SU1534543A1 - Explosion-safe electromagnetic starter - Google Patents

Abstract

The invention relates to mine explosive electromagnetic starters designed for remote control and protection of electric drives of mining machines and mechanisms. The purpose of the invention is to increase safety and reduce weight and size. The device is equipped with a synchronization unit for disconnecting the power contacts of two separate contactors, and these power contacts are connected in series. This allows the use of contactors that have a lower switching capacity than the switching capacity of the entire starter, and therefore a lower mass of moving parts, which ensures high mechanical durability and reliability. 1 hp f-ly, 1 ill.

Description

The invention relates to mining electrical engineering, to mine explosion-proof electromagnetic actuators, intended for remote control and protection of electric drives of mining machines and mechanisms.

The purpose of the invention is to increase safety and reduce weight and size.

The drawing shows a diagram of an explosion-proof electromagnetic actuator.

The starter consists of two contactors, the power contacts 1 and 2 of which are connected in series and included in the power circuit, windings 3 and 4 of electromagnetic drives and contactors, a capacitor 5, a direct current source including a transformer 6 and a rectifying bridge 7, devices 8 remote control, the closing contact of which 9 is included in the power supply circuit of the executive relay 10, the closing contact 11 of this relay is included in the power supply circuit of the windings of the electromagnetic drives of the contactors, unit 12 overcurrent protection, contact Act 13 of which is also included in the supply circuit of the windings 3 and 4 electromagnetic

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contactors, diode 14, resistor 15, shunt diode 14, limiting capacitor 16, shunted by auxiliary contacts 17 and 18 of contactors, auxiliary disconnecting contacts 19 and 20 of both contactors connected in parallel to the second closing contact 21 of the executive relay and connecting windings of the executive relay to the rectifying bridge through terminals 22 and 23 for connecting a direct current source. The capacitance C of the capacitor is chosen such that

1 R2

(the inequality was observed --- m-2,

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where R and L are the total active resistances and inductances of the windings of the electromagnetic drives with the diode 14, the resistor 15 and the capacitor 5 form a disconnect synchronization unit 24.

The starter works as follows

at once.

When a signal is sent to the control unit 8, it triggers the output relay of the unit (not shown) and closes its contact 9 in the executive relay circuit 10, which operates, closes the contact 11 and thus connects the windings 3 and 4 of the electromagnetic drives to the rectifier bridge. As a result, the electromagnetic drives are triggered, which leads to the closure of the power contacts 1 and 2 of both contactors. During the operation of the contactors, the auxiliary contacts 17-20 of both contactors open. However, the current circuit in the windings 3 and 4 of the electromagnetic drives is not interrupted, since a capacitor 16 is connected in series with the rectifying bridge, by means of which the current in the windings 3 and 4 of the electromagnetic drives is reduced, Executive Relay 10 also remains in the on state, since its power supply circuit remains closed through its own contact 21. Therefore, the contactors remain on, and their power contacts and 2 are closed.

The actuator is disconnected when there is a disconnection signal supplied to the block 8 "At the same time the contact 9 in the circuit performer 5 digs

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five

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relay, which opens contact 11 in the circuit of the windings 3 and 4 electromagnetic actuators of contactors. The electromagnetic actuators are disconnected, as a result of which the power contacts 1 and 2 are open, breaking the actuator power circuit.

The synchronization block of the contactors ensures the oscillatory nature of the decrease in the windings of the electromagnetic drives, thus achieving speed and synchronism of the disconnection.

If for any reason one of the contactors remains in the on state and its power contacts are closed, the next switching on of the actuator is excluded, since the power supply circuit of the executive 10 is broken. This mode (welding of the contactor contacts when switching off to a ke or switching off k0z. ) in a known starter causes serious accidents, as the supply of voltage to a mining machine without a control signal leads to its spontaneous start.

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Consistently connecting power kongkch-on dchukh separate contactors in the presence of a synchronization unit disconnecting their drives allows the use of contactors in explosion-proof electromagnetic actuators that have a lower switching capacity than the switching capacity of the entire starter, and therefore a smaller mass of moving parts, which ensures a high mechanical wear resistance and reliability. The reduced weight of the moving parts of the contactors as compared with special mining contactors, the creation of an oscillatory process in the coils of their electromagnets, ensures a high response rate when disconnecting

The total volume of the two contactors is 2-3 times less than the volume of the special mine contactor. Placing two contactors with small dimensions in a cylindrical explosion-proof sheath of starters makes it possible to fill the sheath volume more fully than with a single large contactor, it makes it possible to reduce the size and weight of the entire explosion-protected device.

Claims (2)

1. An explosion-proof electromagnetic starter containing a contact block with power contacts and an electromagnetic drive, an actuating relay with a closing contact, a protection unit with an interrupting contact and leads for connecting a direct current source, and the contacts of the executive relay and the protection block are connected in series to the power supply circuit. electromagnetic drive of the contactor unit, characterized in that, in order to increase safety and reduce weight and dimensions, it is equipped with a lock-off synchronization unit of tactors including a diode, a resistor and a capacitor, the contactor unit is made in the form of two contactors, the switching capacity of each of which is less than the switching capacity of the starter, the power contacts of these contactors are connected in series, the control windings of the electromagnetic drives of the contactors and the diode are also connected in series, the resistor connected in parallel to the diode and the capacitor in parallel to the series circuit formed by the control windings of the electromagnetic drives of the contactors and the diode m, the capacitor leads are connected to the leads for connecting a constant current power source 3 +. 4j6 through the closing contact of the fire relay and the closing contact of the protection unit, the diode being connected in the conducting direction with respect to the polarity of the leads for connecting the DC power source, and the capacitance C of the specified capacitor is chosen so that 1 R7 10 observed inequality where R and L are the total active resistances and inductances of the windings of the electromagnetic drives. 15 2. A starter pop., Distinguished by the fact that the closing contact of the remote control unit was inserted into it, an electromagnetic relay with two closing contacts was used as an executive relay, contactors with an auxiliary opening contact were used as contactors, and the auxiliary disconnecting contacts of both contactors are connected in series with each other; the specified serial circuit is shunted by the second closing contact of the actuating relay, and the parallel circuit is connected to the coupling of the executive relay, the terminals for connecting the DC source and the closing 35 contact remote control unit. Sostayitgiy Yu, Ben t1 Editor G Volkova Tehred L. Serdyukov .-- Proofreader 0. Cmile Order 46 Circulation 457 VNINPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 4/5, Moscow, Zh-35, Raushsk nab. 113035 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 Subscription