Mechanical, electrical, and contactless tachometers are described for measuring rotational speed. Mechanical tachometers include revolution counters, hand speed indicators, tachoscopes, and centrifugal and vibrating reed types. Electrical tachometers comprise eddy current, DC and AC tachogenerators, and contactless types like magnetic and photoelectric pickups. Tachometers are also classified based on data acquisition (contact vs non-contact), data type (analog vs digital), and measurement technique (time vs frequency). Contact tachometers must physically attach to rotating objects while non-contact tachometers measure speed remotely.
This ppt includes measurement devices of speed measurement like various tachometers, acceleration measurement devices as well as vibration measurement devices, displacement sensing accelerometers, LVDT, piezoelectric tachometer, stroboscope.
This ppt includes measurement devices of speed measurement like various tachometers, acceleration measurement devices as well as vibration measurement devices, displacement sensing accelerometers, LVDT, piezoelectric tachometer, stroboscope.
This ppt contains the information regarding the measurement of force and various instruments that are used for the measurement of force. This a topic in the fifth unit of Metrology and instrumentation for the third mechanical in JNTUACEP.
for detailed information or video of this ppt just follow the youtube link attached below
https://youtu.be/aCMXmWc2poU
The transducer whose resistance varies because of the environmental effects such type of transducer is known as the resistive transducer. The change in resistance is measured by the ac or dc measuring devices. The resistive transducer is used for measuring the physical quantities like temperature, displacement, vibration etc.
The measurement of the physical quantity is quite difficult. The resistive transducer converts the physical quantities into variable resistance which is easily measured by the meters. The process of variation in resistance is widely used in the industrial applications.
The resistive transducer can work both as the primary as well as the secondary transducer. The primary transducer changes the physical quantities into a mechanical signal, and secondary transducer directly transforms it into an electrical signal.
Working Principle of Resistive Transducer
The resistive transducer element works on the principle that the resistance of the element is directly proportional to the length of the conductor and inversely proportional to the area of the conductor. equation-1
Where R – resistance in ohms.
A – cross-section area of the conductor in meter square.
L – Length of the conductor in meter square.
ρ – the resistivity of the conductor in materials in ohm meter.
The resistive transducer is designed by considering the variation of the length, area and resistivity of the metal.
Applications of Resistive Transducer
The following are the applications of the resistive transducer.
Potentiometer – The translation and rotatory potentiometer are the examples of the resistive transducers. The resistance of their conductor varies with the variation in their lengths which is used for the measurement of displacement.
Strain gauges – The resistance of their semiconductor material changes when the strain occurs on it. This property of metals is used for the measurement of the pressure, force-displacement etc.
Resistance Thermometer – The resistance of the metals changes because of changes in temperature. This property of conductor is used for measuring the temperature.
Thermistor – It works on the principle that the temperature coefficient of the thermistor material varies with the temperature. The thermistor has the negative temperature coefficient. The Negative temperature coefficient means the temperature is inversely proportional to resistance.
Measurement of speed:
Mechanical Tachometers
Electrical Tachometers
Stroboscope
Non contact type of Tachometers.
Stress & strain Measurements:
Various types- Electrical Strain Gauge.
Gauge factor
Method of usage of resistance strain gauge for bending compressive & Tensile strains
Usage for Measuring torque.
Strain gauge Rosettes.
This ppt contains the information regarding the measurement of force and various instruments that are used for the measurement of force. This a topic in the fifth unit of Metrology and instrumentation for the third mechanical in JNTUACEP.
for detailed information or video of this ppt just follow the youtube link attached below
https://youtu.be/aCMXmWc2poU
The transducer whose resistance varies because of the environmental effects such type of transducer is known as the resistive transducer. The change in resistance is measured by the ac or dc measuring devices. The resistive transducer is used for measuring the physical quantities like temperature, displacement, vibration etc.
The measurement of the physical quantity is quite difficult. The resistive transducer converts the physical quantities into variable resistance which is easily measured by the meters. The process of variation in resistance is widely used in the industrial applications.
The resistive transducer can work both as the primary as well as the secondary transducer. The primary transducer changes the physical quantities into a mechanical signal, and secondary transducer directly transforms it into an electrical signal.
