RU28293U1 - DEVICE FOR PROTECTING DC ELECTRIC CARS FROM OVERLOAD - Google Patents

Abstract

A device for protecting DC electric machines from overload, containing a DC voltage source, the first and second outputs of which are connected to the first and second inputs of the disconnecting key, the first output of which is connected through a series excitation winding of the electric machine, the second output of which is connected to the input of the DC electric machine, the output of which is connected to the first output of the starting rheostat, the fuse, the input of which is connected to the second output of the disconnecting key, is which is equipped with an electromagnetic relay, the first output of which is connected to the first output of the disconnecting switch, and the second output is connected to the second output of the fuse, connected in parallel with the fuse by an electric circuit from a signal lamp and a current-limiting resistor connected in series, a protective diode of the operating circuit, the cathode which is connected to the second terminal of the fuse, and the anode to the second terminal of the starting rheostat, an auxiliary electrical circuit, consisting of sequence potentiometer connected, an additional direct voltage source, an additional fuse, the protective diode in the conductive direction, the contact of the electromagnetic relay, the input connected to the second output of the disconnector and the output - to the second terminal of the fuse.

Description

2002121410

tlHI

CONSTANT ELECTRIC MACHINE PROTECTION DEVICE

CURRENT RESET

The utility model relates to electrical engineering and electric power industry and can be used for supplying electric DC machines and other power electrical devices from overload.

A device 1 is known for running electrical installations from current overload, comprising a current sensor, a potentiometer, a relay, an amplitude converter, diodes, resistors, and a direct current source.

Known 2 device for current protection of electrical machines, containing resistors, a linear temperature-voltage Converter.

There is also known 3 device for protecting a DC source from overload, containing a fuse, a key element, a relay, a current sensor, resistors, diodes potashchometr, capacitor.

A disadvantage of the known protection devices is that they do not provide the necessary protection in the operating mode, since the rated currents of the fuses are rated 1Y for the currents of electrical machines at starting conditions, which significantly exceed the rated currents of operation of power electrical devices.

The closest in technological essence to the proposed device for protecting DC electric machines from overfreezing is the device for switching on a series direct current electric motor 4 selected as a brush cutter, containing a disconnecting key, fuses, a constant voltage source, a starting rheostat.

A disadvantage of the known prototype is the inability to provide the necessary protection for electric maphangs in operating mode.

The objective of the utility model is to increase reliability, namely, to increase the sensitivity of protection to overloads of electric DC machines in operating mode.

.ш-MPK Н02НЗ / 08 To achieve the specified technical result

a device for protecting DC electric cars from overfreeze, containing a DC voltage source, the first and second outputs of which are connected to the first and second inputs of the disconnecting key, the first output of which is connected through a series excitation winding of the electric tire, the output of which is connected to the input of the DC electric machine, output which is connected to the first output of the starting rheostat, a fuse, the input of which is connected to the second output of the disconnecting key, is equipped with an electric a magnetic relay, the first output of which is connected to the first output of the disconnect switch, and the second output is connected to the second output of the fuse, connected in parallel with the fuse} e) an electric circuit from the signal lamp and a current-limiting resistor connected in series, with a protective diode of the working circuit, the cathode of which is connected with the second terminal of the fusible pre-defailer, and the anode with the second terminal of the starting rheostat, an auxiliary electric circuit, consisting of series connected in series RA, an additional source of constant voltage, an additional fuse, a protective diode in the conducting direction, an electromagnetic relay contact connected by an input to the second output of the disconnecting device, and by an output to the second output of the fusible pre-plug

Comparative analysis with the prototype shows that the claimed device for protecting electric DC machines from overload is characterized by the presence of an electromagnetic relay and its contacts, an additional protector, two protective diodes, an interconnecting lamp, a current-limiting resistor, and an additional source of constant voltage.

