 is lost every half wave, so the field effect transistor is connected to the RC circuit 15, lf' so as to remain conductive during this voltage drop period.
The time constant of i is chosen to be large compared to the circuit shown in FIG. However, for this reason, the opening delay time of the electromagnetic switch will increase compared to the circuit shown in Figure 1. Based on this reason, (7) The anode of the diode 21 is connected to the connection point 22. The cathode of the diode 21Q is connected to the connection point B between the diode 10 and the resistor J1. This causes the missing half-wave of the auxiliary current. is complemented by A. At this time, the diode 10 is in the blocking state O), and the half-wave rectifier l'1i
Avoid switching to 12 circuits from becoming invalid.

Such a circuit eliminates the need to increase the time constant of the RC circuit.

In FIG. 3 showing a third circuit example of a circuit based on M+i output Bt4H, the switch 2.1 is straddled on the side of the DC source for exciting the electromagnetic coil 14. Again, in order to ensure that the energy stored in the electromagnetic coil 1.1 disappears, D: 12 8, 911! Dimate 5 is connected to l, and this damate 17
Close the demagnetizing coil 14 through Ballistaev. The insertion of this diode (IHO) has the additional effect of reducing burnout of the control switches 2 and 1.

Figures 1 to 6 show that the circuits shown in Figures 1 to 3 are
A circuit according to the invention is shown in which a variable resistor is connected in parallel to the drain-source circuit and the resistor 17 in parallel to the drain-source circuit. This variable resistance extends the opening delay time of the electromagnetic switch beyond its minimum value. When the resistance value is set to infinity, the opening delay time is adjusted to the minimum value. When the resistance value is set by the circuit r1i4', it is adjusted to the original opening delay time that would have been set if the circuit based on the previous application was not used. Additionally, the variable resistance reduces the energy load of non-linear resistances.

〔Effect of the invention〕

This invention is a circuit for demagnetizing a DC excitation electromagnetic coil, especially an electromagnetic coil of an electromagnetic switch, by a demagnetizing shunt connected to this coil, and an electronic switch that opens and closes depending on the excitation voltage is connected to the electromagnetic filter. In the circuit based on the previous application in which the electronic switch and the non-linear resistor are connected in one negative column and a non-linear resistor is connected in parallel with this switch, there is a Connect the resistors in parallel.

With this configuration, when the switch on the power supply side is opened and the field effect transistor is in a blocking state, the residual current of the electromagnetic coil is commutated from the field effect transistor to the nonlinear resistor and another resistor, thereby creating a demagnetizing shunt. The energy stored in the electromagnetic coil is rapidly dissipated as thermal energy in these resistors, shortening the opening delay time of the electromagnetic switch. As the resistance of another resistor is varied from infinity to zero, the opening delay time is adjustable from a minimum value.

This additional resistance also reduces the energy load of the non-linear resistance.

This is the circuit diagram.

In the drawing, 13 is an electronic switch (field effect transistor), 14 is an electromagnetic coil, 17 is a nonlinear resistor, and 26
is another resistance.

Claims (1)

[Claims] 1) A circuit for demagnetizing a DC excitation coil, particularly an electromagnetic coil of an electromagnetic switch, by a demagnetizing shunt connected to this coil, which is an electronic type that opens and closes depending on the excitation voltage. Here's the switch. In a degaussing circuit that is connected in series to the electromagnetic coil and a non-linear resistor is connected in parallel to this switch, another resistor is connected in parallel to the parallel circuit of the electronic switch and the non-i-line resistor. A degaussing circuit for a DC-excited electromagnetic coil, characterized in that: 2. The circuit according to claim 1, characterized in that the resistance is adjustable.
Coil demagnetization circuit.