Working Principle of Resistive Transducer
The resistive transducer element works on the principle that the resistance of the element is directly proportional to the length of the conductor and inversely proportional to the area of the conductor. equation-1
Where R – resistance in ohms.
A – cross-section area of the conductor in meter square.
L – Length of the conductor in meter square.
ρ – the resistivity of the conductor in materials in ohm meter.
The resistive transducer is designed by considering the variation of the length, area and resistivity of the metal.
Applications of Resistive Transducer
The following are the applications of the resistive transducer.
Potentiometer – The translation and rotatory potentiometer are the examples of the resistive transducers. The resistance of their conductor varies with the variation in their lengths which is used for the measurement of displacement.
Strain gauges – The resistance of their semiconductor material changes when the strain occurs on it. This property of metals is used for the measurement of the pressure, force-displacement etc.
Resistance Thermometer – The resistance of the metals changes because of changes in temperature. This property of conductor is used for measuring the temperature.
Thermistor – It works on the principle that the temperature coefficient of the thermistor material varies with the temperature. The thermistor has the negative temperature coefficient. The Negative temperature coefficient means the temperature is inversely proportional to resistance.
Measurement of speed:
Mechanical Tachometers
Electrical Tachometers
Stroboscope
Non contact type of Tachometers.
Stress & strain Measurements:
Various types- Electrical Strain Gauge.
Gauge factor
Method of usage of resistance strain gauge for bending compressive & Tensile strains
Usage for Measuring torque.
Strain gauge Rosettes.
Contactless tachometer using 8051 microcontroller2Siddharth Shahi
A small presentation on circuit diagram and working of a digital tachometer using 8051 mc.
Reference:http://www.electronicshub.org/contactless-digital-tachometer-using-8051-microcontroller/
1. Measuring the angle of a component.
2. Checking the sloping angle of a vee-block.
3. Measuring the angle of a cone or taper gauges.
4. Precise angular settings for machining operations.
Iron – Carbon Diagram is also known as Iron – Carbon Phase Diagram or Iron – Carbon Equilibrium diagram or Iron – Iron Carbide diagram or Fe-Fe3C diagram
The process of transformation of a substance from liquid to solid state in which the crystal lattice forms and crystals appear.
•Volume shrinkage or volume contraction
Please refer this file just as reference material. More concentration should on class room work and text book methodology.
Thermal aspects of Machining, Tool materials, Tool wear Cutting fluids and Machinability.
This chapter aims to provide basic backgrounds of different types of machining processes and highlights on an understanding of important parameters which affects machining of metals with their chip removals.
Metal cutting or Machining is the process of producing workpiece by removing unwanted material from a block of metal. in the form of chips. This process is most important since almost all the products get their final shape and size by metal removal. either directly or indirectly.
The major drawback of the process is loss of material in the form of chips. In this chapter. we shall have a fundamental understanding of the basic metal process.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
2. 2
Please refer this file just as
reference material. More
concentration should on class
room work and text book
methodology.
3. Tachometer, What’s That?
• Tachometer is used for measuring rotational speed
• Can be used to measure speed of a rotating shaft
• Can also be used to measure flow of liquid by attaching a
wheel with inclined vanes
3
Tachometers can be classified
1.On the basis of data acquisition
Contact
Non contact types
2. Classified as data type
Analog
Digital
3. On the basis of power .
Mechanical
Electrical
4. WhatAre the Different Types of
Tachometers?
• Classification of tachometers:
• Mechanical Tachometers
• Revolution counter
• Hand speed indicator
• Tachoscope
• Centrifugal tachometer
• Resonance (vibrating read) tachometer
• Electrical Tachometers
• Eddy current or drag cup tachometer
• Tachogenerator (DC and AC)
• Contactless electrical Tachometers
• Magnetic pickup tachometer
• Photo-electric tachometer
• Stroboscope
4
6. Revolution counter
• Revolution counter is used to measure an average of rational
speed instead of instantaneous rotational speed.
• It consists of a worm gear that is usually attached to a spindle.
It has two dials, an inner one and an outer one.
• The inner dials represent one revolution of the outer dials and
the outer dials represent on revolution of the spindle.
