Common Refrigerator Test-Bed Voltage, Current, and Power Plots – Alexander Feldman's Blog
There is a very simple calculation equation for computing watt usage for an The multiplication formula is voltage multiplied by current, expressed as W=V X I.. that list the watts used by various appliances, from refrigerators to boom boxes. (the appliance's electric CURRENT) × (the VOLTAGE across its terminals). For example From this equation, it is clear that higher power appliances bulb, vacuum cleaner, refrigerator, electric toothbrush, radio, computer, portable electric. Appliances built for use in North America are designed to operate on VAC (Volts Alternating Current). Most of the world, however, operates on.
Examples of DC sources are batteries, DC generators known as dynamos, solar cells and thermocouples. AC This stands for "alternating current" and means that the current "alternates" or changes direction. So current flows one way, reaches a peak, falls to zero, changes direction, reaches a peak and then falls back to zero again before the whole cycle is repeated. The number of times this cycle happens per second is called the frequency.
In other countries it is 50 Hz. The electricity supply in your home is AC. The advantage of AC is the ease by which it can be transformed from one voltage level to another by a device known as a transformer. AC sources include the electrical supply to your home, generators in power stations, transformers, DC to AC inverters allowing you to power appliances from the cigarette lighter in your carsignal generators and variable frequency drives for controlling the speed of motors.
The alternator in a vehicle generates electricity as AC before it is rectified and converted to DC. New generation brushless, cordless drills convert the DC voltage of the battery to AC for driving the motor. Reducing Costs of Transmitting Electricity Over the Grid Because AC can so easily be transformed from one voltage to another, it is more advantageous for power transmission over the electricity grid.
Generators in power stations output a relatively low voltage, typically 10, volts. Transformers can then step this up to a higher voltage, ,volts or higher for transmission through the country. A step up transformer, converts the input power to a higher voltage, lower current output.
Now this decrease in current is the desired effect for two reasons.
How to Calculate Wattage (Formula and Tools) - wikiHow
Power is wasted as heat in transmission cables, which obviously isn't wanted. The AC waveform of the the domestic supply to our homes is sinusoidal. Source Transformer in an electrical sub-station.
The function of a transformer is to either increase or decrease voltage. Source What is Three-Phase Voltage? Very long distance transmission lines may use DC to reduce losses, however power is normally distributed nationwide using a 3 phase system. Each phase is a sinusoidal AC voltage and each of the phases is separated by degrees.
So in the graph below, phase 1 is a sine wave, phase 2 lags by degrees and phase 3 lags by degrees or leads by degrees. Only 3 wires are needed to transmit power because it turns out that no current flows in the neutral for a balanced load. The transformer supplying your home, has 3 phase lines as input and the output is a star source so it provides 3 phase lines plus neutral. In countries such as the UK, homes are fed by one of the phases plus a neutral. In the US, one of the phases is split to provide the two 'hot' legs of the supply.
Why Is 3 Phase Used? More power can be transmitted using just 1. The incoming supply is typically 11kv and output phase voltage is volts in countries which use this voltage 3 Phase voltages. Each phase is sinusoidal with a phase difference of degrees.
Source Delta-Star Wye transformer which can supply single or 3-phase supply. Source Three-phase power lines. Each overhead line is a single phase. If you live in the United Statesthe power outlets in the wall of your house or apartment deliver volts each.
Common Refrigerator Test-Bed Voltage, Current, and Power Plots
If you know the amps and volts involved, you can determine the amount of electricity consumed, which we typically measure in watt-hours or kilowatt-hours. Imagine that you plug a space heater into a wall outlet. You measure the amount of current flowing from the wall outlet to the heater, and it comes out to 10 amps. That means that it is a 1,watt heater. If you multiply the volts by the amps, you get the wattage.
In this case, volts multiplied by 10 amps equals 1, watts. This holds true for any electrical appliance. If you plug in a light and it draws half an amp, it's a watt light bulb. Let's say that you turn on the space heater and then look at the power meter outside. The meter's purpose is to measure the amount of electricity flowing into your house so that the power company can bill you for it.
Let's assume -- we know it's unlikely -- that nothing else in the house is on, so the meter is measuring only the electricity used by the space heater. The refrigerator is empty and at the set-point temperature at the beginning of the experiment.
Relationship and Difference Between Voltage, Current and Resistance
The raw signal from which figure 1 is constructed contains values. During this one day experiment, the thermostat switches the compressor on and off 68 times. The mean time for the compressor being on is The mean off-time of the compressor is The duty-cycle of the refrigerator for this experiment is Refrigerator test-bed current during a hour nominal experiment Refrigerators exhibit oscillatory behavior: Figure 2 shows a frequency plot of the signal shown in figure 1.
The plot shows amplitudes in the frequency range The largest non-DC amplitude is at Hz. This frequency corresponds to a period of FFT plot of the refrigerator test-bed current during a hour nominal experiment Figure 3 gives us a closer look on the current signal during one compressor-on cycle.