Reviewing a washing machine isn't quite as simple as running some dirty laundry through a cycle -- here's the how and why of our test methodology. Production crews make laundry seem so magical in commercials. In these ads, disgruntled parents lament over the stubborn grass and grape juice stains that their current washing machine just can't handle and suddenly, voila! While I've fallen victim to the hypnotic allure of commercials like these on more than one occasion , they don't exactly reflect reality. Our job is to determine how well each washer actually cleans.
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List of electrical and electronic measuring equipmentVIDEO ON THE TOPIC: Measuring Devices for a Machinist
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Please check your Internet connection and reload this page. If the problem continues, please let us know and we'll try to help. An unexpected error occurred. Add to Favorites Embed Share Translate text to:. Electric machines and power electronics experiments involve electrical currents, voltages, power, and energy quantities that should be handled with extreme diligence and care. All experiments must be performed in the presence of personnel trained to handle electricity at these voltage and current levels.
In case of emergency, evacuate the lab through any of the exits and dial Electrical Engineering. Electrical Safety Precautions and Basic Equipment. The "Safety Precautions" procedural section covers the major guidelines and precautions intended to achieve a safe lab and operating environment for people performing experiments. These guidelines are by no means inclusive of all necessary precautions, and local electrical safety rules and regulations should be followed.
Experiments involving electric machines and power electronics typically use common equipment to supply power and to measure electrical quantities. However, circuits and apparatus being tested vary for different experiments. The "Basic Equipment" procedural section provides an overview of major equipment used for most electric machines and power electronics experiments.
Specific equipment, circuits, and apparatus are introduced in each experiment as needed. Figure 1: Close-up of function generator screen and control panel. Please click here to view a larger version of this figure. Figure 2: DC power supply unit. Figure 3: Oscilloscope unit. Close up shows screen and control panel. Figure 4: A conventional grounded probe. Figure 5: Differential voltage probe. Figure 6: Side view of current probe.
Figure 7: Multimeter. Figure 8: Three-phase outlet. The electricity that powers machines, tools, and other experimental apparatus must be handled with care and attention. Bodily contact with high voltage and current can cause muscular spasms, burns, cardiac arrest, and even death.
Even small amounts of current passed through the body can cause electrocution. Laboratory experiments typically use equipment that complies with International Safety Standards. The Underwriters Laboratory UL label, for example, certifies that equipment meets these standards, which prevents certain types of hazardous exposure. However, electrical inputs and outputs, or customized equipment still pose a hazard.
This video will present electrical safety precautions and introduce common electrical equipment used in many types of laboratory experiments. When using electrical equipment, wear long pants, closed-toe shoes, and appropriate personal protective equipment. Avoid loose clothing, and remove any dangling or metal accessories that can accidentally contact electricity.
Outlets for three-phase AC power can provide up to volts and over 10 amps. So power sources must be handled with respect. A clean lab environment is important for mitigating hazards. Avoid loose or frayed wires, cables, and connections. Know how to turn off all equipment, power supplies, and circuit breakers. Make sure that at least two people work on an experiment that has accessible DC power greater than 50 volts.
Use the same precautions with single-phase or three-phase AC mains power. Assume any exposed metal carries live electricity unless verified. Before changing a setup, turn off or unplug power sources used in the experiment. Proper grounding of equipment ensures the chassis is at earth-ground potential, which prevents electrical shock.
Always plug equipment into AC outlets with the power cord intended for it. Equipment that is hotter than expected is both a hazard and a symptom of a problem that should be addressed. Finally, turn off all equipment after an experiment is finished, and turn off unused equipment before leaving the lab. Now that basic safety precautions have been presented, the operation of some common electrical equipment will be demonstrated in the laboratory.
A function generator produces signals for other equipment needing an excitation or a drive voltage. The most common periodic outputs are sinusoidal, triangular, sawtooth, and square waves, which may be adjusted in amplitude, frequency, and DC offset. The output of the function generator is connected to the circuit or equipment using cables. Typically a BNC connector is used at one end, and alligator clips at the other end for easy connection to a circuit. A DC power supply provides voltage or a current to operate other electrical equipment.
