SU535600A1 - Device for controlling the speed of the magnetic carrier - Google Patents

Description

Negative potential persists until the condenser of the one-shot 4 is recharged, after which an avalanche-like transfer of the first one-shot 4 to the initial steady state occurs. The charge time constant of this capacitor is much less than the constant discharge time one-shot 4 is significantly less than the pulse duration.

Thus, in the presence of a tachogenerator signal 1, at the output of the first one-oscillator 4, opposite-polarity pulses with an amplitude of ± UQ are formed, the negative pulse duration being constant, and the positive one depending on the frequency of the tachogenerator signal 1.

Diversified pulses from the output of the first one-oscillator 4 are fed to the input of the first low-pass filter 5, and an average voltage value is set at its output, the magnitude and sign of which depends on the frequency of the signal from tachogenerator 1, and hence the rotational speed of the electric motor 7

The operation of the second one-shot 8 and the second low-pass filter 9 is similar to the work of the first one-shot 4 and the first low-pass filter 5.

In the absence of a signal at the input of the first single vibrator 4 and the second single vibrator 8, the voltage at the outputs of the first low pass filter 5 and the second low pass filter 9 is t / o. When the frequency of tachogenerator 1 changes from zero to 2 / n, the voltage at the output of the first low-pass filter 5 changes linearly from / o to minus / o and is zero at the frequency fa (where / n is the tuning frequency of the first oscillator 4). At the output of the second low-pass filter 9, the voltage varies linearly from Ug to zero as the frequency of the input signal changes from zero to 2 / n - A /. When the frequency of the signal from tachogenerator 1 becomes greater than 2 / n-D | D, then a negative potential is established at the output of the second low-pass filter 9.

The value A / is chosen such that at the frequency 2 / n the voltage at the output of the second low-pass filter provides at the output of the first one-oscillator 4 and the first low-pass filter 5 the voltage is set to Uo for the time during which the frequencies of the tachogenerator 1 would be greater or equal to 2 / nTakim way, the output of the first low-pass filter error signal, the magnitude and sign of which depends on the speed of rotation

the motor 7 and, therefore, the frequency of the tachogenerator 1, is fed to the input of the amplifier-converter 6, the output of which is connected to the measles of the electric motor 7.

The amplified and transformed error signal acts on the voltage applied to the motor core, keeping its rotational speed constant.

Frequency divider 3 is a series connection of triggers with counting inputs and is designed to obtain a series of standard rotational speeds of electric motor 7. When switched on between the output of limiting amplifier 2 and the input of one-vibrator 4 K triggers, the shaft speed of electric motor 7 will increase by 2 times (where K 0 , 1, 2, 3, 4, 5). Along with a discrete switch of speeds, the device described allows their smooth adjustment by ± 30% relative to the nominal value by changing the resistor value of the one-shot 4, instead of which, in this case, include a potentiometer.

The technical and economic effect of using the invention is, according to preliminary data (in comparison with the use of several single-speed devices), of the order of 100 thousand rubles.

Claims (2)

1. Microelectric motors for automation systems. Sat by ed. E. A. Lodochnikova et al. M., “Energie, 1969, fig. 2-13. 2. The exchange of experience in radioindustry. Sat 1974, no. 8, s. 85-86.