Copper loss, or I²R loss, refers to the power loss caused by the resistance of copper windings in the electrical equipment such as

• **Transformers**,

• **Motors,** and

## Copper Loss Formula

It is calculated using the following formula:

**Copper loss = I2 x R**

Where,

I - Current flowing through conductor (A), and

R - Conductor’s Resistance (in ohms).

## Steps for Calculating Copper Loss

**Step-1:** Measure or get the current that flows through the copper winding.

**Step-2:** Measure the resistance (R) of the copper winding. This can be measured using an ohmmeter or estimated using copper’s length, cross-sectional area, and resistivity.

**Step-3:** To calculate copper loss, use the following formula and substitute current and resistance values.

## Solved Example

Consider a transformer winding with resistance of 0.5Ω & a current of 10 amps flowing through it.

Current (I): 10A.

Resistance (R): 0.5 Ω.

Copper loss = 10 x 10 x 0.5

Copper loss = 100 x 0.5.

Copper loss = 50 watts.

Thus, the copper loss is 50W

Click here for more **Electrical Calculators**