SU961028A1 - Hoisting installation electric drive current protection apparatus - Google Patents

Description

one

The invention relates to electrical engineering, in particular, to the protection of electric drives of direct current against overloading and can be used, for example, as a current protection of an electric drive of a rolling lifting installation.

A device for overcurrent protection of an electric drive is known, which contains a time relay, an impedance and an executive relay (maximum differential relay) 1.

A disadvantage of the known device is the lack of flexibility and accuracy of the formation of protective current charts.

It is also known a motor overcurrent protection device containing a motor core current sensor, the output of which through a filter unit is connected to the second input of the adder, through the first switch to the input of the memory unit and through the second switch to the first input of the adder, the output program of the current protection modes whose outputs are connected with enter ladies first. and second switches, as well as with the first inputs of the emergency unit

protection and alarm unit, the output of the memory unit is connected via the second switch to the first input of the adder, the output of which is connected simultaneously to the second input of the emergency protection unit and to the second input of the warning unit 2.

One of the significant drawbacks of the known device is that it does not take into account the unbalance of the lifting of the installation during the formation of the protective current diagram. This reduces the accuracy of the current diagram and, as a result, the sensitivity of the protection.

Another significant disadvantage of the known device is the lack of reliability of the protection, which is as follows. In the known device, the current setting is determined by a signal from the current sensor kor, fixed in

Claims (2)

20 memory block by the time the hoist reaches the specified acceleration. It is possible that the fixation of the signal in the memory unit will occur at the time of the overload of the lifting motor, and as a result, the current setting will be incorrect to protect its device. the functions are not fulfilled and the reliability of the protection is not ensured. The aim of the invention is to increase the sensitivity and reliability of protection. This goal is achieved by the fact that a sensor unit, including a sensor unit, the output of which is functionally connected to the execution and signaling unit, is additionally inserted into the device for current protection of the lifting unit; the lock sensor, the track pulse sensor and the weight sensor of the load, the integration unit, the voltage source unit, the setting task unit, the task setting and stroke control unit, straightening A spruce and a comparison unit, the output, the setting unit of the settings is connected to the first input of the summation unit, to the second input of which is connected via the integration unit the outputs of the lock sensor and the track pulse sensor, the load weight sensor being connected to the input of the voltage source unit, the first output of which is connected with the third input of the summation unit directly, and the remaining outputs - with the remaining inputs (summation shock - through the task and control unit, the output of the summation unit is connected to the first input of the unit and comparison, to the second input of which is connected via a current rectifier cor,. the output of the comparison unit is connected to the execution and alarm unit. FIG. 1 shows a functional diagram of the proposed device; in fig. 2 is a diagram of voltages U at the outputs of the blocks and the speed of lifting V depending on the height h of lifting the load. The proposed device comprises an Ida: gchik block, a setpoint setting unit 2, an ingrization unit 3, a voltage source unit 4, a task setting and control unit 5, a summation unit 6, a root current sensor 7, a rectifier 8, a comparison block 9, an execution unit 10 and alarms, IIsoporeny sensor, sensor 12 track pulses, load weight sensor 13. Voltage (Jj at the output of block 2 sets the value of the permissible current exceeding, i.e., determines the setting of the operation of the protection device (Fig. 2). The voltage Us at the output of block 3 is proportional to degree H (; equilibrium lifting set | KI. Output voltages Unit 4 varies in proportion to the load cell load voltage. The greater the weight of the lifting vessel, the greater the voltage at the output of the load weight sensor and, accordingly, the voltage at the outputs of unit 4. The task setting and motion control device (type AKH or AZK) -5 is used for comm The output circuits of unit 4 are functioned as paths, and the outputs of unit 5 generate voltages Uj-Usn, shown in Fig. 2. The sum of all the voltages supplied to unit 6 gives a protective current diagram of the device. so that the voltage Ug at the output of block 8 exceeds the voltage Us at the output of block 6. In the initial position, the ultrasonic voltage at the output of block 3 is set equal to zero by the signal from the locking mask locking sensor 11. After loading the lifting vessel, the corresponding voltages are set at the output of the blocks 13 and 4. There are no Uj-Usn voltages at the output of block 6, since the floor switches of block 5 are open. The voltage at the output of block 6 is maximum. After starting the lifting machine, the path pulses 6 of the sensor 12 are fed to the input of the integrator 3, as a result of which its output voltage starts to linearly increase as a function of the path and subtracted from the resulting voltage of block 6. After the end of the acceleration period, the first test switch of block 5 is activated, the fourth input of unit 6 appears negative voltage Us, which leads to a decrease in voltage at the output of unit 6. Further, as the lifting machine moves, other storey switches and analogue to the previous case It continues to be formed protecting th current pattern unit. The voltage Ug at the output of block 6 in normal operation is always greater than the voltage Us at the output of block 8 and block 10 does not work. In the event of a lifting motor overload, the voltage at the output of block 8 will become greater than the voltage at the output of block 6, and block 10 will operate. In the empty vessel transfer mode, the process of forming a protective current diagram remains the same, only the voltages U4, Us-Usn decrease in proportion to the voltage decrease from the load weight sensor 13. Thus, the proposed device takes the imbalance of the 5th installation into account when forming the protective current diagram and also taken into account. the actual loading of the lifting vessel, which ultimately leads to an increase in the sensitivity and reliability of the protection. The proposed device easily implements on unified elements (for example, UBSR) and can find a wide application in lifting installations. Claims An apparatus for overcurrent protection of an electric drive of a lifting installation, comprising a current sensor cor, a summation unit, the output of which is functionally connected to an execution and alarm unit, characterized in that, in order to increase sensitivity and reliability, an additional sensor unit is included, including a sensor stopper, sensor track, impulse and load weight sensor, integration block, voltage source control unit, setpoint setting unit, task setting and controler control unit, rectifier and comparison unit, and you the stroke of the setting unit is connected to the first input of the summation unit, to the second input of which the outputs of the locking sensor and the track impulse sensor are connected via the integration unit, the load weight sensor connected to the input of the voltage source unit, the first output of which is directly connected to the third input unit the remaining outputs with the remaining inputs of the summation unit through the task and control unit, the output of the summation unit is connected to the first input of the comparator unit, to the second input of which It is connected via a rectifier through a current sensor core, and the output of the comparison unit is connected to the execution and alarm unit. Sources of information taken into account during the examination I. Kirichok Yu. G., Chermalykh V. M. Drive power shields of high power. M., Nedra, 1972, p. 261, fig. 912. 2. USSR author's certificate No. 674141, cl. H 02 H 3/08, 1977. Puz l U FIG. 2