Economics of power generation : Objective Question > Multiple Choice Questions ()
Unity PF, or % PF, is when kVA = kW. A lagging PF is any PF that is less than %, inductive kVAR, and is typical in commercial and. It stands for Kilo Volt Amperes and one KVA equals 1, Watts of power. a change in the Distribution Connection and Use of System Agreement (DCUSA). Identify the incorrect relation. (A) power factor = KW / kVA. (B) kW = kVA x power factor. (C) kVA x kW = power factor. (D) kVA = kW / power factor. Get Answer.
Thermal Power Station Fuel such as coal, oil, gas, peat, energy crops like willow is burned and the heat is used to boil water and generate steam at high pressure. The steam passes through pipes to a steam turbine and turns it at high speed. Again the steam turbine is connected to the shaft of an alternator, turning it and generating electricity.
How to convert VA to Watts and KVA to Kilowatts
Nuclear power stations are also thermal using the heat of nuclear fission to boil water and turn it into steam. In general, the voltage supply to your home is nominally or volts. Voltage in the USA is volts, but two "hots" are supplied to homes so that a volt supply is also available between the hots.
The higher voltage is used for high powered appliances such as washers, driers, kitchen ranges cookers and air conditioning. It is also safer because in the event of an electrical shock, less current flows through the body so there is a lesser risk of electrocution. In countries where volts is standard, generators or step down isolating transformers are used to provide a volt supply for power tools.
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This is normally mandatory on construction sites. Again the idea of the lower voltage is to lessen the danger of electrocution, if for example a power flex is inadvertently cut, or a tool gets wet. Utility voltage by country.
Source How to Convert Between Volts, Amps and Watts We will consider Ohm's law later, but first let's examine the quantities which are usually of interest when dealing with appliances, such as volts, amps and watts and how to convert between them. If you look at the casing of an appliance see photo below you can usually find a specification label or panel which indicates the voltage supply, frequency, wattage and possibly current.
On some appliances e. TVs and washing machines, this panel may be mounted at the back of the device. So here are three simple equations for converting between volts, watts and amps: A volt appliance takes 2 amps, what is the power?Why transformer ratting in KVA (hindi)
A volt appliance consumes watts of power, How much current does it draw? A watt appliance draws 3 amps, What voltage is it running on? Notice I have chosen values in the examples so that everything works out nicely. You only really need to remember the first equation and if you know basic algebra you can rearrange to give the other two equations.
What kVA means and its important charges | Great Annual Savings
However as you can see, you always need to know two of the quantities before you can work out the third quantity. From looking at the Google Analytics statistics and the questions which land people on this webpage, I often see questions asked such as "how many watts are in volts?
The standard unit of energy is the joule or calorie, but generally energy used in the home is measured in kWh, also known as "units". To work out the number of kwh, you divide the power in watts by to convert to kilowatt kW and then multiply by time in hours to give kWh. Your electricity meter counts and displays the number of units used by all the appliances and lighting in your home. A watt drier runs for 3 hours a day, how many kWh does it consume and if electricity costs 12c per unit, what is the cost of running it?
Examples are devices controlled by a thermostat such as refrigerators, freezers, ovens in cookers and air conditioning systems. The time for which the appliance is powered on and consuming power is called the duty cycle and it is often quoted as a percentage.
This article gives a comprehensive list of domestic appliances and their energy use: What is the Cost of Running Electrical Appliances?
Calculating Power Consumption of Household Appliances My other article gives a comprehensive list of appliances, their power consumption and how much it costs to run them per hour: A kilowatt hour meter counts the number of units of energy you've used. Typically for a volt supply to a home, the main fuse rating is 80 to amps at the consumer unit. So this is the maximum current that will flow before the fuse blows. Just as an engine's mechanical output can be measured in horsepower, so can the mechanical output of an electric motor.
What Are Fuses For? As we will see later, electrical cables, appliances, wires inside appliances, components etc all have resistance. This resistance produces heat when current flows through it. Any electrical conductor can get excessively hot if too much current flows and in the case of wires, this can cause the plastic insulation covering the cable to melt or even catch fire. So fuses are used in series with a cable or appliance to limit current flow and make everything safe.
Fuses are like a "weak link" in a chain and blow before damage can occur.
They have a specified rating and this is not the current they blow at, but the current they will carry without blowing.
Once current exceeds the rating of the fuse, the fuse will blow. The length of time it takes for the fuse to blow is proportional to the current. So minor overloads can result in a fuse blowing in minutes, but if there is a large current or short circuit scenario, the fuse will blow in seconds or milli-seconds. This is not advisable, as there is no direct link between kVA requirement and annual energy usage.
For example, two businesses may both consumekWh per year.
Power Generation Economics : Multiple Choice Questions
One may run an item of equipment with a large power requirement for an hour a day and the other may use less powerful equipment for longer. Although they both use the same amount of energy, the first business requires more power because there will be more energy transferred to the building in a shorter space of time. This data will let you know how much electricity your building draws at peak usage and, hence, what kVA the meter needs to be.
If you have your half hourly data, you have the tools to figure it out. Remember, any business can install a half hourly meter, regardless of legislation. Contact us if you need some help with this. What happens if you exceed your kVA? In short, it can be serious. In a worst-case scenario, you could actually overload the supply, leaving you with no electricity until the costly repairs can be made.
For a business, this is going to hit you hard in the pocket.