The adjustable output of a typical low-voltage laboratory supply ranges between 0 and 36 volts. Most single-output DC power supplies have three terminals: plus, minus, and ground. The plus terminal is connected to the higher voltage input of downstream equipment. The minus terminal is connected to the lower voltage input. The output is the voltage or current between the plus and minus terminals, which are electrically isolated from the ground. The ground terminal is a fixed earth-ground reference that is zero volts.
Other common power sources include single-phase AC power from a standard wall outlet, or three-phase AC power. Single-phase power has one hot line and one neutral line for carrying current and delivers volts.
Three-phase power delivers higher voltages via three hot lines, with AC voltage on each line equal in frequency and magnitude, and degrees out of phase from one another. The result can supply , , and volts, with correspondingly greater power. Handling three-phase power requires special training and safety precautions. Next, a variable autotransformer, also known as a Variac, is used to either step up or down AC voltage. This is useful in applications requiring non-standard voltages or where the voltage must be varied.
Note that the Variac does not provide electrical isolation, so avoid touching the output at any setting. An oscilloscope displays the voltages of time-varying signals, and is used to study the behavior of circuits. Oscilloscopes may have multiple channels, each displaying a single waveform. The two main types of probes used with this instrument are the conventional grounded probe and the differential probe. Here a regular grounded probe is connected to channel one. The grounded probe is usually rated to tolerate several hundred volts and measures voltage between the probe tip and its ground lead.
The ground lead is tied to earth ground at the chassis of the oscilloscope. It is important to connect the ground lead only to a point in the circuit that is also grounded.
Touching a ground lead to any other point will cause a short-circuit to ground. Now connect channel one of the oscilloscope to the output of the function generator, then turn it on. Adjust the time-scale of the oscilloscope with the seconds per division knob, and adjust the voltage scale with the volts per division knob. The trigger level is the voltage that a signal crosses to cause synchronization of the oscilloscope.
Proper triggering minimizes noise in the display. Finally, the multimeter is a versatile handheld, or bench-top instrument, for measuring voltage, current, resistance, and other electrical quantities.
To measure voltage, insert the red probe into the contact labeled V Ohms and the black probe in the contact labeled COM for common. Turn on the DC power supply and set it to output 20 volts. Measure across the two output terminals by touching the red probe to the plus terminal and the black probe to the minus terminal. The multimeter reads 20 volts. Many experiments require the measurement of electrical quantities, and use basic instruments to provide this data.
The study of polar dielectric liquid bridges requires a high-intensity electric field between two beakers of fluid. The beakers are initially in contact, and then are slowly pulled apart to form the bridge. In this application, a high-voltage DC power supply generates 1, volts, which requires great care for safe handling.
To develop ways to control neural stem cell migration for therapeutic treatments, researchers studied their movement under the influence of an electric field. An experimental chamber used a DC power supply to generate the required controlled electric field. An ammeter measured the current and a multimeter measured the voltage across the test chamber, which was used to calculate electric field strength.
You've just watched JoVE's introduction to electrical safety and basic electronic equipment. You should now understand how to work safely with electricity and how to use some basic electrical test equipment.
Thanks for watching! Safety is the most important practice in an electrical engineering laboratory.
A student in Professor Martin Culpepper's Course 2. Internal Combustion Engines. Design and Manufacturing I. Finite Element Procedures for Solids and Structures. Nano-to-Macro Transport Processes.
Production and Manufacturing Equipment
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Manufacturing Site ISO Certifications
Enter search terms. Print This Page. Subpart A - Materials for Construction and Repair. Subsection F - Cleaning of Equipment and Utensils. Subpart G - Sanitization of Equipment and Utensils. Subpart E - Refuse, Recyclables, and Returnables. Subpart B - Design, Construction and Installation.
Calibration is a comparison between a known measurement the standard and the measurement using your instrument. Typically, the accuracy of the standard should be ten times the accuracy of the measuring device being tested. However, accuracy ratio of is acceptable by most standards organizations. Calibration of your measuring instruments has two objectives. It checks the accuracy of the instrument and it determines the traceability of the measurement. In practice, calibration also includes repair of the device if it is out of calibration. A report is provided by the calibration expert, which shows the error in measurements with the measuring device before and after the calibration. To explain how calibration is performed we can use an external micrometer as an example. Here, accuracy of the scale is the main parameter for calibration. In addition, these instruments are also calibrated for zero error in the fully closed position and flatness and parallelism of the measuring surfaces.
