What conditions must be done before a generator can be connected to a 3-phase system?
Assuming the generator is in good condition and designed to be connected to a power grid. A generator can be connected by ensuring the generator is at very nearly the same speed as the grid (typically very slightly faster) and is generating a similar voltage. When the phases of the generator and grid align, the circuit breakers can be closed and the generator will become locked to the grid. If the generator is connected to the grid without being in phase, the difference in phase will allow significant current to flow and in some situations can actually be worse than a direct short circuit. As a result of this power companies use sophisticated equipment to ensure that generators can be safely connected to the grid without damage.
Household, camping and most industrial generators are not designed to be synchronised with the grid and should not be connected to a grid system.
Why does an electric iron have a resistance of 15 ohms?
I never measured the resistance of an electric iron, but: the 15 ohm resistance is probably required to develop a required 806 watts of power. Using Ohm's law, I(current) = E(voltage)/R(resistance), therefore
I(current) =110 volts/15 ohms = 7.33 Amps (current), and, Power (watts) = E(voltage) X I(current); 110 volts X 7.33 amps = 806 watts. The iron requires that wattage to develop enough heat in the sole of the iron. Hope this helps.
What does the aggregate mean in aggregate planning?
In aggregate planning, you look at things from a far point of view. In other words, looking at the big picture of the whole plant. Not caring about the small details, such as a particular product , a particular worker or where this worker is assigned.
You can take the an average for products, if the company produces many products, as a weighted average of how much you produce of each type. So, now you have a single average product to plan for. The similar thing for the number of workers. we just need the amount of items they can produce per operation day. we do not look into the detail of which department this worker is going to work in.
In general, aggregation is used to simplify the problem and then get best solution to use when disaggregating the components in the following steps of the production planning.
Is there a mathematical formula for figuring out the proper amount of weight for diving?
There's all sorts of mathematical equations, but they will give you an approximate only. There are too many variables to give an accurate formula. You can not look only at body weight, but need to take into account Muscle, fat, and bone density. Also wetsuit age/condition and diver's experience levels make a big difference. Best way is to try and see. Proper weighting for a person is proved when they can perform a safety stop (15ft / 5m) with no air in their jacket, and an empty (500psi) tank. I have found that any formula generally overweights people. As a general rule, most divers use about 10% of their body weight. Depending on the thickness of your wetsuit. Myself, wearing a 7/5mm suit, I use 17lbs. of weight. My body weight is 163. So... I recommend 10% of your body weight. (ps. I am also a Scuba Instructor) I too am a Dive Instructor, and feel most divers are overweighted. I've never found a formula that works, and say try it and see. I weigh 190lb, and with a full 7mm and hood, use 14lb. Experience and body makeup make a big difference.
When the efficiency of wet cooling tower is lower than dry cooling tower?
1. In wet cooling tower Two phase flow heat trasfer 2. To remove sensible heat from water is very critical 3.It depends on water droplet size ,fills design,orientastion and climatical condition. But in dry cooling tower, Air is the only media to remove the heat from the source 1. In wet cooling tower Two phase flow heat trasfer 2. To remove sensible heat from water is very critical 3.It depends on water droplet size ,fills design,orientastion and climatical condition. But in dry cooling tower, Air is the only media to remove the heat from the source 1. In wet cooling tower Two phase flow heat trasfer 2. To remove sensible heat from water is very critical 3.It depends on water droplet size ,fills design,orientastion and climatical condition. But in dry cooling tower, Air is the only media to remove the heat from the source 1. In wet cooling tower Two phase flow heat trasfer 2. To remove sensible heat from water is very critical 3.It depends on water droplet size ,fills design,orientastion and climatical condition. But in dry cooling tower, Air is the only media to remove the heat from the source
Who invented the old fashioned water pump?
The first water pump was invented by the Mesopotamians in 3000B.C
Can a 230 v 1 np 60hz electric motor run safely with 380 v 3 phase?
