SU1587151A1 - Method of monitoring parameters of excavator electric drive - Google Patents

Abstract

The invention relates to the measurement of the performance characteristics of mining machines and is intended to quickly determine the failure of the motor of an excavator drive (EP) during its operation. The purpose of the invention is to increase the reliability of control of electronic signature. For this purpose, the level of arcing of the electric motor (ED) is measured and its average value is determined over the time interval ΔT. In this case, the variable component of the core current of the ED is rectified in the frequency range from F 1 = PN / 60 Hz to F 2 = 50 kHz, where P is the number of pole pairs

N is the speed of ED. The specified value is filtered and integrated within one revolution of the box. The frequency range is chosen in the range of 30-50 kHz, and the interval ΔT is chosen to be 1-3 s. Then, the nominal values of the spark levels of the collector of the ED are set when the EP is operated according to the external characteristic in the zone characterized by a change in the magnitude of the deceleration of the ED core rotation at least 3-5 times, and in the zone characterized by the change in the rotation speed of the engine core in the range of 0-0.05 idle speed. The average speed value measured over a given time interval ΔT is compared with the nominal values of the spark levels set for the indicated zones and, based on the results of the comparison, a malfunctioning DE is judged. 3 hp ff, 2 ill.

Description

the rotational speeds of the engine core in the range from zero to 0.05 times the idling rate, compare the average value of the motor collector sparking measured at the interval At with the nominal values of the spark level specified for the specified zones and comparing the results of the motor failure.

The method includes the following main 1

operations.

The mode of operation of the actuator is determined on the external electromechanical characteristic, for example, by the position of the motor control command device. Measure the speed. Rotation of the drive shaft P | with his work on the external characteristics. The current in the electric motor's main circuit is measured when the electric drive is operated on an external characteristic. At discrete time intervals, the deceleration on the shaft of an electric drive operating on an external characteristic is determined by the formula;

nti H-1 - p ti / hh,

ati - r: rv-;

where nti, nti + 1 are the rotational speeds of the drive shaft at times tj, ti 4-1:

ti + 1-ti const is the differentiation interval for the rotational speed of the drive shaft.

The moment of passing the breakpoint of the external excavator speed characteristic is determined: ti + 1 - n ti o g- / t + i JL N (2) V -ti /

h

ti + 1-ti tj-bi-tj

Measured in the fracture zone, speed characteristic, actual rotation speed of the electric drive shaft. Measured in the fracture zone, speed characteristic, the actual current in the electrical circuit of the electric motor 1. Measured in the fracture velocity range, the level of the variable component of the core current of the electric motor 1 / 1gate T Determine the area of the moment of the speed characteristic of the sign, if

About P1 0,05p XX / C

0, 0.95

or

About P1 0.5xxx1

1, m 1 | T. where Pxx is the rotation speed of the motor shaft at a current in the core circuit, close to zero (

idle speed);

i I nom - actual and nominal stopping currents.

Measured in the area of the stopping moment of the speed characteristic, the level of the variable component of the electric current of the motor 5 Set the averaging interval At and determine the average value of the levels of the variable components of the electric current of the electric motor in the zones of fracture and the stopping moment of the speed characteristic

Ik

/ l $ ldt

Ty tH

| f

tK - tH

tK.

/I|.i dt

(five)

(6)

tk

tK -tH

tH At-integration interval:

tH, tK are the start and end points of the integration.

The permissible levels of the variable component of the crust current in the break zones of the speed characteristic 1 dop and stopping moment T dop are set. Determine the fault signal of the drive during its operation sign, if

p (0, 95) piom (7)

or

l (0.9f 0.95) 1 Com, (8)

or

nti 0,05PHH1 / dC

or

or

1 (0.9 g 0.95)

nti 0.05xxx

1 (1.05f1.1)

7i -.ti | f, - 1dop,

},

(ten)

(eleven)

or

  R

1dop, (42)

where PCM.I nom is the nominal speed of rotation of the shaft and the current of the electric motor's crustal circuit in the break zone the speed characteristic;

Tf, Tf are the average values of the variable component of the main current of the electric motor in the zones of the break and the stopping moment of the speed characteristic;

1dop, Tdop are the permissible levels of the alternating component of the main current in the break zones of the speed characteristic and the stopping moment.

When a DC collector motor is in operation, a variable component arises in the core circuit.

which, in turn, contains a harmonic component with the fundamental frequency fi pn / 60, where p is the number of pole pairs; n is the number of cores of the core: harmonic pulsating component with the fundamental frequency f2 zn / 60, where Z is the number of teeth of the core; Sarmonic component with a collector frequency f3 kn / 60, where k is the number of collector teeth; harmonic, due to the voltage at the point of rupture of the contact of switched sections f4 30 kHz.

