Transformer Sizing Formula:
From: | To: |
Definition: This calculator determines the required transformer size in kVA based on the total electrical load, power factor, and system efficiency.
Purpose: It helps electrical engineers and technicians properly size transformers for safe and efficient power distribution.
The calculator uses the formula:
Where:
Explanation: The total load is divided by the product of power factor and efficiency to account for reactive power and system losses.
Details: Correct transformer sizing prevents overload conditions, ensures voltage stability, and optimizes energy efficiency while reducing equipment costs.
Tips: Enter the total load in kW, power factor (default 0.8), and efficiency (default 0.9). All values must be > 0, with PF and Efficiency ≤ 1.
Q1: What is a typical power factor value?
A: Industrial loads typically range from 0.7-0.9, while commercial buildings often have 0.85-0.95.
Q2: How do I determine system efficiency?
A: Transformer efficiency is usually 90-98%. Check manufacturer specifications or use 0.9 as a conservative estimate.
Q3: Should I add a safety margin?
A: Yes, it's common to add 10-25% to the calculated kVA for future expansion and safety.
Q4: What's the difference between kW and kVA?
A: kW is real power (what you pay for), while kVA is apparent power (what the transformer must supply).
Q5: How does this relate to three-phase systems?
A: This calculation works for both single and three-phase systems when using total kW load.