SURE IF YOU WILL CONNECT IT CORRECTLY. 1. PROVIDE A SINGLE POLE CIRCUIT BREAKER- MINIMUM 16 AMP 2. CONNECT TO ANY PHASE (R,Y,B) - FROM CB TO THE FIRST TERMINAL OF THE MOTOR OR DOL STARTER IF AVAILABLE. 3. CONNECT THE SECOND TERMINAL IN THE NEUTRAL COPPER BUSBAR - USUALLY ARRANGED WITH TERMINAL BLOCK-UNINSULATED. 4. THIS CONNECTION IS NORMAL FOR COMMERCIAL AND INDUSTRIAL APPLICATION USING LINE TO NEUTRAL FOR SINGLE PHASE LOADS. 5. 220 V OR 230 V IS ATTAINED FROM: 380 V DIVIDED BY SQRT OF 3 6. EQUIPMENT VOLTAGE=230V -- CURRENT=4 AMP ( IF 95% EFF. AND 85% P.F.) 7. SYSTEM VOLTAGE=220V -- CURRENT=4.18 AMP (ACTUAL CURRENT) 8. REFERENCE FORMULA: EQUIP.VOLTAGE DIVIDED BY SYSTEM VOLTAGE X EQUIP. CURRENT.
we need vacuum to remove moisture from tank
What do you use to build an elevator?
To install an elevator, a vertical shaft has to be constructed. The approval of the design and the carpentry and electrical work should be done by the building agency. The installation of the elevators should be done by the experienced professionals.
What is the composite technique by which an artistic work is assembled from various elements?
It is called collage.
* Mild (low carbon) steel: approximately 0.05-0.15% carbon content for low carbon steel and 0.16-0.29% carbon content for mild steel (e.g. AISI 1018 steel). Mild steel has a relatively low tensile strength, but it is cheap and malleable; surface hardness can be increased through carburizing. * Medium carbon steel: approximately 0.30-0.59% carbon content(e.g. AISI 1040 steel). Balances ductility and strength and has good wear resistance; used for large parts, forging and automotive components. * High carbon steel: approximately 0.6-0.99% carbon content. Very strong, used for springs and high-strength wires. * Ultra-high carbon steel: approximately 1.0-2.0% carbon content. Steels that can be tempered to great hardness. Used for special purposes like (non-industrial-purpose) knives, axles or punches. Most steels with more than 1.2% carbon content are made using powder metallurgy and usually fall in the category of high alloy carbon steels.
Is ultrasonic sound can drill a hole through a hard metal or a mountain?
A drill operating at ultrasonic frequencies (>20 kHz) will usually employ a hard abrasive powder to actually do the drilling. The drill bit (which could be soft) vibrates back and forth at a high frequency, and grinds the substrate away with the abrasive.
What is the purpose of analysis?
1. It is a training plan for facilitating successful employment for the new employee.
2. It can be used as an accountability measure to ensure that the trainee's work is of highest quality possible.
3. It can be offer as a resource to the employer providing the job.
What is the difference between carbon steel fittings and malleable iron fittings?
Malleable iron has been in use for hundreds of years and is a good choice for small castings or castings with thin cross sections. Malleable iron can be bent easily and has very good fracture toughness in colder temperatures. Fittings made from carbon steel are made in a wide variety of sizes with lower carbon steel being easier to bend but having less strength than higher carbon steels.
no, drill bits do not have shear strength, so that technique would snap them. An end mill could do the job, or more practically, use a drill press, and plunge cut many holes, causing a slot in the material. Other option is use abrasives. A grinders, a cut off wheel, a carbide grinding bit etc to open the slot up to size
What is the difference between mechanical and chemical pulp?
in mechanical pulping we are generating pulp by mechanical based
in chemical pulping we are using chemicals to produce pulp
chem pulping two types,
soda(alkaline)
sulphite(acid)
Biomass means that it's made from natural materials. A great example, and a traditional one, is the thatch roof. Thatched roofs have been used for thousands of years. Traditionally they're made from leaves, grasses, reeds, and straw. Of course today's thatch options are a bit more sophisticated.
What are the portfolio sites for engineering projects?
An Engineering Portfolio is a website or document that highlights examples of your work and projects. ... Portfolios increases one's awareness of their skills and abilities; it is another way to connect in-and-out of classroom learning with real world applications. Show off your work, your projects, and your passions
Sample of a time and motion study?
Assembling any product (ex: u-clamp). This will allow you study the time while using a stopwatch and recording the time you need to do each and single step, as well as studying the motion using the Therbligs such as grasp, reach.. etc..