SU991306A1 - Shaft rotation speed measuring device - Google Patents

Description

The invention relates to a digital 'electrical measuring technique and can be used to measure fluctuations in shaft rotation speed, for example, to determine slippage in belt drives of drive mud pumps.

A device for measuring. Fluctuations in the speed of rotation of the shaft, containing a speed sensor, a trigger phase meter, a master oscillator, keys, summing and subtracting counters [1].

However, this device contains a large number of logical and trigger elements and is characterized by the complexity of the operation algorithm, which reduces its reliability.

A device for measuring the shaft rotation speed is also known, which comprises a rotation angle sensor with a selsyn, a three-phase rectangular voltage generator, the first output of which is connected to the input of the three-beam selsyn winding and the first input of the phase converter is a code, the second input of which is connected to the selsyn output, and the output to the counting input of the subtracting counter, the outputs of which _ are connected to the inputs of the recording θ block, a synchronizer, the first output of which is connected to the third input of the phase – code converter, and the second to the input of the counter information census [2].

However, this device does not allow to measure fluctuations in the speed of rotation of the shaft.

The aim of the invention is the ability to measure fluctuations in the speed of rotation of the shaft.

This goal is achieved by the fact that four logical elements AND, two logical elements OR and a block of speed settings are introduced into the device, the second output of the three-phase rectangular voltage generator connected to the first input of the first and third logical elements And, the third output connected to the first input of the second and fourth logical elements AND, the second inputs of the first and fourth elements AND are connected to the third output of the synchronizer, the fourth output of which is connected to the second inputs of the second and third logical elements And the outputs of the first and second logical elements AND are connected to the inputs of the first logical element OR, the outputs of the third, its fourth logic elements AND are connected to the inputs of the second logical element OR, and the outputs of the OR elements are connected respectively to the second and third input of the three-beam selsyn winding , while J. the output of the speed settings block is connected to the input of the counter information census.

The drawing shows a diagram of the device. jq

The device contains a rotation angle sensor with selsyn 1, a three-phase rectangular voltage generator 2, one of the outputs of which is connected to the input of a three-beam winding sel—, 'sina 1, a phase 3 converter - code,' · * the first input of which is connected to the output of generator 2, the second the input is connected to the output coil of selsyn 1, and the output to the counting input of the subtracting counter 4 with an arbitrary module 20, the output of which is connected to the recording unit 5.

The apparatus also comprises a synchroniser 6, a first output coupled to an input 25 of Tell transformation start 3 and the second - to the input of the counter 7, census information, wherein vtorsy output generator 2 is connected to first inputs of the AND gates 8 _and 8 and _3, the third output of the generator 2 is connected to the first inputs of the logical elements AND 8 ₂ and 8 ₄ . The second inputs of the elements 8 ₄ and 8 _{4 are} connected to the third output of the synchronizer 6, the outputs of the elements 8 ₄ and 8 _{2 are} connected to the inputs of the 35 logical element OR 9 ₄ , the outputs of the elements 83 and 8 _{4 are} connected to the inputs of the logical element 9 ₂ , and the outputs elements 9 ^ And 9 _{2 are} connected respectively to the first and second to the branches of the three-beam winding selsyn 1. In addition, the device contains a source 10 of the code, the output of which is connected to the input 7 of the valve.

The device operates as follows.

The signals of the generator 2 of a three-phase rectangular voltage after passing through the logic elements Y 8 and OR 9 excite a discontinuous rotating magnetic field in the sync 1, which induces a sinusoidal signal in the single-beam coil of the sync 1. The rotation angle of the selsyn rotor 1 is proportional to the phase difference in the single-beam winding and one of the 55 three-beam phases, the resulting phase shift is converted into a unitary code by the converter 3. The rotation angle sensor 1 is turned on so that when the rotation angle of the shaft 60 is increased, the phase shift code increases.

Before the start of the next measurement step, according to the signal of synchronizer 6, the valve and the code (x ₀ ) of the block are opened, 10 is entered in the subtracting counter - 65 clock 4. The signal from the third output of synchronizer 6 allows the signals of generator 2 to pass through the logic elements 8 ₄ and 8 ₄ . At the same time, the magnetic field of selsyn 1 rotates. According to the signal from the first output of the synchronizer 6, the converter 3 is turned on. The input of the counter 4 receives the unitary code to supplement the current angle of rotation of the rotor selsyn 1 ((-χ ^), where N is the number of pulses corresponding to the complete rotation of the rotor selsyn 1 and the module of the subtracting counter 4, and χ _η is the number of pulses equal to the current angle of rotation of the selsyn rotor. The signal of the logical unit from the fourth output of the synchronizer 6 allows the passage of the signals of the generator 2 through the logical elements 8 ₂ and 8 ,. In this case, the magnetic field of selsyn 1 rotates in the forward direction. The signal from the first output-synchronizer b turns on the converter 3. At the same time, a unitary code of the current angle of rotation of the rotor selsyn 1 (x ₂ ) is received at the input of the counter 4. The value of x ₀ is chosen equal to the maximum speed of rotation of the shaft, in relation to which the fluctuation of the rotation speed is determined.

As a result, a code is generated in counter 4 that is equal to the absolute difference between the maximum shaft rotation speed and the actual shaft rotation speed according to the expression:

S = ((x ₀ - (Ν - χρ) mod Nx ₂ ) modN.

Performing a modular operation in the counter 4 provides a result in the direct code regardless of the transition of the rotor selsyn 1 through the zero state. For instance:

1) N = 1000; x ₀ = 400; x ₄ = 100; x ₂ = 450; S = ((400 - (1000-100)) mod 1000 - 450) mod 1000 = 50;

2) N = 1000; X _o = 400; X ^ = 900; x ₂ = 250; S = ((400 - (1000 - 900)) mod 1000 - 250) mod 1000 = 50.

This embodiment of the device allows you to measure fluctuations in rotational speed with fairly high accuracy.

Claims (2)

1. Authors certificate of the USSR 690389, cl. G 01 P 3/48, 1979. 2. USSR author's certificate number 751972, cl. E 21 V 45/00, 1980 (prototype). Xgjn