JPH04310883A - Apparatus for measuring frequency characteristics of stepping motor - Google Patents

Abstract

PURPOSE:To instantaneously measure the characteristics of the max. self-exciting frequency and the max. response frequency with high accuracy by providing a drive part changing the repeated frequency of the drive pulse of a stepping motor to be measured and a control part detecting and outputting the average value or effective value of the drive current of the stepping motor corresponding to the frequency. CONSTITUTION:A stepping motor 1 to be measured, a control part 2, a drive part 3 and a DC power supply 4 are provided. When the repeated frequency of the drive pulse applied to the motor 1 is gradually raised, the DC current A flowing to a resistor 4a is reduced by the effect of the inductance of the winding of the motor 1. When the DC current A reaches a certain point f2, the motor 1 becomes out-of-phase conditions wherein the motor can not rotate in response to the repeated frequency and the inductance of the winding of the motor suddenly lowers and the current A suddenly increases. When the repeated frequency of the pulse is gradually lowered, the motor again starts normal rotation at a certain point f1 and current characteristics show hysteresis characteristics. The point f1 is the max. self-starting frequency and the point f2 is the max. response frequency.

Description

[Detailed description of the invention]

0010

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the characteristics of a stepping motor.

0002

[Prior Art] Stepping motors have good responsiveness in starting, stopping, forward and reverse rotation, can obtain accurate rotation angles, and can self-maintain this rotation angle. Widely used in equipment. Therefore, measuring the characteristics of this stepping motor is
This is necessary from the standpoint of product testing of stepping motors.

0003

[Problem to be solved by the invention] Among the characteristics of a stepping motor, it is defined as the maximum frequency in the region where it can start, stop, and reverse in synchronization with an externally applied signal (self-starting region). Maximum self-starting frequency (f1)
When the frequency of a stepping motor that is running synchronously is gradually increased (or when the load torque is gradually increased), the maximum frequency in the region where the stepping motor can respond without losing synchronization (through region) The maximum response frequency (f2) defined as Therefore, it is inconvenient to measure and it is not possible to obtain high-precision measurement results in a short time.Therefore, it is applied to stepping motor production lines to quickly and accurately measure the maximum self-starting frequency ( A technique for measuring the maximum response frequency (f1) and the maximum response frequency (f2) has not yet been proposed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a frequency characteristic measuring device for a stepping motor that can instantly and accurately measure the characteristics of the maximum self-starting frequency and the maximum response frequency.

[0005]

[Means for Solving the Problems] In order to achieve this object, a stepping motor frequency characteristic measuring device according to the present invention includes a driving means for changing the repetition frequency of a driving pulse of a stepping motor to be measured, and a driving means for changing the repetition frequency of a driving pulse of a stepping motor to be measured. A configuration comprising: a control means for detecting an average value or an effective value of the drive current of the stepping motor to be measured corresponding to the repetition frequency; and a display means for displaying the characteristic of the detection output versus the repetition frequency of the drive pulse. have.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a stepping motor to be measured, 2 is a control unit such as a CPU,
Reference numeral 3 indicates a drive unit that drives the stepping motor 1 with a drive pulse having a repetition frequency corresponding to the frequency command Cf from the control unit 2. Reference numeral 4 indicates a drive unit that drives the stepping motor 1 with a drive pulse having a repetition frequency corresponding to the frequency command Cf from the control unit 2; This is a DC power supply that supplies direct current to the drive unit 3. 5 is a display unit such as a CRT, and 6 is a recording unit such as a floppy disk.

In such a configuration, when the repetition frequency of the drive pulses applied to the stepping motor 1 to be measured is gradually increased, the direct current (A) flowing through the resistor 4a decreases due to the influence of the inductance of the motor windings. . However, when a certain point (f2) is reached, the motor goes out of step and cannot rotate in response to this repetition frequency, and the inductance of the motor windings rapidly decreases, and the DC current (A) rapidly increases. do. Furthermore, when the repetition frequency of the drive pulse is gradually lowered, at a certain point (f1), the motor resumes normal rotation in response to the repetition frequency of the drive pulse at that time, and the current characteristic exhibits the hysteresis characteristic as shown in Figure 2. It will be shown. At this time, f1 is the maximum self-starting frequency, and f2 is the maximum response frequency.
This shows actual measurement results and shows that the desired characteristics can be easily obtained.

[0008]

As explained in detail above, according to the present invention, the characteristics of the maximum self-starting frequency and the maximum response frequency, which are the most important operating characteristics of a stepping motor, can be instantly detected without the need for a rotation detection sensor. Since it can be easily measured with high accuracy, it is particularly applicable to stepping motor manufacturing lines, and can have a great effect on quality control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram for explaining the operation of the embodiment in FIG. 1;

FIG. 3 is an actually measured characteristic diagram according to the embodiment of FIG. 1;

[Explanation of symbols]

1 Stepping motor to be measured 2 Control section 3 Drive part 4 DC power supply 5 Display section 6 Recording Department

Claims (1)

[Claims] 1. A driving means for changing the repetition frequency of a drive pulse of a stepping motor to be measured, and an average value or an effective value of a driving current of the stepping motor to be measured corresponding to the repetition frequency of the driving pulse as a detection output. A frequency characteristic measuring device for a stepping motor, comprising: a control means; and a display means for displaying a characteristic of the detection output versus the repetition frequency of the drive pulse.