Many people in the world are not aware of the difference between watts and VA. Both watts and volt-amperes are units of measurement for electrical power, where volt-amperes refer to apparent power and watts refer to real power drawn by the equipment. Each of these values provides information of electronic products on how much energy they draw or consume and the values show various purposes. The utility companies determine the watt rating and heat generated by the equipment. These both values can differ significantly and VA is always greater than or equal to watts. The ratio of watt and VA gives “power factor”, which is a very important factor in electricity measurement.
Let us discuss more differences between Watt and VA:
Watt: The watt ratings are useful whenever you need to get rid of the heat generated by the device that consumes watts and it is also used when you want to know how much you have to pay for the device’s utility company. To know the device total power, the real power of multiple DC or AC devices, you just have to add up the individual power ratings in watts of each device.
V-A: Volt-amperes provide the information about the amount of current drawn by a circuit in any product if you know the voltage. It is also used for properly sizing circuit breakers, wires and fuses. Though it cannot generate heat or electricity, but it is able to show the readings to know the values of all the electrical components with flowing electricity in it.
- The Instrument Needed for Measurement:
Watt: It is measured with wattmeter and also multimeter (A typical multimeter can measure watts unless both current and voltage must be DC).
V-A: A typical multi meter can measure V(R.M.S) and I(R.M.S), where VA = V(R.M.S) * I(R.M.S).
- Power Rating In UPS:
UPS has both maximum VA ratings and Watt ratings, which should not be exceeded. In Small UPS, the watt rating is approximately 60% of VA rating, whereas in large UPS, the watt and VA ratings are equal.
- Total Power in UPS Design:
Watts: The total effective power consumption of all connected devices should be less than the maximum effective power consumption of the UPS.
V-A: The total apparent power consumption of all connected devices should be less than the maximum apparent power consumption for the functioning of UPS.
- Computer Readings:
If a computer has the specification of power factor corrected which is commonly read as PFC, then the VA and Watt readings will be equal. For computers with non-PFC characteristics the watt reading is 0.55 to 0.75 times more than the VA reading.
From above differences it is clear that the watts is work done by any electrical source to generate heat or electricity whereas VA is the reading or information of the size wires, switches , fuses and many more electrical terms. An electrician Sydney cbd is well aware of all these terms and their differences.
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