Electrical Safety Precautions and Basic Equipment
From Wikipedia, the free encyclopedia. Below is the list of measuring instruments used in electrical and electronic work. Name Purpose Ammeter Ampermeter Measures current Capacitance meter Measures the capacitance of a component Curve tracer Applies swept signals to a device and allows display of the response Cos Phi Meter Measures the power factor Distortionmeter Measures the distortion added to a circuit Electricity meter Measures the amount of energy dissipated ESR meter Measures the equivalent series resistance of capacitors Frequency counter Measures the frequency of the current Leakage tester Measures leakage across the plates of a capacitor LCR meter Measures the inductance, capacitance and resistance of a component Microwave power meter Measures power at microwave frequencies Multimeter General purpose instrument measures voltage, current and resistance and sometimes other quantities as well Network analyzer Measures network parameters Ohmmeter Measures the resistance of a component Oscilloscope Displays waveform of a signal, allows measurement of frequency, timing, peak excursion, offset, Psophometer Measures AF signal level and noise Q meter Measures Q factor of the RF circuits Tachometer Measures speed of motors Signal analyzer Measures both the amplitude and the modulation of a RF signal Signal generator Generates signals for testing purposes Spectrum analyser Displays frequency spectrum Sweep generator Creates constant-amplitude variable frequency sine waves to test frequency response Transistor tester Tests transistors Tube tester Tests vacuum tubes triode, tetrode etc.
The basic layout of the three main types of milking machines are the same. Each has a pump to remove air from the vacuum pipeline, a vacuum regulator and a container to collect the milk that comes into the teatcup assembly during milking. The principle of machine milking is to extract milk from the cow by vacuum. The machines are designed to apply a constant vacuum to the end of the teat to suck the milk out and convey it to a suitable container, and to give a periodic squeeze applied externally to the whole of the teat to maintain blood circulation. A milking machine installation consists of a pipework system linking various vessels and other components which together provide the flow paths for air and milk. The forces necessary to move air and milk through the system arise from the fact that it is maintained at a vacuum. Thus it is atmospheric pressure which forces air, and intra-mammary milk pressure which forces milk, into the system and the combination of these forces causes flow. To be a continuous operation it is necessary to remove air and milk from the system at appropriate rates. Although milking machines have now developed into systems that show considerable diversity they have the same basic components. The air is removed by a vacuum pump at a constant rate. In a bucket or direct-to-can machine milk is removed from the system by disconnecting the milk container; in milking pipeline and recorder machines the milk is removed by a milk pump or releaser.
NCBI Bookshelf. Working safely with hazardous chemicals requires proper use of laboratory equipment. Maintenance and regular inspection of laboratory equipment are essential parts of this activity. Many of the accidents that occur in the laboratory can be attributed to improper use or maintenance of laboratory equipment. This chapter discusses prudent practices for handling equipment used frequently in laboratories. The most common equipment-related hazards in laboratories come from devices powered by electricity devices for work with compressed gases, and devices for high or low pressures and temperatures. Other physical hazards include electromagnetic radiation from lasers and radio-frequency generating devices.
Why Calibration of Your Measuring Instruments is Important
Copper is a mineral and an element essential to our everyday lives. It is a major industrial metal because of its high ductility, malleability, thermal and electrical conductivity and resistance to corrosion. It is an essential nutrient in our daily diet. And, its antimicrobial property is becoming increasingly important to the prevention of infection. It ranks third after iron and aluminum in terms of quantities consumed in the USA. The U.
How we test: Washing machines
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical e. The study of wear and related processes is referred to as tribology.
Production and manufacturing equipment was where it all began for Klotz and continues to be a field we are highly proficient in, for example with the fully-automated Klotz ornamental and facing ring production system which is legendary around the world in the house wares industry. Even before the measurement and testing technology and then later on the assembly technology became important pillars of the company, we were developing and building many solutions in the production and fabrication technology field.
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Глубокая сердечная боль, сопровождавшая все воспоминания о погибшей дочери, полностью овладела Николь. Слезы текли по ее щекам, рыдания сотрясали - О Кэти. - стонала Николь, укрывая лицо руками.