SU59058A1 - Device for without rheostat empty DC electric motors - Google Patents

Description

It has repeatedly been proposed to carry out a zero-speed start of DC motors by applying short pulses using an electromagnetic switch, which simultaneously serves to protect the motor during normal operation.

The proposed device is also of the type indicated above. It differs from the known devices in that here a high-speed maximum switch with holding and switching-off coils is used as a switching device.

On the accompanying drawing schematically shows the proposed device:

1. Line switch

2. Electric motor anchor

3. Motor excitation winding

4.Contacts of the machine

5. Horn camera arc

6. Automat magnetic circuit

7. Anchor machine

8. Automatic coil retention

9. Disconnecting coil of the automaton 10. Disconnecting spring of the automaton

I. Starting device

12. Reactor

13. Discharge resistance The start of an electric motor is carried out as follows.

By turning on the linear switch 1, the excitation is fed to the excitation winding 3 of the motor 2 and the holding coil 8 of the automaton. A starting device 11 is activated, by means of which the contacts 4 of the automatic math are closed, and the measles 2 of the engine will be switched on for a full working load of the network; in this case, in series with the core, the following will be included: the disconnecting coil 9 of the automaton and the reactor 12. The inrush of current in the core circuit will cause the automaton to operate and break the circuit of the engine core. An arc has arisen, first between the contacts of the automaton and then on the horns 5 of the quenching chamber with a resistance connected in series with engine 2.

The magnitude of the current in the core circuit is determined by the steepness of the current rise, which is set by the reactor 12, by the speed

automatism machine and in the end - the resistance of the electric arc.

The arc extinguishing chamber should ensure relatively slow, IO reliable arc extinction.

If for motors with a capacity greater than 10,000 watt, the functions of the starting and protection devices are performed by a conventional unpolarized high-speed automatic with a special camera, then for motors up to 100 kilowatts it is possible to replace a high-speed automatic, somewhat similar in design to the direct-current contactor with a special quenching chamber arc.

The control circuit of the high-speed automaton must be such as to re-enable the automaton until the engine so turns up that the current surges in the core circuit are not sufficient to turn off the automaton, the automaton remains on,

In the second one, 1 gucha, i.e., for engines up to 100 kW, the starting device can be simplified by limiting the starting button. The principle of switching on the machine is the following: the start button reduces the gap (b) between the core of the magnetic core b and the core 7 by an amount sufficient to attract the core of the holding coil 8 to the flow. : on.and on and on will be noBTOp5jTbCfl until the moment when D1vigatel unfolds so that the current rush will be exact for disconnection; the engine will turn on the LINE (Key; en1m to; mains ,.

Here, the ringing control circuit means a well-known circuit in which the switching-on coil is powered through the auxiliary contacts closed when the automatic switch is turned off, and as soon as the machine is turned on, the switching-on coil circuit is broken.

Therefore, the start button must be pressed all the time the engine is started.

The inductance of the reactor should be sufficient so that the peak current does not exceed 2 times the rated current of the engine during the response time of the high-speed automat, which is usually 0.01 sec.

The machine is at the same time the maximum and minimum protection for the electric motor: the breaking roller provides maximum protection, and the holding one provides the minimum protection.

The subject matter of the invention.

A device for zero-free start-up of constant-current electric motors consisting of electromagnetism; a switching device that protects the engine from overloads during normal operating times and feeds the engine quickly with current pulses following start-up, limited by the amount of self-induction of the starting circuit and srabata time, waih of the device, characterized in that; ; edevanngo apparatus used fast max maximally maximally disconnected with a restraining side connected to the mains supplying the motor and C demagnetizing (1 switching off) the winding connected in series to the starting circuit.

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