SU1494065A1 - Synchronizing device - Google Patents

Abstract

The invention relates to switching devices, in particular, to synchronous switches. The purpose of the invention is to expand the operational capabilities by providing synchronization in the field of both large and small currents. In the mode of disconnecting small currents in the circuit consisting of elements 12, 16 and 15, a resonant mode takes place. The phase shift between the primary and secondary currents in the current transformer 12 is close to 90 °, which ensures that when the button 11 is pressed, the closure of the contacts 8, 10 of the reed switch must be prevented relative to zero current in the power contacts 1. In the mode of high currents, the zener diodes 13,14 An additional capacitor 16 is punched and shunted. This changes the phase shift between the primary and secondary currents of the current transformer 12, which allows the required advance current to be preserved. 1 il.

Description

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The invention relates to switching devices, namely synchronous switches.

The purpose of the invention is the expansion of operational possibilities by providing synchronization in the field of both large and small currents.

Figure 1 is a schematic diagram of the device; Figures 2 and 3 show the current curves in the windings of the current transformer, respectively, in the low and high current shutdown mode.

The device contains power contacts 1, an inductively dipamic drive with a core 2 and a coil 3, a thyristor 4 connecting the drive coil 3 to the accumulator (11de) to the collector 5, the thyristor control circuit 4, consisting of a control capacitor 6, a resistor 7, a switching contact group 8 , 9 and 10 of the reed switch and control buttons 11, the current transformer 12, the secondary winding of which is connected via zener diodes 13 and 14 to the reel 15 of the reed switch and additional capacitor 16.

The device works as follows.

In the mode of disconnection of small currents in the circuit formed by elements 12, 16 and 15, resonance takes place, i.e. The inductive resistance of the secondary winding of the current transformer 12 is compensated by the capacitor 16 capacitance, and the phase shift between the primary and secondary currents (figure 2) of the current transformer is close to 90. The parameters of the specified circuit from elements 12, 16 and 15 are chosen such that the operation level of the reed switch IQ . provides the necessary anticipation t of the moments of jamming of contacts 8 and 10 with respect to the zero value of the primary current. When the start button 11 is pressed in time interval A (FIG. 2), when contacts 8 and 9 of the reed switch are closed, the start-up capacitor 6 is charged through resistor 7. When current i reaches ip, the reed switch contacts and contacts 8 and 10 closes. Capacitor 6 is discharged on the controlled transition of thyristor 4 and thyristor 4 is unlocked. In this case, the storage capacitor 5 is discharged to the coil 3 of the drive, which leads to the opening of the power contacts 1 before the current transition through zero. With

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pressing the start button 11 in the interval B, when contacts 8 and 10 of the reed switch are closed, the thyristor 4 remains in the closed state until the end of this stage.

In the high current off mode, when the current i increases by about 50-100 times, the voltage on the secondary winding of the current transformer 12 increases. The Zener diodes 13 and 14 unlock and shunt the additional capacitor 16, which excludes the occurrence of resonance in the secondary circuit of the current transformer 12. Therefore, the current iq increases v not in proportion to the current i, but significantly less - by 20-40 times. The secondary winding of the current transformer has the nature of an active-inductive load and at the same time the current ill is slightly ahead of the current i ((FIG. 3). In this case, the moments, operation and release of the reed switch are close to zero current 1 (2, and the resistance of the winding 15 of the reed switch chosen so as to create a phase shift between the currents if and i (}, which provides a given pre-emption t. The operation of the control circuit in the high-current disconnection mode occurs in the same sequence as in the disconnection of small currents.

The proposed device allows to provide the required current advance in the entire range of the disconnected currents and thereby eliminates the appearance of overvoltages during current slices in the synchronous vacuum circuit breakers.

Claims (1)

Invention Formula A synchronization device containing power contacts with an inductive-dynamic drive, a thyristor, a storage capacitor, a starting capacitor, a resistor, a reed switch with a switching contact, a start button, a current transformer and an additional capacitor, the power contacts, the primary winding of the current transformer are connected to the serial circuit, inductive winding of the on-dynamic drive, thyristor and storage capacitor form a closed series circuit, start-up capacitor, resistor NO contact reed switch connected in a series circuit, one terminal tcp ogp torn t from