SU1467220A1 - Device for sensing turbomachine shaft stoppage - Google Patents

Abstract

The invention relates to energy and m. used to control the rotation of units in power plants. The circuit of the invention is to simplify the design of the device. A rotational speed sensor 1 is connected to parallel-installed analog-to-digital converters (p) 3 and 4 and a driver 8, the inputs of which are combined. Outputs P are connected to an adder 5, the output of which is connected to a series-installed comparator 6, having a setup input, a counter 7 and an alarm unit 2. The output of the driver is connected to a serially connected multiplier 9 frequency and the distributor 10 pulses, the outputs of which are connected to the clock inputs P 3, 4, the adder and the counting input of the counter. Operation -P 3, 4 and adder 5 is clocked by pulses coming from the distributor, which are formed along the leading edges of the multiplied frequency pulses, the pulses alternating in time. The multiplication factor of the multiplier is selected depending on the required number of measurements during one revolution of the rotating shaft, and the number of samples is determined by the sensitivity of the sensor. 2 Il. S (L 4 0 tc

Description

I1467220

The invention relates to energy and can be used to control the rotation of aggregates in a power plant.

The purpose of the invention is to simplify the design.

Fig. 1 shows a functional: device diagram; on fig. 2 - time-: on the signal diagram. . Q The device (Fig. 1) contains a sensor 1 of the frequency of the joint with a transform; signal body, signaling unit 2, as well as analog-to-digital converters (ADC) 3 and 4, adder 5 digital- 15 comparator b, counter 7, connected in series shaper, tel 8, frequency multiplier 9 and distributor 10 pulses, which in aggregate, they represent the block I1 20 of the control of the end of braking. At the same time, the AC 3 and 4 are connected by informational-: input inputs, which are connected; also, with the converter output, are dated by the back edges of the VMH pulses. The pulse sequence at the input of the frequency multiplier 9 comes from the output of the imaging unit 8, which forms the pulses F fu (figure 2, diagram d) at the moment of zero crossing from low to high analog signal (FIG „2, diagram a)

The multiplication factor K of frequency multiplier 9 is selected depending on the required number of measurements (samples) during one revolution of the rotating shaft, and the number of samples is determined by the sensitivity of the sensor 1 o

At the moment of time to (fig2), at the information inputs of ADC 3 and 4 there is an analog level signal AO c, With the arrival of a clock pulse TI 1, ADC 3 converts the analog signal AO (first sample) into a code

MO. At the moment t with the arrival of the tick 1 rotation frequency and the input of the form 25 T 2 ADC 4 converts the analog signal A (second sample) to the NA code ,. The third sample is taken at time 11 with the arrival of the next TI 1 pulse, according to which A1GT 3 converts the analog signal A into a KA code. etc. Using the clock pulse of TI 3, the adder 5 calculates the difference code N - I NA - MO I without taking into account the sign that enters the digital comparator 6. The latter compares the DI code with the setting Ng, the value of which is determined based on the sensitivity of the converter and the presence of interference in the channel .

worldizer 8 The information inputs of the adder 5 are connected respectively to the outputs ASCH1 3 and 4, and the output is connected to. the input of the digital comparator 6 o The installation input of the counter 7 30 is connected to the output of the digital comparator 6 and the input of the signaling unit 2. The outputs of the distributor 10 pulses are connected, respectively, to the clock inputs SCHP 3 and 4, with the tact jg

the running input of the adder 5 and the counting input of the counter 7,

The device works as follows.

Analog Signal (FIGO25 Diagram-40

ma a) from the output of the pulse converter of the sensor I, the rotational frequency is fed to the combined information inputs of the first 3 and second 4 ADCs. The operation of the ADC 3 and 4 and the adder d 5 is clocked by pulses TI 1, TI 2, and TI, 3, arriving from the distributor I O of the pulses (figure 2, diagrams g, d, e) o To the input of the distributor 10

pulse frequency f MHI comes from a multiplier 9 frequency (figure 2, chart d).

