SU657509A1 - Device for protecting electric power consumers against minimum voltage time delay - Google Patents

Description

rum connected holding capacitor and control button. The disadvantages of this device are the impossibility of connecting it to an existing consumer without stopping the technological production, and the complexity of contactless execution of the power disconnecting element, which means that this element must contain two keys, one of which must be normally closed and the other open, and when the second switch is closed, the second switch must pass a significant value of the discharge current, the time for which the capacitor is applied. The aim of the invention is to expand the functionality of the device. This is achieved by the fact that the proposed device is additionally equipped with two resistors, a transistor and a thyristor connected in parallel to the stabilizer, while the control electrode of the thyristor is connected to the collector of the transistor, the base-emitter junction of which is connected in parallel with the disconnecting element of the electrical consumer, and The first additional resistor is connected between the time of the driving capacitor and the thyristor. The drawing is a diagram of the described device. The device contains a power relay 1 with open - 2 and close 3 block contacts and contact. 4 to control the electric consumer 5, the control source b to shut off the electric power, resistor .7, zadac condensation time, capacitor 8, zener diode 9, winding of the 1P turn-holding turnips with closing contacts 11 and 12, hold the capacitor 13, control element, 15 button Control, the start element 1.6 and the power disconnect element 1, the first additional resistor 18, the connector 19, the thyristor 20, the transistor 21 and the second additional resistor 22. The device works as follows. In the presence of supply voltage and the disconnected state of the power relay 1, all elements of the device are de-energized due to the fact that element 16 is open, and the block-contact 3 of the power turn-off and contact 11 of relay 1O are also open. At the same time, the winding of the relay 1O through razmaty the block-contact 2 of the power relay 1 is shunted by a large capacitor 8 of large size, which makes it impossible to turn on the relay 10 at any level of electrical interference in external circuits and control button 15. This ensures the absence of switching on the relay 10, and consequently, the entire device in the specified mode of operation. In addition, this mode of operation is characterized by the fact that all elements included in the device circuit are de-energized. This ensures the highest possible reliability of all the elements of the circuit and the device as a whole and provides the maximum possible energy savings. At the moment of switching on the element 16, a current flows through the coil of the power relay 1, since the switching off element 17 is closed (the transistor is saturated). In this case, the power relay 1 triggers and by its block-contact 3 shunts the start-up element 16 and then when it is released, the power relay self-holds in the on state with current flowing through the block-contact 3. When the power-switch turn-off 1 block-contact 2 becomes weaker, and pin 4 switches on the consumer 5. By the voltage from the coil of the power relay 1. through the resistor 7, the driver time 8 and the holding capacitor 13 are charged until the voltage of the zener diode 9 stabilizes. The capacity of the driver capacitor 8 is more than two times higher It increases the capacitance of the holding capacitor 13 since the purpose of the capacitor 8 is to keep the relay S in the on state when the supply voltage disappears for a predetermined time, for example, 5 s, and the capacitor 13 is designed to keep the 1O relay turned on the state at the time of the transition of the power relay 1 from the disabled state of the NIN to the on state. This time is approximately one hundredth of a second. The inclusion of the relay 1O by the charge current of the capacitor 13 is impossible in the form of a large value of the resistance of the resistor 7. A feature of the described device is the possibility of using a resistor 7 with a very large value of resistance. This resistance is mainly determined by the upper limit of the magnitude of the leakage currents of the capacitors 8 and 13.

This possibility ensures a low consumption of electrical energy by the device in the operating mode (an order of magnitude less than in known devices of similar purpose); the high reliability of the device in operation due to the small currents flowing through the circuit elements and the small power dissipation of them; universality of connection to power sources which is expressed in the fact that the device can be connected to different nominal values without changing the nominal values of the circuit elements.

When the supply voltage disappears, the circuit relay 1 is turned off. In this case, the auxiliary contact 3 and contact 4 of the power relay 1 are opened, and the auxiliary contact 2 is closed. The holding capacitor 13 is discharged through the contact block 2, and turnip Yu is connected in parallel with the charged capacitor 8. The operation of turnip 10 causes its contact 11, which is connected parallel to the start element 16, to close. This state of the relay, Yu, is maintained for a well-defined delay time (for example, -5 s), the capacitance-defined time of the set of capacitor 8 and the winding resistance of turnip Y.

If the supply voltage is restored within a specified time, the power relay 1 automatically turns on without element 16, since the coil of this relay remains connected to the supply voltage via pin 11 of relay 10

If the supply voltage is exceeded after a given vrioumeni, then the power relay 1 will not be able to automatically turn on -, due to the fact that pin 11 of the relay Yu will be open by this time.

In case of short-term supply voltage disappearances, the time that causes the capacitor 8 to be discharged partially. The loss of energy stored by the capacitor 8 is determined by the de-energized state of the coil of the power relay 1. The smaller the time for the disappearance of the supply voltage, the smaller the loss of energy stored by the capacitor and the less time it takes to recover it.

Due to the fact that the loss of energy of the charged capacitor 8 during short-term blinking of one-by-one disappearance of the supply voltage occurs partly with its subsequent restoration when the network voltage appears, the device is able to keep the power turnip in the on state for a significantly greater time than the specified delay time.

When the Stop signal is received from the source 6 of the power supply disconnection control, the disconnecting element 17 goes into a low conductivity state, and a current begins to flow through the base-emitter junction of the transistor 21 and resistor. The collector current of this transistor includes a thyristor 2O,

5 through which the time of the increments of the capacitor 8 is completely discharged. The resistor 18 is designed to limit the discharge current of the capacitor 8 to the current allowed through the thyristor 20. Simultaneously due to a decrease in the current through the power relay 1 to the value determined by the resistor 22, the power contact 3 the relay opens and the device returns to its original state.

five

The device has a periodic control of the health of the circuit. For example, a filament lamp, a dial gauge, a signal fluorescent lamp, and the like can be used as the control element 14. In this case, a filament lamp was used as a control element 14, connected in series with contact 12 of relay Y. This relay contact may be closing or opening depending on the selected control mode — dark or light. For example, with the closing contact 12, the control element 14 is in the carton when the coil state is on

0 power relay 1.

When the control button 15 is pressed, it turns on, its contact 12 closes and current flows through the control element 14 due to the voltage applied to the coil of the power relay 1 during the holding time of the relay 10 in the on state.

The proposed device allows

/ simplify the power disconnecting element and ensure that the device can be connected to the current consumer of electricity without interrupting technological production.

, Simplification of the power consumption disconnection element is achieved due to the fact that the Stop button in the device can be used with one normally closed BGM contact or when