The change in the listed components of the short-circuit current during one revolution of the core characterizes the effect on these variables of the corresponding motor faults (deviations from nominal values), which is a frequency that characterizes the state of the magnetic circuit of the motor (excitation windings, state of the magneto-drive and its elements), F characterizes the state of motor bearings, brush holders, brushes, manifold, etc. .

Consequently, the integral value of the rectified variable component of the electric motor core current in the frequency range fi f in the integration interval D t (for example, during one revolution of the core) characterizes the state of the electric motor.

To determine the inadmissible level of a variable component, you can use the following technique. In bench tests of a serviceable motor, the nominal level of the variable component of the crust current in the established areas of the operating parameters of the electric motor is determined — in the break zone of the speed characteristic and in the stop torque zone. The unacceptable level of the variable component is determined by increasing the nominal level in accordance with recommendations, for example, according to GOST 19705-81 and GOST 183-74.

Measuring the variable component of the motor's crust current in a wide range of fi-f4 can detect almost all types of faults in the motor, however, to accumulate reliable data to make a decision about the fault, the integration period of the variable component should be significantly increased compared with the case when on one of the components, i.e. in determining faults motor limited

the number of species takes less time than in determining faults of all kinds (with the same significance level of indicators). Therefore, the determination of a motor malfunction in the frequency range f4 30-50 kHz reduces the delay in generating a malfunction signal, taking into account the main types of engine malfunctions; wear of bearings, brushes, manifold, failure of the brush holder,

10 Thus, the determination of the level of the variable component of the crustal current in the zones of fracture and stopping torque of the high-speed excavator characteristic allows timely detection

15 motor malfunction and prevent their development to a level that is controlled in a known manner. This reduces the duration and cost of repairing an excavator drive, which ultimately

20 causes an increase in the operational performance of excavators.

A variable component extraction node 1 is connected by an output to an amplifier 2, the output of which is connected in series to an input of a calculator 3 via a serially connected band-pass filter 4, an amplitude detector 5 and a low-pass filter 6 6 and an electric drive control system 8

30 are connected to the inputs of the calculator 3, the output of which is connected to the output indicator 9. The inputs of the node 1 and the calculator 3 are connected to the core circuit of the electric motor 10, the bark of which is mechanically connected to the sensor 7.

35The device operates as follows.

. In the process of excavation to the input of node 1 and the output of sensor 7 receives signals proportional to the total current of the core circuit

0 1 | and the engine rpm. From the output; the evil 1 signal of the variable component 1f is received from the driver and / 1 driver 2, then passes through the bandpass filter 4, is detected by an amplitude detector 5, filtered

5 by the low-pass filter 6 and is fed to the corresponding input of the calculator 3. Under the conditions (2), the calculator generates a signal sign А-1. characterizing the operation of the electric drive in the fracture zone

0 speed characteristics. In this zone, the calculator 3 determines the current average values of Tf (5), pf, If and generates a fault signal (unacceptable deviation of parameters) of the electric drive sign B 1 when the condition (7) or (8) or (11) is fulfilled .

If the electric drive operates in the area of the stopping torque, then the calculator 3 generates a sign when the condition (3) or (4) is fulfilled. In this case, fg, 6) is determined and the signal of the drive malfunction sign is generated when condition (9) or (10) is fulfilled. or (12). The sign signal is indicated by the output indicator 9 and can be used to automatically turn off the drive.

Thus, the proposed method provides control of the state of the electric drive in the event of the occurrence of various kinds of faults in the electrical and mechanical parts of the electric motor, and the fault signal is generated with a minimum delay, eliminating the development of a fault during the operation of an excavator.

Claims (4)

The use of the method allows to increase the operational performance of the excavator by reducing the duration of repairs with timely detection of malfunctions. Claim 1. Method of monitoring parameters of an excavator drive according to author. No. 1146369, characterized in that. that, in order to increase the reliability of the control of the electric drive, the level of arcing of the motor collector is additionally measured, its average value is determined at the interval A t, the nominal values of the motor collector arcing levels are set when the drive operates on the external characteristic in an area characterized by a change in the magnitude of rotation slowing engine core no less than 3-5 times, and in the zone characterized by a change in the speed of rotation of the engine core in the range from zero to 0.05 idle speed, 10 Niwa average value measured at the level of arcing interval At collector motor with predetermined zones for said nominal values arcing levels and comparing the results 15 fails the motor, 2. A method according to claim 1, characterized in that the arcing level of the motor collector is determined by rectifying the variable component of the core 20 current of the electric motor in the frequency range from fi pn / 60 Hz to kHz, subsequent filtration of the specified value and its integration during one revolution of the core, where p is the number of pole pairs; n is the number of revolutions of the electric motor. 3. The method according to claim 2. wherein the frequency range is selected within 3Q-50 kHz. 4. The method according to paragraphs. 1 and 2, about tl and h 3 y u and y30 so that the interval for determining the average rectified and filtered values variable core current component electric motor is 1--3 s. AT 5 X I, V ( at I in 1shp b FIG. 2