The clock and fflyls TI 1 and TI 2 are formed on the leading edges of the multiplied frequency pulses, So they alternate. For example, if TI 1. pulses are formed from odd fumke pulses. then the impulses TI 2 even on O Shshulsy TY 3 form

The fronts of VMH pulse pulses are fed to the input of the frequency multiplier 9 from the output of the imaging unit 8, which is formed by the pulses of F fu (figure 2, diagram d) at the moment of zero crossing from a low level to a high analog signal (Fig. a diagram a)

The multiplication factor K of frequency multiplier 9 is selected depending on the required number of measurements (samples) during one revolution of the rotating shaft, and the number of samples is determined by the sensitivity of the sensor 1 o

At the moment of time to (fig2), at the information inputs of ADC 3 and 4 there is an analog level signal AO c, With the arrival of a clock pulse TI 1, ADC 3 converts the analog signal AO (first sample) into a code

MO. At time t with the arrival of 5 T 2 ADC 4 converts analog sig0

g

0

0

five

cash A (second sample) in the code NA ,. The third sample is taken at time 11 with the arrival of the next TI 1 pulse, according to which A1GT 3 converts the analog signal A into a KA code. etc. Using the clock pulse of TI 3, the adder 5 calculates the difference code N - I NA - MO I without taking into account the sign that enters the digital comparator 6. The latter compares the DI code with the setting Ng, the value of which is determined based on the sensitivity of the converter and the presence of interference in the channel .

When the shaft rotates, the 4NN condition is always met. In this case, the output signal of the comparator 6 zeroes the counter 7 and keeps it in this state.

The samples at times t and t j correspond to the shaft stop (Fig. 2) “In this case, JN, +, - M / O and condition 4K NB is satisfied. At the same time, the output signal of the digital comparator 6 allows the counter 7 to count TI 3 pulses. When the counter 7 of the number of TI 3 pulses arrives at the counting input, which is equal to its scaling factor, an overflow signal appears that goes to the input of the signaling unit. Overflow of the counter 7 confirms the accuracy of the information about the shaft stop. If the flN N0 condition is fulfilled for a short time, for example, due to the presence of smooth extremes on the quasi-sinusoidal signal of sensor 1, which initiates the operation of comparator 6, then counter 7 will not have time to overflow. , zeroed counter 7,

As a frequency multiplier 9, any of the known multipliers can be used, the principle of which

Tick of shaft rotation frequency with signal converter, formative actuator, digital comparator, counter with counting and installation inputs and signaling unit, characterized by the fact that, with a simplified circuit, two analog-to-digital converters are added to it 0 watches with information and clock inputs each, an adder with information and clock inputs, and subsequently switched on frequency multiplier and distributor, to synthesize the output frequency from the frequency of the reference generator - 5 pulses, m output transducers controlled by ra l pulse divider is connected to the input forchastoty coefficient whose value is determined by dividing dpi- telnosti code period multiplied frequency.

A / D converters 3 and 4 and digital adder 5 20 are made with buffer memory at the outputs, overwriting into which is clocked by pulses TI 1, TI 2, TI 3.

As sensor 1, a contactless eddy current transducer is used; 25 are connected to the clock inputs of a movement in electric-to-digital converters and

connected to its output from the frequency multiplier input, and to the information inputs of analog-to-digital converters, whose outputs are connected to the information inputs of the adder, connected to the digital comparator output, to the outputs of the pulse distributor

20

Tick of the shaft rotation frequency with a signal converter, a shaper, a digital comparator, a counter with counting and installation inputs, and an alarm unit, differing from the fact that, with a simplified circuit, two analog-digital converters are added to it each with information and clock inputs, an adder with information and clock inputs and sequentially switched on frequency multiplier and pulse distributor, the output of the pulse converter connected to the input is connected to the beat ruyuschim input analog-to-digital converters and

connected to its output from the frequency multiplier input, and to the information inputs of analog-to-digital converters, whose outputs are connected to the information inputs of the adder, connected to the digital comparator output, to the outputs of the pulse distributor

signal.

Claims (1)

The invention device for fixing the stop of the shaft of the turbine set, containing the date the adder and the counting input of the counter, the installation input of which is connected to the output of the digital comparator, and the output - to the alarm unit, d.