Voltage Drop and Battery Calculations

Voltage drop is actually the electrical potential decrement along the current path flowing mainly in the electrical circuit. As we know, copper wires are the perfect conductors; they have a small resistance amount. According to Ohm’s Law, voltage is equal to the current which is actually multiplied by the resistance. V=I*R. This means that in the wires, the small voltage amount is actually lost as the current flows through the electrical system. This is called the voltage drop. If the current is more along with the higher resistance wire, this results in a higher voltage drop.

Calculations

It is a complicated process to calculate the accurate voltage drop in the electrical system. This mainly depends on the wire resistance, wire length, temperature and current type (whether DC or AC). If you get a close estimate, it is sufficient and simple enough in all applications. 

It is necessary to note that the formula of voltage drop changes depending on the different phases in the circuit (single or three). In the equation the variables include:

Z = Conductor Impedance (Ohms/Kft, Ohms per 1000 feet)

I = Load current in amperes

L = Length in feet

Installation type       Formula for Voltage Drop

Single-phase                    V Drop = 2 x Z x I x L / 1000

Three-phase                     V Drop = 1.73 x Z x I X L / 1000

We actually divided formulas by 1000 because of the fact that the standard values of impedance are actually provided for 1000 feet. In this way, they are converted into the ohms per foot.

Voltage Drop Control

As we know, there is no accurate material and conductor that have electrical resistance, it seems impossible to annihilate the voltage drop. There are several ways to minimize the voltage drop.

Improvement of System Efficiency

If you assume the load, it should stay as it is and increasing the electrical equipment efficiency mainly helps to reduce the consumption of power. As the supply voltage is constant, the improvement in the efficiency mainly results in the reduction in voltage drop as well as less current.

Correct Size of Conductor

If you won’t select the proper conductor, then it can experience a significant drop in the voltage. If you are selecting a conductor, it is necessary for you to account for several factors such as ambient temperature, full current load and many conductors in the raceway.

Troubleshooting

It is a fact that most of the electrical issues cause an increase in the resistance, as well as current and this, actually leads to a higher voltage drop which is not safe. Once you resolved all these issues, the voltage drop comes to its normal state.

Balanced Load Distribution

Large buildings actually use the three-phase circuits which seem to have three conductors. Suppose, if one phase is loaded highly, it will definitely experience a large current and increase in the voltage drop as compared with other phases. 

Hence, there are different significant measures that can help to reduce the voltage drop. They include:

·      Decrease the load current

·      Increase in the conductor diameter

·      Decrease the length of the conductor

·      Decrease the temperature of the conductor

·      Increase the parallel conductors