DE1119912B - Contactless circuit that can be triggered by mechanical movement - Google Patents

Description

The invention relates to a contactless circuit that can be triggered by mechanical movement with a saturable magnetic core with a coil connected to an AC voltage source connected, and a magnet, the removal of the magnet and the saturable magnetic core to each other is mutable.

The magnetic field can be generated by a permanent magnet or an electromagnet will. The change in the influence on the nucleus is due to a relative movement between the Magnets and the core or a movement of a magnetic shunt relative to the magnet or caused to the core.

A disadvantage of such systems in various fields of application is that the voltage in the Coil windings guided around the core tend to move continuously depending on the strength of the superimposed To change the magnetic field and is not limited to two possible values that and the switch-off position of a switch or electrical contact.

It is also an arrangement for switching an alternating current through to a consumer became known, in which a choke is switched on in the alternating current circuit, which is driven by a permanent magnet is saturable and which, depending on whether the permanent magnet is applied to the throttle or is withdrawn, directs or blocks. In another known, similarly constructed device is the Permanent magnet permanently on the throttle and is the optional desaturation of the throttle through made an approaching magnetic shunt.

So it is in these known arrangements, the entire switching action by the saturation of a Coil is accomplished with a permanent magnet and the switchover is triggered by a mechanical one Movement carried out, whereby the existence of self-resonance cannot be determined.

In the circuit forming the subject of the invention there is also a capacitor in series with the coil associated with the saturable magnetic core and the coil and capacitor are dimensioned such that when the distance between core and magnet is reduced, the current in the circuit due to partial saturation of the Core and the associated reduction in the alternating current resistance of the coil through the additional magnetic field increases and an increase in the charge and voltage on the capacitor and thus an increase in the saturation effect up to a mechanical movement
Triggerable contactless circuit

Applicant:

Brookhirst Switchgear Limited, Chester,
Cheshire (UK)

Representative: Dipl.-Ing. Dr.-Ing. R. Poschenrieder,
Patent attorney, Munich 8, Lucile-Grahn-Str. 38

Claimed priority:
Great Britain February 13, 1959 (No. 5001)

William Gregson, Newton, Chester, Cheshire,

Roy Walker, Whitby,

Ellesmere Port, Wirral, Cheshire,

and Geoffrey Cooper, Marford, Wrexham,

North Wales (Great Britain),

have been named as inventors

critical point occurs where the voltage across the capacitor changes from a low to a high Value jumps, whereby a voltage is obtained on the capacitor to feed an external load, and that a second critical point can be reached when the magnet is moved away from the core at which the opposite effect occurs and the voltage across the capacitor from a high to jumps to a lower value.

According to the invention, the switchover triggering in the circuit is achieved by an abrupt structure of the Voltage accomplished across the capacitor, is thus established in the electrical system itself, so that a mechanical movement is not required for this.

According to a further essential feature of the invention, the capacitor is short-circuited for a short time, which is also done at regular intervals can take place, whereby the switching time, that is the difference between switching on and off, is reduced will. In the shift-sensitive circuit according to the invention, the switching action depends with the iron resonance and is largely independent of the core material.

109 750 / 38Π

The invention is described with reference to the embodiments shown in the drawings, without however, to limit oneself to that.

Fig. 1 shows a circuit diagram of a displacement-sensitive or saturable reaction member in which the switching effect is caused by the movement of a magnet;

Fig. 2 shows a similar circuit diagram, in which the switching effect by the movement of a magnetic shunts is effected;

Figure 3 is a circuit diagram of a switch of the type shown in Figure 1;

Fig. 4 is a shift sensitive circuit or saturable reaction member with Tools for delaying the switching time.

In Fig. 1, the current from an alternating current source consists mainly of the magnetizing current of the saturable core when the magnet M is away from the core S. Therefore, the voltage across the capacitor C is small. When the permanent magnet M is approached to the saturable core S , the current / increases according to the partial saturation of the core by the additional field of the magnet, and an additional charge appears on the capacitor C. At the beginning of each half-cycle of the supply voltage, that on the capacitor of the previous one increases Half-wave remaining charge reduces the voltage in the coil windings and thus intensifies the saturation effect. At the critical point A (FIG. 3) this effect increases and the voltage on the capacitor C jumps from a lower to a high value. This voltage can be applied to a load. In Fig. 1, this load represents a resistor R _L , which is supplied with voltage via a rectifier. Moving the magnet further towards the core changes the voltage on the capacitor only insignificantly. When the magnet is moved away from the core, another critical position is reached. The reverse process occurs and the voltage on capacitor C jumps to the low value.