• The tachometer has a stopwatch attached to the revolution
counter and is used to indicated time.
• These are limited to low speed engines and measure
satisfactory upto 2000-3000r.p.m.
6
8. Hand speed indicator
• Hand Speed Indicator has an integral stopwatch and counter
with automatic disconnect.
• The spindle operates when brought in contact with shaft.
• Counter does not function until start and wind button is
pressrd to start watch and engage the clutch.
• The instrument indicates average speed over short interval in
r.p.m .
8
10. Tachoscope
• Tachoscope consists of revolution counter for timing device.
• The two components are integrally mounted and start
simultaneously when contact point is pressed against rotating
shaft.
• The rotational speed is computed from reading of counter
and timer.
• Tachometer can be used to measure speeds up to 5000r.p.m.
10
13. Centrifugal tachometer
• Centrifugal Tachometer operates on principle that centrifugal
force is proportional to speed of rotation.
• It consists two balls arranged about spindle. Centrifugal force
developed by these balls compress spring as function of speed
positions pointer.
• They are suitable for 4000r.p.m.
13
15. Resonance (vibrating read)
tachometer
• In Vibrating Read Tachometers a series of consecutively timed
steel rods are used to determine speed on basis of vibrations
created by machine.
• One end of rod is fixed to a base which is kept in contact with
any non-moving part of machine and other is attached to
calibrated scale.
• These can be used in speed range of 600-10000 rpm .
15
18. Eddy current or drag cup
tachometer
• An eddy-current tachometer uses the interaction of the
magnetic fields generated by a permanent magnet and a
rotor, whose speed of rotation is proportional to the eddy
currents generated.
• The currents tend to deflect a disk, which is mounted on the
shaft and restrained by a spring, through a certain angle.
• The deflection of the disk, which is rigidly connected to a
pointer, is indicated on a dial.
18
20. D.C. Tachogenerator
• In a D.C. generator the e.m.f generated depends upon the following
two factors:
(i) Field excitation
(ii) Speed
• If for the field system permanent magnet pole pieces are used, then
the generated voltage depends only on the speed. Hence the speed
can be computed by measuring the generated e.m.f.
• The shaft whose speed is to be measured is coupled to the
armature.
• A moving coil voltmeter is connected across the brushes to measure
the generated voltage. The variable resistance R is incorporated to
limit the current through the voltmeter.
• Since voltage is proportional to speed, the voltmeter may be
calibrated in terms of speed (r.p.m.).
20
22. A.C. Tachogenerator
• The inherent demerits associated with D.C. tachometer
generator, due to the provision of commuter and brushes, are
eliminated in A.C. tachometer generator.
• It consists of, like an alternator, a stationary armature (stator)
and a rotating field system (rotor). Owing to the generation of
e.m.f in a stationary coil on a stator, commutation problems
no longer exist.
• The alternating e.m.f. induced in the stationary coil is rectified,
and the output D.C. voltage is measured with the help of a
moving coil voltmeter (V).
• The ripple content of the rectified voltage is smoothened by
the capacitor filter (C).
22
23. A.C. Tachogenerator
23
As the speed depends on both the amplitude of the
voltage and frequency, anyone of them can be used as a
measure of the speed. In an A.C. tachometer, it is the
induced voltage that is considered as the required
parameter.
25. Magnetic pickup tachometer
• A coil wounded on permanent magnet not on iron core, this
configuration enable us to measure rotational speed of the
systems.
• In the construction of variable reluctance sensor, we use
ferromagnetic gearwheel. As the gearwheel rotates, change in
magnetic flux take place in the pickup coil which further
induces voltage. This change in magnitude is proportional to
the voltage induced in the sensor.
25
27. Pickup tachometer
• Various pick-up devices can be used in conjunction with a
digital counter to give a direct reading of speed.
• An inductive pick-up tachometer is shown in Figure (a).
• As the individual teeth pass the coil they induce an e.m.f.
pulse which is appropriately modified and then fed to a digital
counter.
• A capacitive pick-up tachometer is shown in Figure (b). As the
rotating vane passes between the plates a capacitance change
occurs in the form of a pulse.
• This is modified and then fed to the digital counter.
