SI23520A - Tester and the method of testing the direction of rotating and accuracy of stators winding connection of electric motor - Google Patents

Abstract

Tester and the method of testing the direction of rotating and accuracy of stators winding connection of electric motor with the help of hardware and suitable software electrically links individual pairs signals of neighborhood Halls sensors with two digital inputs of microprocessor. This electrical link can be carried out with the programmable logical device CPLD, or, if the processor is efficient enough, this connection or the choice of individual pairs of signals can be conducted by the microprocessor itself. The microprocessor then measures and calculates the ratio between time interval, when the digital signals of current Halls probes are equal throughout one period, and total time, during which the signals are digital equal or different, which is actually the period of the Hall probes signals.

Description

TESTER AND TESTING PROCEDURE OF DIRECTION OF DIRECTION AND CORRECTIVITY OF ELECTRIC STATOR Binding

TECHNICAL FIELD

Electrical engineering; measurements; electric motors

TECHNICAL PROBLEM

A technical problem solved by the object of the invention is the delayed (manual) movement of the tester along adjacent stator pairs, further measurement delay, further the size of the aperture required to manually move the tester, further uncertainty at angles 0 (rad) and π (rad), further the variability of results with respect to the position of the Hall probe on the stator tooth and also the disadvantages evident in electric motors where the number of poles of the electric motor p is comparable to the number of stator teeth with

BACKGROUND OF THE INVENTION

The existing tester (hereinafter referred to as "testerl") for the direction of rotation and correctness of the bonding is described in patent application DE102006050551 Al. It works with only two magnetic field detectors, in this case with two digital bipolar Hall sensors. The stator is excited during the test with a three-phase voltage that generates a rotating magnetic field. The testerl detects a magnetic field between two adjacent teeth of the stator of an electric motor, so the testerl is suitable for all motors, both rotary and linear, asynchronous and synchronous machines. Since only two magnetic field sensors are used, the movement of the saws throughout the stator requires verification of the direction of rotation and the correct binding of the entire stator of the electric motor. The operation of the testers is based on a comparison of the signals of the two Hall sensors by determining the digital value of the 2nd Hall probe when the signal of the 1st Hall probe is changed from a digital value of zero (0) to a value of one (1): if the value For example, the 2nd Hall probe is 0, for example, the direction of rotation is to the left (+), but if the value of the 2nd Hall probe is 1 then the direction of rotation is to the right (-). Testerl reports the status of the stator on the tested two teeth through five LEDs. The first two, located at each tooth tested, indicate whether the individual stator tooth is magnetically active at all, a prerequisite for the tester to function at all. If the direction of rotation is +, LED3 is activated, and if the direction of rotation is LED5. LED4, however, reports any measurement invalidation that may occur at electrical angles near 7r [rad] or 0 [rad].

The disadvantages of the saws are the following:

The tester must be moved manually over all adjacent stator pairs

The measurement may be time consuming and not suitable for larger series

The worker can move the tester too fast, which degrades the reliability of the tester

For smaller engines, the opening provided for the rotor may be too small for the arm and the saw

At electric angles near pi [rad] or 0 [rad], the tester is unreliable

The result may be different depending on the position of the Hall probe on the stator tooth

The imperfections of the saw blades are particularly pronounced for electric motors where the number of poles of the electric motor p is comparable to the number of teeth of the stator z- This is so-called direct drive electric motors where the number of teeth is comparable to the number of poles, for example, the number of teeth z = 12 and the number of poles so p = \ 0.

DESCRIPTION OF THE NEW SOLUTION

The technical problem presented above is solved by the tester and the procedure for testing the direction of rotation and correctness of the binding of the stator of the electric motor (the tester of the present invention is hereinafter referred to as "tester2"),

Tester2 eliminates all the shortcomings of the tester. There are as many magnetic field sensors present on the tester as there are the number of teeth of the stator of the electric motor, so the tester does not need to move during the measurement. Just like the tester, Tester2 is suitable for use with all types of electric motors, both rotary and linear induction and synchronous machines.

Tester2 electrically connects individual pairs of signals from adjacent Hall sensors to two digital microprocessor inputs using hardware and software. This electrical connection can be made using the CPLD programmable logic circuit, but if the processor is sufficiently powerful, the microprocessor performs this connection, or the selection of individual signal pairs. The microprocessor then measures and calculates the ratio of the times when the digital signals of the selected two Hall probes in one period are the same and the total time that the signals are digitally the same or different, which is essentially the period of the Hall probe signals.