In FIG. 1 shows a block diagram of a device. The device for protecting electrical DC machines from overload, figure 1, contains a constant voltage source 1, the first and second outputs of which are connected respectively to the first and second inputs of the disconnecting

2 keys 2, the first output of which is connected via winding

serial excitation of the electrical machine 3, and the second output with the first output of the fuse 4, the second output of which is connected to the cathode of the protective diode of the working circuit 5, the anode of which is connected to the first output of the starting rheostat 6, an electronic DC machine 7, the input of which is connected to the second the input winding of the series excitation of the electric machine 3, and the output with the first output of the starting rheostat 6, the electromagnetic relay 8, the first output of which is connected to the first output of the disconnecting switch 2, and the second the output is connected to the second output of the pre-fuse 4, connected in parallel with the fuse 4 is an electric circuit from a signal lamp 9 and a current-limiting resistor 10, an auxiliary electric circuit consisting of a series-connected potentiometer 11, an additional constant voltage source 12, an additional fuse 13, a protective diode in conductive direction 14, contact 15 of the electromagnetic relay 8, connected by the input to the second output of the disconnecting switch 2, and the output to the second fuse pin 4.

When the isolation switch 2 is closed, the voltage from the constant voltage source 1 through the series winding of the electric machine 3, fuse 1 fuse 4, the protective diode of the operating circuit 5, the starting rheostat 6 is supplied to the DC electric machine 7. The rated current of the fuse 4 must be calculated based on starting currents of the electric machine, Fig.Z (graph 1).

When the disconnect switch 2 is closed, the electrical relay 8 is activated, after a certain period of time determined by the inertial properties of the electromagnetic relay 8, the contact of the electromagnetic relay 4 is closed and the auxiliary current circuit is closed, Fig.2. An additional fusible chfedotanilite 14 serves to protect against overloading the constant voltage source 12. Using the potashchometra 11 changes the current of the auxiliary circuit.

///

3 Nd of FIG. 3 shows the starting characteristic of the electrical

DC machines (graph 1).

When you turn on the current circuit of FIG. 2, the operating current of the electric motor is in the form of FIG. 3 (graph 3):

I slave. 1rv6.

where 1o - ziachenne current due to the additional electrical circuit of figure 2. and by heating the fusible pre: plywood 4 (graph 5);

1rab. -value of the operating current of the electric machine 7 of Fig. C (graph 2).

Thus, the value of the operating current will be close to the value of the rated current of the fuse 4.

During normal operation of the electric DC machine, the signal lamp 9 does not light.

In emergency operation of the DC electric machine 7, fuse 4 fails, the electromagnetic relay contactor 15 opens, disabling the auxiliary electrical circuit of FIG. 2. The signal lamp 9 lights up, indicating that the electric machine 7 is disconnected from the constant voltage source 1. Dsh1 to exclude the possibility of currents flowing from the additional constant voltage source 12, an emergency diode 5 is used.

The diode 14 protects an additional source of constant voltage 12 from the working currents of the electric machine 7.

Sources of information:

1. Acting certificate of the USSR No. 1267521, IPC Н02НЗ / 08.1986.

2. Aetorsk certificate of the USSR No. 1504709, IPC Н02Ю / 08.1989.

3. The author's certificate of the USSR No. 1261039, IPC Н02Ю / 08, 1986.

4.Piotrovsky L.M. Electric cars. Uch. for techies. -L.: Energy, 1974. -504s.

4

Claims (1)

A device for protecting DC electric machines from overload, containing a DC voltage source, the first and second outputs of which are connected to the first and second inputs of the disconnecting key, the first output of which is connected through a series excitation winding of the electric machine, the second output of which is connected to the input of the DC electric machine, the output of which is connected to the first output of the starting rheostat, the fuse, the input of which is connected to the second output of the disconnecting key, is which is equipped with an electromagnetic relay, the first output of which is connected to the first output of the disconnecting key, and the second output is connected to the second output of the fuse, connected in parallel with the fuse by an electric circuit from a signal lamp and a current-limiting resistor connected in series, a protective diode of the operating circuit, the cathode which is connected to the second terminal of the fuse, and the anode to the second terminal of the starting rheostat, an auxiliary electrical circuit, consisting of sequence potentiometer connected, an additional direct voltage source, an additional fuse, the protective diode in the conductive direction, the contact of the electromagnetic relay, the input connected to the second output of the disconnector and the output - to the second terminal of the fuse.