DE3317871A1 - Method for implementing fault-dependent control of electrical drive motors, and a circuitry arrangement for implementing the method - Google Patents

Abstract

The invention relates to a method for implementing fault-dependent control of electrical drive motors of optionally interconnected fluid kinetic machines such as pumps, fans or the like, in conjunction with a load-independent rotational speed control, and a circuitry arrangement for implementing the method. According to the invention, control is effected by 1) checking sequentially whether a) there is a fault at one of the drive motors of the fluid kinetic machines, b) in the case of a fault the control device assigned to the drive motor of the fluid kinetic machine is faulty, c) in the case of a fault on a drive motor, but with the control device serviceable, there is an overload current applied to the drive motor, d) in the case of an overload current being applied to the drive motor, the latter is switched off or, if there is no overload current, the drive motor, while the control device is faulty, is connected directly to the grid and that 2) in the case of a subsequent fault of the fluid kinetic machine, the control loop of a further interconnected fluid kinetic machine being checked and this machine being started up, and 3) simultaneously at least the phase angle of the drive motor of the operational fluid kinetic machine, upon a load change of the fluid kinetic machine, being changed so as to keep constant the rotational speed of the fluid kinetic machine. The circuit for implementing the method comprises a control device 4, which ... a motor protection device 5 for the connection ... Original abstract incomplete.

Description

The invention relates to a method of implementation an accident-dependent control of electric drive motors, possibly connected in a network Flow machines such as pumps, fans or the like. In connection with a load-independent speed control and a Circuit arrangement for carrying out the method.

At z. B. pumps with AC motors commonly used in heating systems are the facilities designed to monitor the function of the pumps so that in the event of a fault, the pump is switched off electrically is separated from the AC voltage network. Since this significantly impairs or even affects the delivery of the fluid is interrupted, z. B. Significant impairments in the heat supply occur in cold spells, with the risk of consequential damage. Another disadvantage of these known pumps with AC motors consists in the fact that with the usual constant phase angle of the applied to the motor Voltage when the load torque increases due to changes in the differential pressure between pump input and Pump output as a result of z. B. a desired increase in the fluid delivery due to the connection of further Heat consumers, the voltage fed back from the motor is reduced with the result that the speed of the Motor and thus also the delivery rate of the pump decreases.

The object of the invention is to provide a method and a circuit arrangement for carrying out the method to show, when used, the disadvantages of the known devices described are avoided.

According to the invention, the object is achieved in that

1) it is sequentially checked whether *

a) there is a malfunction in one of the drive motors of the turbomachines,

b) in the event of a malfunction, that assigned to the drive motor of the turbomachine Control device is disturbed,

c) in the event of a fault in a drive motor but with the control unit intact Overcurrent is applied to the drive motor,

d) if an overcurrent is applied to the drive motor, it is switched off or at If there is no overcurrent, the drive motor is connected directly to the mains if the control unit is faulty and that in the event of a disturbance in the flow machine that then follows, the control loop another turbomachine connected in the network and put it into operation is taken and

2) simultaneously at least the phase control of the drive motor of the turbo machine in operation in the event of a change in load of the turbomachine is changed to such an extent that the speed the flow machine remains constant.

According to a further feature of the invention, a control device is provided that a motor protection for connecting the

rs-

Has drive motors of the flow machines and a regulating and control unit, by means of which the fault check the drive motors and turbomachines and the phase control can be carried out.

■ -_ -7 * -

Further features of the invention are set out in the subclaims and in the following with reference to the circuit shown schematically in the drawings explained.

It shows

Fig. 1 shows an embodiment of the invention

Arrangement with an automatic control device for two pumps as a network plan

Fig. 2 shows the functional sequence of the automatic

Control device in the event of a fault in a block diagram

3a shows a schematic representation of the voltage curve up to 3d during each one period

Fig. 4 is a block diagram of the invention

Phase control with speed compensation

5 shows an embodiment of the circuit in a section.

In Fig. 1, a circuit arrangement 31 for two drive motors 6 of, for. B. two pumps 7, 8 shown. The control of the drive motors 6 takes place via a control device 4, which is connected to the Network 3 is connected. In the control device 4 there is a regulating and control unit 9 that controls the individual Carries out test and control processes. The drive motors 6 are connected once directly via the control and Control unit 9 and on the other hand via mains connection lines 14, 15 arranged as a bypass. For switching on the drive motors 6 is a z. B. designed as a contactor switching element 16, 17, 18, 19 is provided.

The function of the accident test in the circuit arrangement 31 is shown schematically in the block diagram according to FIG. The general activation and deactivation of the Turbomachines 7, 8 take place via a timer 13, by means of which the commissioning and decommissioning of the individual flow machines 7, 8 can take place within fixed time periods. If «-first the turbo machine 7 is to be put into operation, it is first checked whether there is a fault. Isn't this the one If so, it is checked whether the control device 4 is disturbed. If this is not the case, an overcurrent is checked. If this is not the case, the turbomachine 7 is put into operation. If there is an overcurrent, the Turbomachine 7 reported as malfunctioning, whereupon the regulating and control unit 9 opens the control loop of the second Turbo machine 8 checked. As long as this turbo machine 8 is fault-free, it is fully operational taken. In the event of a fault in the turbomachine 8 as well, the turbomachines 7, 8 would finally be disconnected from the network be switched off. If only the regulating and 'control unit 9 is disturbed, the mains voltage supply switched to the network connection lines 14, 15.

