DE102004045570A1 - Method for a V-belt malfunction detection - Google Patents

Abstract

In a method for a V-belt malfunction detection in a standard inverter-driven asynchronous motor 1 for driving a rotary heat exchanger is a periodic reparameterization test parameters of the inverter 8 for a start of the induction motor 1 to a target speed, monitoring the overturning moment and a determination that the V-belt no forces transmits the rotor, if the overturning moment is not reached, or a statement that the rotor of the rotary heat exchanger is driven via the V-belt, provided that the overturning moment is exceeded.

Description

The The invention relates to a method for a V-belt malfunction detection such as a V-belt tear, a V-belt or the like in converter-driven asynchronous motors for driving rotary heat exchangers.

For the controller Inverter-driven asynchronous motors in which the speed of a rotor is lower is as the rotational speed of the rotating magnetic field, are a variety known and proven by regulations. Such asynchronous motors are also regularly used to drive rotary heat exchangers used, wherein a power transmission from the asynchronous motor mostly via a Speed-reducing transmission initially on an output shaft and from there on a V-belt on the rotor of the rotary heat exchanger, its maximum Diameter regularly for another Speed reduction is wrapped by the V-belt.

There such rotary heat exchangers in, for example, air conditioning systems, regularly away from central monitoring stations Use find the power transmission via the V-belt must be monitored separately. As typical malfunctions here are the jumping off of the V-belt and in particular to call a V-belt crack. It turns the problem that even with vector-controlled frequency converters, the above a precise phase current measurement and evaluation, the measured current difference, in particular that of the effective current component, between an idle, synonymous with a V-belt crack or a broken V-belt, and a load case at normal operating conditions is not enough for a safe detection of the V-belt malfunction. Reason lies this is because the load through the rotor of the rotary heat exchanger for the Drive in conjunction with the mentioned gear ratios no significant, additional Represents load.

For monitoring The rotation of the rotor is therefore usually used sensors likewise in manifold embodiments known and proven are. Inductive, capacitive and magnetic working are used Systems that all have in common is that they are centralized Control center must be wired. Accordingly uncertain is the monitoring, because in case of cable break, failure of one or more sensors u.a. the feedback from the rotary heat exchanger can be faulty to a central office and thus is not sure.

In front In this technical background, it is the object of the invention to a method for a to provide such malfunction detection that without immediate monitoring for example, by sensors detecting the rotation of the rotor a rotary heat exchanger allows.

Is solved this technical problem according to the method according to claim 1 for V-belt malfunction detection in inverter-driven asynchronous motors for driving rotary heat exchangers by the method steps of the periodic reparameterization of the Inverter for one Startup of the asynchronous motor, the monitoring of the overturning moment same and the finding that the V-belt no forces on transmits the rotor, if the overturning moment is not reached or exceeded or the Finding that over the V-belt is driven by the rotor of the rotary heat exchanger, if the overturning moment is exceeded becomes.

It is during normal operation, for a short time, the drive of the rotary heat exchanger shuts down, preferably to a standstill of the rotor, and then takes place restart the asynchronous motor, which monitors startup becomes.

The Method according to the invention makes use of the fact that the Speed of an asynchronous motor with increasing load up to the roundabouts of the overturning moment, the maximum torque, that one with rated frequency and rated voltage operated alternator with slow increase can reach the load, initially only very little decreases. It is therefore in an idle case, synonymous with a broken or cracked V-belt, the asynchronous motor a start to its setpoint speed without reaching or exceeding of the overturning moment. The engine is very far in the field weakening area operated, in which the power consumption is very low.

In a load case, if over the V-belt is driven by the rotor of the rotary heat exchanger, the current increases considerably and the overturning moment is reached or exceeded, along with a torque drop and a reduction of Rotation speed. In such a case, it is found that the V-belt sits correctly.

It It is understood that when determining that over the V-belt no more forces transferred to the rotor immediately, an error message is issued and the asynchronous motor is switched off.

The monitoring of whether the tipping moment is achieved or not, is advantageously carried out by a current measurements, preferably hochge Nau at a shunt occurs, the measurement of two phases will be sufficient as a rule, from which two measurements then the current of the third phase is calculated.

Such is relatively easy to do, because the current of the asynchronous motors used between 8 A and 10 A are not present and a short circuit current is not occurs.

Also if the periodic reparameterization of the inverter is at a distance after a few minutes, it has proved useful if a startup of the asynchronous motor can also be triggered manually, for example, if irregularities suspected become.

