Transformer kva Calculator

Transformer kva calculator

Transformers are static electrical equipment that is used to convert the voltage or current to different levels. The transformer can be rated by kVA (kilo Volt-Amps) or MVA (Mega Volt-Amp). Here kVA and MVA are the larger units that are used to indicate the bigger size of the transformer. By using this Transformer kva calculator we can get the current rating of the 3 phase and single phase transformer on the LT side(230v in 1-phase and 415 v in 3-phase) and HT side (11 kv). kva to amps calculator.

Transformer kva calculator

Select type of transformer and its kva rating then press calculate button to get transformer curent rating. calcualtor will provide current rating on lt side and ht side both.

FORMULAS USED IN Transformer kva calculator

Rating of a Single-phase transformer

Phase KVA = Volts x Amps / 1000
Phase Amps = KVA / Volts x 1000

Rating of a Three-phase transformer
Phase KVA = Volts x Amps x √3 / 1000
Phase Amps = KVA / Volts / √3 x 1000

Rating of a Three-phase transformer in kVA unit

KVA = (√3. V x I) /1000

How to size a transformer

  • Transformers are sized by determining the total load required (in amps).
  • Transformer capacity is rated in KVA (kilo-volt-amperes).
  • The load voltage and load amps must be known to calculate KVA rating.
  • We do not recommend loading a transformer above 80% of its KVA rating. When the KVA rating has been calculated, divide that number by 0.8 to get the minimum KVA rating needed. All values should be reviewed and confirmed by an electrician or electrical engineer.
  • The Transformer’s size is decided by the KVA of the load.
  • Load voltage, or secondary voltage, is the voltage needed to operate the load.
  • Line voltage, or primary voltage, is the voltage from the source.
  • Single-Phase has two lines of AC power.
  • Three-Phase has three lines of AC power, each line 120 degrees out of phase with the other two.
  • KVA is a kilovolt ampere or thousand-volt amperes. That is how transformers are rated.


By Transformer kva calculator any person can calculate amperage load on both LT ( 230 v in case of single phase transformer and 415 v in case of three phase system) and HT side(11 kv) only enetering kva rating of transformer.

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