SU1427472A1 - Electric machine protection arrangement with emergency duty sensor - Google Patents

Description

(21) 4205441 / 24-07

(22) .87

(46) 09/30/88. Bul Number 36

(71) Pavlodar Industrial Institute

(72) M.Ya. Kletsl, A.N. Novozhilov and V.E. Polkov

(53) 621.316.925С088.8) (56) Fedoseev A.M. Relena protection of electrical systems. M .: Energie, 1976, p. 599.

USSR author's certificate number 1046852, cl. H 02 K 11/00, H 02 K 7/08, 1983.

(54) DEVICE FOR PROTECTION OF ELECTRIC MACHINE WITH EMERGENCY SENSOR

(57) The invention relates to electrical mechanics and can be used to protect against damage / penetration of the power cable and the stator winding of an electric machine against short circuits. The purpose of the invention is to increase the sensitivity and enhance the functionality of the protection. The device contains an electric machine 1 with a built-in block 2, a second and a third reed switch 13.14 with windings 15.16 and

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17,18,19 and contacts 24,26. With the closure of a small number of turns of the stator winding of the machine, the current of the phases remains almost unchanged, and the output of the built-in protection block 2 and, therefore, increases in the windings 15, 17 of the second and third reed switches 13,14. As a result

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 The invention relates to electrical engineering and can be used to protect against damage to the power cable I and the stator winding of an electric machine against short circuits.

The purpose of the invention is to increase the sensitivity and extend the range of protection.

The drawing shows the functional diagram of the proposed device. properties.

Device for protection of electric machine 1 with built-in unit 2 - contains a zero-sequence current transformer 3, two current transformers 4 and 5, the first reed switch 6 with one winding 7, short-circuit 8 and opening 9 contacts, series-connected element MEMORY H and relay 11 time, the reactive body 12 made in the form of the second and third reed switches 13 and 14 with two 15.16 and three 17,18,19 control windings, respectively, while the first control winding 15 of the second 13 and the first control winding 17 phase The company unit 20 and the control winding 7 of the first reed switch 6 are connected to the output of the built-in unit 2, the second control winding 16 of the second reed switch 13 is connected to the output of the zero sequence current transformer 3, the second 18 and the third control coil 19 of the third reed switch 14 are connected in series with the secondary switches by the currents of transformers 4 and 5 of the third and first phase currents and with the first 21 and second 22 power direction relays, which are connected through a voltage transformer 23 to the supply mains through their voltage inputs, make 8 contacts of the first

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In this case, the sum of the magnetic fluxes de-energized on the second and third reed switches 13, 14 differs from zero. The contacts 24, 26 of the reed switches are closed and act on the control circuit of the switch 29 by disconnecting the machine 1 from the supply: network. 1 il.

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20

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reed switch 6 through contacts 24 of the second reed switch 13, element MEMORY 10 and contacts 25, time relay 11 connected in series with element MEMORY 10, as well as contacts 26 of the third reed switch 14 and series-connected disconnecting contacts 27.28 relays 21 and 22 of power direction i are connected the control circuit of the switch 29, and the disconnection of the contacts 9 of the first reed switch 6 through the winding of the alarm relay 30 and the contacts 31 of the switch position are connected to the terminals of the operating current source. The number of turns of the control windings of the second 13 and third 14 reed switches is chosen such that in trouble-free modes the total magnetic fluxes acting on the contacts of the reed switches 13 and 14 are zero. For the same purpose, phase-turning unit 20 serves.

The device works as follows.

In the start, self-load and idle modes, the unbalance current of the built-in unit 2, which has flowed through the windings 7.15 and 17 of the first, second and third reed switches 6.13 and 14, closes the contacts 8 of the first reed switch 6. The second and third reed switches 13 and 14 do not close the contacts, since the total effect of the magnetic field on them is zero.

With the closure of a small number of turns of the stator winding of the machine, the current of the phases practically does not change, and at the output of the integrated unit 2 and, therefore, in the windings 15 and 17 of the second and third reed switches increases. As a result, the sum of the magnetic fluxes acting on the second and third reed switches

13 24 13 well

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14, differs from zero. Press contacts

26 of the second and third reed switches 14 are closed and the machines are disconnected from the network.