Corresponding is the technical explained above Problem also of a converter-driven asynchronous motor, the over a transmission and a V-belt a rotor of a rotary heat exchanger drives, solved by a regulation, which periodically reparameterization of the inverter for a start-up of the asynchronous motor, and by a measuring device for one Measurement of the current absorbed by the asynchronous motor, by a Evaluation device, which consists of the measurement of the current on the overturning moment closes and determines if the V-belt does not transmit any forces to the rotor, provided the tipping moment is not reached or exceeded or determines, whether over the V-belt the rotor of the rotary heat exchanger is driven, if the overturning moment is exceeded becomes.

there is further provided that the measuring device, the power of two Phases and that the evaluator measures the current of the third Phase calculated.

Naturally, in in the case where the V-belt does not transmit forces to the rotor, such central monitoring be reported.

The method and the device according to the invention are explained in more detail with reference to a flow chart in the drawing, in which the only 1 shows the control of an asynchronous motor.

The actual power supply of an asynchronous motor 1 takes place in one or three phases from a network 2 via a filter module 3 and a mains choke 4 towards a charging circuit 5 , Next delivers a rectifier 6 including the voltage for a switching power supply 7 for the power supply of the entire periphery. A parameterizable inverter 8th then controls via a filter 9 the asynchronous motor 1 which is essentially the conventional operation of an asynchronous motor 1 equivalent.

Between the inverter 8th and the filter 9 In the exemplary embodiment, a current measurement is carried out by means of a measuring device 10 , in particular only two phases. If necessary, a third phase can be performed by an evaluation device 11 calculated from the current measurement of the other two phases. The current measurement itself is preferably carried out on a shunt resistor, a shunt, and can be highly accurate.

The measured value acquisition or evaluation device 11 stands with a motor and application controller 12 in connection, through which periodically the inverter 8th for a startup of the asynchronous motor 1 via a modulation 13 and driver stage 14 is parametrized, so that the asynchronous motor 1 makes a start under load. By feedback via the measuring device 10 and the fair value registration 11 can this or the motor and application controller 12 recognize as an evaluation, whether at the start of the V-belt no longer transfers forces to the rotor, in which it is determined that the overturning moment is not reached or exceeded. If this overturning moment is exceeded, it is clear that the rotor of the rotary heat exchanger continues to be correctly driven via the V-belt.

For a corresponding display of an error message or data storage are appropriate displays 15 or other mass storage available.

For programming the evaluation device 12 is an input and output unit 16 ultimately provided, among other things, a manual triggering a test startup can also be triggered.

1

asynchronous

2

network

3

filter module

4

Line reactor

5

charging circuit

6

rectifier

7

Switching Power Supply

8th

inverter

9

filter

10

measuring device

11

evaluation

12

Engine- and

Application control,

evaluation

13

modulation stage

14

driver stage

15

display

16

One- and output unit

Claims (7)

Method for a V-belt malfunction detection in converter-driven asynchronous motors for driving rotary heat exchangers, characterized by the method steps - the periodic reparameterization of the converter ( 8th ) for the one start of the asynchronous motor ( 1 ), - the monitoring of the overturning moment and - the fact that the V-belt does not transmit any forces to the rotor unless the overturning moment is reached or exceeded or - the determination that the rotor of the rotary heat exchanger is driven by the V-belt, if the overturning moment is exceeded becomes. Method according to claim 1, characterized in that that monitoring done by current measurements. Method according to one or more of the preceding Claims, characterized in that the current of two phases is measured and the current of the third phase is calculated. Method according to one or more of the preceding Claims, characterized in that the current measurement at a shunt he follows. Method according to one or more of the preceding claims, characterized in that a starting of the asynchronous motor ( 1 ) is manually triggered. A rotary heat exchanger driven by a converter-driven asynchronous motor via a gearbox and a V-belt, characterized by - a control ( 12 ), which is a periodic reparameterization of the inverter ( 8th ) for a start-up of the asynchronous motor ( 1 ), - a measuring device ( 10 ) for a measurement of the asynchronous motor ( 1 ) recorded current, - an evaluation device ( 11 ), which concludes from the measurement of the current on the overturning moment and - determines whether the belt transmits no forces to the rotor, if the overturning moment is not reached or exceeded or - determines whether the rotor of the rotary heat exchanger is driven by the V-belt, provided that the overturning moment is exceeded. Rotary heat exchanger according to claim 6, characterized in that the measuring device ( 10 ) measures the current of two phases and that the evaluation device ( 11 ) calculates the current of the third phase.