As shown in FIGS. 3a to 3d, control signals are derived from the sinusoidal mains voltage, which occur in the magnitude of the phase control angle T. With ideal conditions, the output voltage would qualitatively correspond to the illustration in FIG. 3c. In fact, however, there are feed-backs 30 from the respective drive motor 6, which cause a curve shape as shown in FIG. 3d. In the case of AC motors 6 operated with phase control, these operate in generator mode during the break. The generator voltage thus applied to the output terminals of the motor can be measured via an electrical circuit with voltage dividers, potential separators, rectification and the like and used in a suitable form to change the lead angle. By moving the lead angle f forward, COPY

despite the increased load torque at which the voltage fed back by the drive motor 6 is lower than in the normal case, close to constant electrical operating conditions can be achieved. The resulting drop in speed can then corrected by the phase control circuit 1 by bringing the phase control angle f forward will. A block diagram of the phase control is shown in FIG. Between the network 3 and the Drive motor 6 is an output stage unit 21 and a measuring circuit 10. The measuring circuit 10 is with a Voltage matching circuit 11 connected, which in turn is connected to the phase angle interference circuit 1 in connection. The phase control interference circuit 1 is also connected to the output stage unit 21. An adjustment device 2 is connected to the phase control circuit 1 and is used to set the dependent of the pressure and temperature in the fluid, the setpoint value of the phase control to be determined.

In FIG. 5, a section of the circuit in the regulating and control unit 9 is shown. The power amplifier unit 21 has an arrangement of resistors 22, diodes 24 and an operational amplifier 23, the Output stage unit 21 is in operative connection with setting device 2 and is connected to a CMOS analog switch 12 connected. This CMOS analog switch 12 is also connected to the measuring circuit 10, next to Resistors and a CMOS analog switch 12 has potential separation circuits 20. At the exit of the former CMOS analog switch 12 is the voltage adjustment circuit 11 arranged, the two operating voltage connection points 28, 29 with positive and negative Operating voltage is applied. The voltage matching circuit 11 has a plurality of resistors 22 and two operational amplifiers 21 and two capacitors 25.

Claims (12)

DR.-ING. J. SCHMIDT-BQGATZICV ...- ".. *> - Ά tentanwal EUROPEAN PATENT ATTORNC Note: Karl Müller / 2351 TrappenkamD Anton Einhof f / 5000 Köln 'D-2100 Hamburg 90 (Harburg) Karsten Allderding 2362 Wahlstedt scHL ° ssM ° HLEN DA MM TELEPHONE: O4O - 7 7 77 Description: Procedure for carrying out τ ε l ε χ: 217795 ι ν tec d an accident-dependent control of electrical drive MEA 83 14 motors and circuit arrangement file no .. for carrying out the procedure YOUR CHARACTER i May 16, 1983 / ti. DATE: PATENT CLAIMS 1.! A method for carrying out an accident-dependent ^ -— J control of electric drive motors of optionally connected flow machines such as pumps, fans or the like in connection with a load-independent speed control, characterized in that 1) it is checked sequentially whether a) there is a malfunction in one of the drive motors of the turbomachines, b) in the event of a fault, the one assigned to the drive motor of the turbomachine Control device is disturbed, c) in the event of a fault in a drive motor but with the control unit intact an overcurrent is applied to the drive motor, d) if there is an overcurrent on the drive motor, it is switched off or at If there is no overcurrent of the drive motor in the event of a faulty control unit, it is directly connected to the mains is connected and that in the event of a malfunction of the turbomachine that then follows Control loop of another turbomachine * connected in the network - checked and this is put into operation and 2) at the same time the phase control of the drive motor of the turbo machine in operation a load change of the turbo engine is changed to such an extent that the speed of the turbo engine remains constant 2. The method according to claim 1, characterized in that in the event of a fault in the drive motor one of several Turbo machines the control loop of another turbo machine is checked. 3. The method according to claim 1 and 2, characterized in that in the event of a fault in one of the in the network switched flow machines, it is first sequentially checked whether one of the other flow machines is fault-free, which is then put into operation. 4. The method according to claim 1, characterized in that in the event of a drop in rotational speed of the turbo machine, the phase control angle is brought forward. 5. The method according to claim 1 and 4, characterized in that the generator voltage to keep the speed constant measured and when they change by varying the load torque of the phase control angle is changed. ^T COPY 6. Circuit for performing the method according to claim 1 to 5, characterized by a control device (4), the motor protection (5) for connecting the drive motors (6) of the flow machines (7, 8) and has a regulating and control unit (9) by means of which the fault check of the drive motors (6) and Flow machines (7, 8) and the phase control can be carried out. 7. A circuit according to claim 6, characterized in that each drive motor (6) has a potential separation circuit, Voltage divider or the like. Trained measuring circuit (10) is assigned. 8. Circuit according to claim 6 and 7, characterized in that the measuring circuit (10) has a voltage adapter circuit (11) for processing the measured values of the motor voltage to a specified measuring range with the Phase control (1) is connected .. 9. Circuit according to claim 6 to 8, characterized in that the phase control circuit (1) by means of an adjusting device (2) to one of the target temperature or the target differential pressure of the Fluid-dependent setpoint is adjustable. "10. Circuit according to claim 6 to 9, characterized in that that the measuring circuit (10) is in operative connection with the setting device (2) Analog circuit element (12) is connected to the voltage adjustment circuit (11). 11. Circuit according to claim 10, characterized in that that the analog circuit element (12) is designed as a CMOS switch. 12. Circuit according to claim 6 to λ}, characterized in that the drive motors (6) of the turbomachines (7, 8) are arranged in a cascade connection.