27
29. Photo-electric tachometer
• It consists of a opaque disc mounted on the shaft whose speed is to be
measured. The disc has a number of equivalent holes around the periphery. On
one side of the disc there is a source of light (L) while on the other side there is
a light sensor (may be a photosensitive device or photo-tube) in line with it
(light-source).
• On the rotation of the disc, holes and opaque portions of the disc come
alternatory in between the light source and the light sensor. When a hole
comes in between the two, light passes through the holes and falls on the light
sensor, with the result that an output pulse is generated. But when the opaque
portion of the disc comes in between, the light from the source is blocked and
hence there is no pulse output.
• Thus whenever a hole comes in line with the light source and sensor, a pulse is
generated. These pulses are counted/measured through an electronic counter.
29
30. Photo-electric tachometer
30
The number of pulses generated depends upon the foliowing factors:
i. The number of holes in the disc;
ii. The shaft speed.
Since the number of holes are fixed, therefore, the number of pulses generated
depends on thespeed of the shaft only. The electronic counter may therefore be
calibrated in terms of speed (r.p.m.)
32. Stroboscope
• The instrument operates on the principle that if a repeating
event is only viewed when at one particular point in it’s cycle
it appears to be stationary. A mark is made on rotating shaft,
and a flashing light is subjected on the shaft. The frequency of
the flashing is one very short flash per revolution.
• To determine the shaft speed we increases the frequency of
flashing gradually from small value until the rotating shaft
appears to be stationary, then note the frequency. The
frequency then doubled, if there is still one apparent
stationary image, the frequency is again doubled. This
continued until two images appear 180 degrees apart. When
first appear for these two images the flash frequency is twice
the speed of rotation. 32
33. Stroboscope
• Stroboscopes are used to measure angular speed between
600 to 20000 rpm .
• It’s advantage is that it doesn’t need to make contact with the
rotating shaft.
33
34. Comparison Between Analog and
Digital Tachometers
Analog Tachometer
• Has a needle and dial
type of interface
• No provision for
storage of readings
• Cannot compute
average, deviation,
etc
Digital Tachometer
• Has a LCD or LED
readout
• Memory is provided
for storage
• Can perform
statistical functions
like averaging, etc
34
35. Classification Based on Data
Acquisition Technique
• Contact type – The wheel of the tachometer needs to be
brought into contact with the rotating object
• Non Contact type – The measurement can be made without
having to attach the tachometer to the rotating object
35
36. Classification Based on
Measurement Technique
• Time Measurement – The tachometer calculates speed by
measuring the time interval between the incoming pulses
• Frequency Measurement – The tachometer calculates speed
by measuring the frequency of the incoming pulses
36
37. ComparisonBetweenContactandNonContact
Tachometers
Contact Type
• The tachometer has to be in
physical contact with the
rotating shaft
• Preferred where the
tachometer is generally fixed to
the machine
• Generally, optical encoder /
magnetic sensor is attached to
shaft of tachometer
Non Contact Type
• The tachometer does not need
to be in physical contact with
the rotating shaft
• Preferred where the
tachometer needs to be mobile
• Generally, laser is used or an
optical disk id attached to
rotating shaft and read by a IR
beam or laser
37
38. ComparisonBetweenTimeandFrequencyBased
Measurement
Time Based
• The tachometer calculates
speed by measuring the time
interval between pulses
• More accurate for low speed
measurement
• Time to take a reading is
dependant on the speed and
increases with decrease in
speed
• The resolution of the
tachometer is independent of
the speed of the measurement
Frequency based
• The tachometer calculates
speed by measuring the
frequency of pulses
• More accurate for high speed
measurement
• Time to take a reading is
independent of speed of
rotation
• The resolution of the
tachometer depends on the
speed of the rotating shaft
38
39. How To Choose a Tachometer?
• Accuracy
• Precision
• Range
• Acquisition Time
• Contact type / Non Contact type
• Portable / Fixed
• Digital / Analog
• Cost
39
40. Calibration
• Why calibrate?
• Wrong calibration = Wrong readings
• Calibration compensates for ageing, wear and tear and
other degrading effects
• How to calibrate?
• Calibration is done by comparing the reading from
tachometer to a standard speed
• Necessary changes are made so that the actual
reading matches the desired reading
40