In Fig. 2 the magnet is arranged so close to the core that the voltage across the capacitor has the greatest value. This voltage can be selected by moving towards or away from the magnet of a magnetic shunt K, which, for example, encloses a correspondingly shaped soft iron part. Another possibility is to place the shunt between the magnet and the core.

With either arrangement, moving the magnet or shunt to or from of the core unit, the critical switching points do not match. The main type is on a chart for a circuit according to FIG. 1 shown in FIG.

In cases where an extremely short switching time is required, a circuit according to FIG. 4 can be used. When the magnetic shunt is moved a very small distance from the critical ON point when the core unit is ON, the output voltage is toggled to the OFF state by superimposing a short pulse on the capacitor C. The capacitor C can be supplied with pulses at regular intervals, as shown in FIG. 4, with the aid of a transistor t. When the transistor base is supplied with current pulses, the transistor controls and acts on the capacitor. These current pulses can be obtained from a saturated transformer T , for example, as shown. In one embodiment of the invention, the switching time could be reduced from 0.25 to 0.01 seconds by this method. A transistor can be used to pulse multiple capacitors in different circuits. Another possibility for reducing the switching time is to interrupt the supply voltage at regular time intervals and, as already explained, the output voltage will then jump from the high value to the low.

Frequencies on the order of 2 kHz give satisfactory results. Larger coils and capacitors are required at lower frequencies. The waveform of the supply voltage is not a significant factor. A vibrator that generates rectangular waves has been successfully used. One field of application of the switch is its use in devices that control the relative displacement of two parts. Each part carries one of the two displaceable parts M and S. The displaceable parts can also form part of a mechanically operated switch, for example a push-button or limit switch with a transmission element for triggering the relative movement between the parts M and S. The resistor R can be replaced by a coil or a capacitor.

Claims (10)

PATENT CLAIMS: 1. By mechanical movement releasable contactless circuit with a saturable magnetic core with a coil which is connected to an AC voltage source, and a magnet, wherein the distance between the magnet and the saturable magnetic core is variable, characterized in that in the circuit In addition, a capacitor is connected in series with the coil mentioned and the coil and capacitor are dimensioned such that, if the distance between core and magnet is reduced, the current in the circuit due to partial saturation of the core and the associated reduction in the alternating current resistance of the coil by the additional Magnetic field grows and an increase in the charge and voltage on the capacitor and thus an increase in the saturation effect occurs up to a critical point at which the voltage on the capacitor jumps from a low to a high value, whereby a voltage on the capacitor to feed an external A larger load is obtained, and that a second critical point can be reached when the magnet is moved away from the core, in which the opposite effect occurs and the voltage across the capacitor jumps from a high to a low value. 2. Circuit according to claim 1, characterized in that the magnet (M) is arranged immovably close to the core (S) and a magnetic shunt relative to the magnet. 3. A circuit according to claim 2, characterized by one with the turns of the saturable core impedance connected in series. 4. Circuit according to one of the preceding claims, characterized by the arrangement a permanent magnet as a magnet. 5. Circuit according to one of the preceding claims, characterized in that devices arranged for sudden short-circuiting of the capacitor to reduce the switching time between higher and lower voltage are. 6. Circuit according to one of the preceding claims, characterized by a device to short-circuit the capacitor at regular intervals. 7. Circuit according to one of the preceding claims, characterized in that as Device for briefly applying the capacitor at regular intervals Transistor is arranged, the base of which is switched so ge that it is controlled by current pulses will. 8. Circuit according to one of the preceding claims, characterized in that the Current pulses are generated by a saturated transformer. 9. Circuit according to one of claims 7 or 8, characterized in that the transistor for pulse supply and short-circuiting of one or more capacitors or is used by one or more other switches. 10. Circuit according to one of claims 1 to 6, characterized in that means for Modulation of the supply voltage to shorten the switching time are provided. Legacy Patents Considered:
German patents No. 1,069,191, 1,079,114. 1 sheet of drawings © 109 750/380 12.61