How to Calculate Kva to Amp

••• dimamorgan12/iStock/GettyImages

In electromagnetic physics, a ​volt-ampere,​ the notation for which is VA, is a measure of apparent power and uses watts for units. For some problems, you may be required to determine the current, I, flowing through a circuit and measured in amperes. If so, you may be given the value of this apparent power, often provided in kilo-volt-amperes, or kVA.

The equation you need for such problems is:

S=VI

Where S is apparent power – sometimes the same as actual power, as in the case of a purely resistive circuit, but usually less – V is the potential difference in volts and I is the current in amperage. Since power, as mentioned, can be equivalently expressed in watts or volt-amperes, you can see that the units match up.

One wrinkle is that the equation needs to be modified in the case of three-phase systems. In these instances, a constant multiplying factor of √3 must be appended to the right-hand side.

To convert from kVA to amperes:

Step 1: Determine the Phase of the System

For single-phase systems, use S = V × I. For three-phase systems, use:

S=\sqrt{3}VI

Assume for this sample problem that you are addressing a three-phase system with an apparent power of 100 kVA and a potential difference of 50 V.

Step 2: Determine the Current in Kiloamperes

Solve the equation using the specified values of S and V:

100=\sqrt{3}\times 50\times I\implies I=\frac{100}{\sqrt{3}\times 50}=1.155\text{ kiloamperes}

Step 3: Convert From Kiloamperes to Amperes

Since 1 kA = 1,000 A, 1.155 kA = 1,155 A.

Related Articles

How to Calculate Three Phase Amps From Megawatts
How to Convert KVA to KW 3-Phase
How to Calculate KVA from KW
How to Convert HP to Amps & Volts
How to Calculate DC Voltage
How to Calculate Transformer VA Rating
How to Calculate 3-Phase Line-To-Ground Voltage
How to Find Resistance With Power & Voltage
How to Convert BTU to Horsepower
How to Change Electrical Amps to Watts
How to Convert Megawatts to Amps
How to Calculate 3 Phase Power
What Would a 60-Watt Solar Panel Run?
How to Calculate CT Ratio
How to Calculate a KVA Rating
How to Convert 12 Volt Alternator to 120 Volts
How to Calculate Power Rating
How to Convert mW to mA
Definition of KAIC
How to Calculate Dynamo Power Amps