SU1075166A2 - Asynchronous dc tachogenerator - Google Patents

Abstract

Asynchronous DC Tachogenerator on auth.St. 972406, characterized in that, in order to extend the measurement range, it is additionally equipped with two frequency multipliers, two two-way limiting amplifiers, a full-wave rectifier, a stopper filter, a peak transformer and a digital meter with a measuring instrument, while the output windings of the first and the second stages of asynchronous machines through sequentially connected, respectively, the first frequency multiplier, two-way amplifier-limiter and the second frequency multiplier, two-way amplifier-limiter Connected to series-connected two-half-wave rectifier, filter plug, peak-transformer and digital measuring instrument. w 01 about Oi

Description

The invention relates to instrumentation and can be used in systems to obtain analog and discrete signals proportional to the speed of rotation.

An asynchronous DC tachogenerator 5 is known, which contains two cascade electric machines whose rotors are rigidly connected to each other, the rotor windings of each cascade of asynchronous machines are connected 10 in an inverse circuit, and three-phase field windings are connected to a power source with direct and reverse phase rotation , and two three-phase rectifiers, connected by inputs to a ^ 5 subtraction circuit with a resistor. The magnitude of the EMF in the output windings of the tachogenerator is proportional to the rotor speed. The emf frequency of the output windings also varies depending on the shaft rotation speed [1J.

The disadvantage of such a tachogenerator is the limited measurement range in the low-speed region due to the fact that the discrete information obtained in the output windings of each of the machines in the form of the EMF frequency cannot be directly used, since this information does not display the actual value of the rotation speed shaft. - ⁵⁰

The aim of the invention is to expand the measuring range.

This goal is achieved by the fact that the asynchronous tachogenerator of a direct current is additionally equipped with two frequency multipliers, two two-sided amplifier-limiters, a half-wave rectifier, a filter plug, a transformer and a digital measuring device, while the output windings of the first and second cascades of asynchronous machines through series-connected respectively the first frequency multiplier, two-way 45th amplifier-limiter and second frequency multiplier, two-way amplifier-ogre ichitel connected to a full-wave rectifier connected in series, filtruprobke peak-digital transformer and the measuring device.

The drawing shows the proposed device.

The device contains an asynchronous tachogenerator 1 direct current 5E consisting of two cascade asynchronous electric machines 2 and 3, two three-phase rectifiers 4 and 5 and a subtraction circuit with a resistor 6, as well as two frequency multipliers 7 and 8, 60 two two-sided amplifier-limiter 9 and 10, half-wave

VNIIPI Order 491/38 rectifier 11, filter plug 12, peak transformer 13 and digital measuring device 14. In this case, the field windings of two cascade asynchronous machines 2 and 3 are connected to the network with the opposite phase rotation, and the output winding of each of the machines is connected simultaneously with a three-phase rectifier and with a frequency multiplier.

The device operates as follows.

An analog signal in the form of an EMF that varies in proportion to the rotor speed is obtained from the three-phase output windings of two cascade asynchronous machines 2 and 3 and is converted using two three-phase rectifiers 4 and 5 and a subtraction circuit with a resistor 6.

Information for the formation of a discrete signal is the EMF frequency of three-phase windings of both cascade machines, which also vary depending on the speed of rotation. This information is fed to the inputs of frequency multipliers 7 and 8 (transformer or semiconductor). The voltage of the multiplied frequency is equalized and amplified in amplitude with the help of two-sided amplifier-limiters 9 and 10. At the input of the rectifier 11, two voltages of the same amplitudes and close but not equal frequencies% are added and as a result there are beats that are described by the mathematical equation

U (t) = 2U _m costJ _e t'sin ω _ο t (1)

The frequency of the envelope of the beat oo _d is equal to half the difference collapsible frequency ω, -ω ₂ "2- o- ~ 'W and is proportional in this case, the rotor speed. From the resulting signal, rectified according to a half-wave circuit, a pulsating envelope is isolated using a filter plug 12 for the carrier frequency and its peak transformer 13 is converted into a sequence of pulses recorded by a digital measuring device 14,

At low rotational speeds, the beat quality is the best, since the EMF frequencies of the output windings are as close as possible in magnitude. Thus, the improvement of the output discrete signal will improve the accuracy of measurements at low speeds, and therefore expand the range of measurements in this area.

Circulation 823 Subscription

Branch of the PPP Patent, Uzhgorod, Project 4,

Claims (1)

ASYNCHRONOUS DC TACHOGENERATOR for ed. No. 972406, characterized in that, in order to expand the measuring range, it is additionally equipped with two frequency multipliers, two two-sided amplifier-limiters, a half-wave rectifier, a filter plug, a peak transformer and a digital measuring device, while the output windings of the first and the second cascade of asynchronous machines through the first frequency multiplier, two-way limiter amplifier and second frequency multiplier, two-way limiter amplifier connected in series -dvuhpoluperiodnomu to series connected rectifier, filter-tube, the peak-digital transformer and the measuring device § mu. , ''