Cable cross section calculator
⚡ Calculation of transformer power in 3 steps
This tool helps engineers and electricians select equipment to avoid overloads. The calculation takes into account the type of network (1 or 3 phases) and energy losses.
- Enter the secondary voltage (Volts) and load current (Amps).
- Select the network type (single-phase 220V or three-phase 380V).
- Indicate the efficiency (usually 90-95%). If you need to calculate the exact percentage of losses manually, you will need percentage calculator.
What formulas are used?
For those who need a theoretical basis, our algorithm works according to classical electrical formulas:
- Apparent power (S):
V × I(for 1 phase) or√3 × V × I(for 3 phases). Measured in VA. - Active power (P):
S × (efficiency / 100). Measured in Watts (W). This is the “useful” power that the consumer will actually receive.
Frequently asked questions (FAQ)
🔹 What efficiency should be indicated if there are no documents?
For modern transformers, the standard value is the range 90-98%. If the equipment is old or you are not sure, set it to 90% to create a power reserve.
🔹 What is the difference between VA and W (Apparent and Active Power)?
Apparent power (VA) is all the energy circulating in the circuit (including useless reactive energy). Active power (W) is that part of the energy that does real work (heats, lights, rotates). Transformers are usually marked in VA (kVA).
🔹 Is the calculation suitable for an autotransformer?
Yes, the calculation method is identical. The main thing is to know the output parameters (voltage and current) of the secondary circuit.
Didn't find the tool you need? Look at the full list on site map.