When interfunctional circuit in the power cable, i.e. between current transformers 3,4 and 5 and the terminals of the machine 1, the current in the windings 15 and 17 of the second

containing a reacting organ, a switch with a control circuit connected to the output terminals, and with power contacts for switching in series into each phase wire of an electric motor, differs from the fact that, in order to increase the sensitivity and expansion of the third reed switches 13 and 14 amending the protection action, it additionally

c slightly, and at the outputs of transformers 4 and 5 of the current and in the windings 19 and 18 sharply increases.

but it is equipped with two current transformers, a zero-sequence current transformer, a voltage transformer, two, a power direction relay, a phase shifter, the first reed switch with a control winding, with closing and opening contacts connected in series by the MEMORY element and a time relay, an alarm relay and the reacting unit is designed as a second and third reed switch with two and three windings

As a result, the contacts of the third reed switch are closed and the machine is disconnected from the network.

In the case of a single-phase closure in the power cable, the current at the output of the transformer 3 of the zero sequence current and the winding 16 of the second reed switch 13 increases dramatically, and at the output of the built-in unit 2 and, therefore, in the windings 15 and 17 of the second and third reed switches remains unchanged. The contacts 24 of the second reed switch 13 are closed, start the time relay 11, which, after about 1s, disconnects the machine 1 from the network.

but it is equipped with two current transformers, a zero-sequence current transformer, a voltage transformer, two, a power direction relay, a phase shifter, the first reed switch with a control winding, with closing and opening contacts, connected in series by an element MEMORY and a time relay, an alarm relay, and the reacting unit is made in the form of the second and third reed switches with two and three windings of the control control winding of the second and first 25 control windings of the third reed switches are connected through a phase return separate block and winding of the first reed switch with switch output terminals, second control winding of the second reed switch connected

In the event of a short circuit of the network (with zero current transformer output

its short circuit) the magnetizing forces of the windings 15 and 16 of the second reed switch 13 are equal, the contacts 24 of the second reed switch 14 remain in the open position, the contacts 26 of the third reed switch 14 are closed, and the contacts 27 and 28 of the first and second relays 21 and 22 of the power direction open. Machine 1 is not disconnected from the network.

In the event of a damage to the connecting cable (breakdown, short circuit), the windings 7.15 and 17 of the first, second and third reed switches 6.13 and 14 are de-energized, and contacts 24 and 26 are closed. Contacts 9 start the relay 30 and interrupt the circuit to shut off.

Claims (1)

The technical and economic efficiency of the proposed device consists in increasing the sensitivity of the protections to various types of short circuits, which makes it possible to reduce the time for simple and repair, and consequently, the magnitude of damage from an accident. Invention Formula Device for the protection of an electrical machine with an emergency alarm sensor. 1IIG1I Order 5979 bench press containing a reacting organ, a switch with a control circuit connected to the output terminals, and with power contacts for connecting in series to each phase wire of an electric motor, differs from the fact that, in order to increase the sensitivity and expansion of the but is equipped with two current transformers, a zero-sequence current transformer, a voltage transformer, two, a power direction relay, a phase shifter, the first reed switch with a control winding, with closing and opening contacts connected in series by the MEMORY element and a time relay, an alarm relay, and the reacting unit is designed as a second and third reed switch with two and three control windings20 the control winding of the second and first 25 control winding of the third reed switch is connected via the phase rotation unit and the winding of the first reed switch to the output terminals of the switch, the second control winding of the second reed switch is connected the sequence that controls the sum of the phase currents of the motor, the second and third control windings of the third reed switch are connected in series with the secondary windings of the third and first phase current transformers and the first and second power direction relays, which are connected to terminals for connection with the Pitacian network, closing the contacts of the first reed switch through the first circuit of sequentially connected short-circuit contacts of the reed switch, the MEMORY element and the time relay contacts, as well as through the second parallel circuit connected in parallel to the first one of the third reed switch closing contacts, the first and the second power direction relay opening contacts are connected to the switch output terminals, and the alarm relay coils and contacts The position of the switch is connected to the terminals of the operating current source. razh 651 subscription