For greater accuracy, the measurement can take several periods, in our case it is a 10 period, the period being defined as the time between two changes of the digital signal value from 0 to 1 or from 1 to 0. The point is that when transients of a digital signal for example, the first of the selected Hall probe pair from 0 to 1 checks the digital value of the second of the selected Hall probe pair. If the value is 0, it rotates in one direction, and if the value is 1, rotates in the other direction. Again, for the sake of greater reliability, this is a longer period of Hall probe signals, in our case this is a 10 period. For electric angles very close to 7t [rad] or 0 [radj], the tester is also unreliable, but this unreliability is taken into account by the Tester2 software in its diagnostic software. The data on electric angles and direction of rotation of all signal pairs 1 through Hall sensors are stored by Tester2 in the database and based on these data, Tester2 software decides whether the stator of the electric motor is properly connected and rotates in the right direction (microprocessor based on calculates the sum of the electric angles between the adjacent teeth. If all three of the conditions listed below are satisfied, the stator is connected OK). The basic diagnostics, which takes place in the Tester itself2, are based on three data:

The sum of the electric angles must be close to * 7t [rad],

The individual electric angles must be within certain limits [amin ... amax],

The direction of rotation that can be (reliably) determined must all be in the same direction.

For example, the stator of a concrete motor has twelve teeth z = 12 and is connected so that it has ten poles p = 10. The sum of all twelve electric angles should be around 10 * 7t [rad], but tolerances are allowed from 9.80 * 7i [rad], to 10.2 * 7r [rad]. The individual electric angles must be between 0.69 * 7i [rad] to 0.96 * You [rad], which are amine and amax. These values are determined on a case by case basis for engines. The direction of rotation is determined reliably if, in the particular case of determining the direction between two teeth out of ten attempts at least nine times, or in most experiments, it determines the same direction of rotation and that for all pairs of signals, when it can reliably determine the direction of rotation, these directions are the same.

The basic diagnostics that take place inside Tester2 only tell you whether or not the stator is OK. Tester2 also sends information on the number of teeth, electric angles and direction of rotation via the communication channel to the parent computer, where advanced diagnostics can be performed, which can also tell in the event of a fault what is wrong with the stator of the electric motor (this happens in the parent computer, using statistical methods, artificial neural networks, or the like.

The following is an object of the invention by way of a sketch, the sketch being part of the patent application and the sketch showing an example of Tester 2 for rotary engines. z = l2, p = 10.

Figure 1 shows the tester circuit 1, microprocessor 2, Hall probes 3, CPLD - programmable digital circuit 4, internal or basic diagnostics LED 5, connector for powering the tester and communication with the parent computer 6, the stator yoke of the electric motor 7 and the stator winding coils of the electric motor 8.

Claims (6)

1. A test of the direction of rotation and the correctness of the binding of an electric motor stator comprising at least one pair of magnetic field sensors, preferably Hall sensors, characterized in that the tester comprises as many magnetic field sensors as the number of teeth of the electric motor stator. The tester according to claim 1, characterized in that the tester selects individual pairs of signals transmitted by magnetic field sensors and measures electrical angles between adjacent teeth of the stator. A tester according to claim 1, characterized in that it electrically connects individual pairs of signals from adjacent Hall sensors to two digital inputs of the microprocessor, the connection being preferably made by means of a programmable CPLD logic circuit, whereupon the ratio of time is measured and calculated , when the digital signals of the two Hall probes selected in one period are the same and the total time the signals are digitally identical or different. A method of testing the direction of rotation and the correctness of the coupling of an electric motor stator, characterized in that the device according to any of the preceding claims selects at least two Hall probe pairs, furthermore, in the case of digital signal transitions, for example, the first of the selected Hall probe pair from 0 to 1 checks the digital value of the second of the selected two Hall probes, further revealing that at 0 the value of the motor rotates in one direction and at the value 1 in the other direction. Method according to claim 4, characterized in that the measurement takes place over a period of time, preferably 10 periods. Method according to claims 4 or 5, characterized in that the stator binding is correct, in so far as it is satisfied that the sum of the measured electric angles is close to p (number / o / s) * K [rad], further that individual electric angles within the boundaries between amine and amax, preferably between 0.69 * 7t [rad] to 0.96 * 7i [rad], and finally that the direction of rotation which is determinable is in the same direction.