Passive Components Blog
No Result
View All Result
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

    Sumida Announces New DC Common Mode Choke Coil Series

    KYOCERA AVX Releases New 3dB Hybrid Couplers

    SCHURTER Unveils High Voltage Fuses for EV Applications

    YAGEO Releases First to Market 750V Aluminum Capacitors

    binder Introduces M9 Compact Circular Connector

    Smolteks CNF-MIM Capacitors Meet Thermal and Voltage Stability Industry Requirements

    Wk 26 Electronics Supply Chain Digest

    Learn How Supercapacitors Enhance Power System in Knowles eBook

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Accelerating Full Bridge LLC Resonant Converter Design with Frenetic AI

    Understanding Switched Capacitor Converters

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

    Sumida Announces New DC Common Mode Choke Coil Series

    KYOCERA AVX Releases New 3dB Hybrid Couplers

    SCHURTER Unveils High Voltage Fuses for EV Applications

    YAGEO Releases First to Market 750V Aluminum Capacitors

    binder Introduces M9 Compact Circular Connector

    Smolteks CNF-MIM Capacitors Meet Thermal and Voltage Stability Industry Requirements

    Wk 26 Electronics Supply Chain Digest

    Learn How Supercapacitors Enhance Power System in Knowles eBook

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Accelerating Full Bridge LLC Resonant Converter Design with Frenetic AI

    Understanding Switched Capacitor Converters

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
No Result
View All Result
Passive Components Blog
No Result
View All Result

Calculating for KVA in Single and Three Phase Transformers

4.4.2018
Reading Time: 2 mins read
A A

Source: Sensors online article

by Andrew Holland |Apr 3, 2018 1:37pm. Need to size a single or three-phase transformer? Transformer sizes are dictated by their respective KVA rating. Using common variables, one can compute for the required KVA rating or transformer size for a particular project, system or operation. This article provides basic formulas for finding the correct size of single and three-phase transformers using load voltage and load current.

RelatedPosts

TDK Increases Current Ratings of Automotive Thin-Film Power Inductors

Sumida Announces New DC Common Mode Choke Coil Series

KYOCERA AVX Releases New 3dB Hybrid Couplers

Single Phase KVA Calculation

The formula for finding the required KVA or transformer size for single-phase power is the following:

Volts x Amps / 1,000 = KVA

Based on the equation, one would need to plug in the proper load/output (secondary) voltage and current (amps) to compute for KVA. Note that load voltage is not the same as line voltage, which is also known as primary voltage or input.

Example: Find the KVA or transformer size for load voltage of 120V 1PH and a load current of 50A.

120 x 50 / 1,000 = KVA

6,000 / 1,000 = KVA

= 6 KVA

 

Three-phase KVA Calculation

Businesses that require three-phase power need to add an extra component in the formula to arrive at the correct transformer size, i.e., square root of 3 (√3) or 1.732. This figure is a constant found in three phase, as the phases do not generate the same amount of power (simultaneously). Furthermore, three-phase transformers handle three lines of AC power, with each of the three lines 120 degrees out of phase from the other two lines.

With this in mind, the new formula can be found below:

Volts x Amps x √3 / 1,000 = KVA

Example: Find the KVA or transformer size for load voltage of 240 3PH and a load current of 60 amps.

240 x 60 x 1.732 / 1,000 = KVA

= 24.94 KVA (or 25 KVA after rounding up)

 

Future Expansion and Standard Transformer Sizes

Computing for the required KVA is not the final step in determining the proper transformer size. Most computations (especially for three-phase loads) do not provide a whole number. As a result, the value must be rounded up, as seen in the sample above. It is best practice to always round up and not down.

Next, in order to factor in future expansion and prevent risks associated with accidental overloading, one should add 20 percent of spare capacity. Taking the three-phase sample again, we simply add 20 percent to the rounded figure:

25 KVA + 5 = 30 KVA

Lastly, one may find that the specific transformer size needed is not being offered or is unavailable by the store or preferred manufacturer. In most cases, this is because there are standard KVA sizes for transformers. If you cannot find the size you need, simply round up again to the next standard KVA size.

For referencing, the standard KVA sizes for singe-phase transformers are 1, 1.5, 2, 3, 5, 7.5, 10, 15, 25, 37.5, 50, 75, 100, 167, 200, 250 and 333 KVA

Taking our answer from the single-phase example above – 6 KVA or 7.2 KVA (with 20% spare capacity); we can see that there is no standard single-phase equivalent available. As a solution, simply round up to the next standard single-phase KVA size: 7.5 KVA.

Standard sizes for three-phase transformers are 3, 6, 9, 15, 30, 45, 75, 112.5, 150, 225, 300, 500, 750 and 1,000 KVA

Taking our final three-phase figure of 30 KVA, we can see that it matches with a standard three-phase transformer size above, i.e., 30 KVA. No further rounding or conversion is needed, since 30 KVA is a standard three-phase transformer size.

Related

Recent Posts

Advancements and Applications of Switch Capacitor Power Converters

25.6.2025
30

Samsung Delivers Silicon Capacitors to Marwell AI Systems

24.6.2025
57

Smoltek CNF-MIM Capacitor Commercialization Update

11.6.2025
35

Understanding Switched Capacitor Converters

9.6.2025
91

Capacitance Definition of Non-Linear Voltage Dependent Capacitors

5.6.2025
46

Coupled Inductors Circuit Model and Examples of its Applications

21.5.2025
149

Capacitor Ripple Current Testing: A Design Consideration

21.5.2025
104

How to design a 60W Flyback Transformer

12.5.2025
98

Modeling and Simulation of Leakage Inductance

9.5.2025
71

Murata and NIMS Built New Database of Dielectric Material Properties

5.5.2025
101

Upcoming Events

Jul 23
13:00 - 14:00 CEST

PCB design for a Smartwatch

Jul 29
16:00 - 17:00 CEST

Impact of Elevated Voltage and Temperature on Molded Power Inductors in DC/DC converters

View Calendar

Popular Posts

  • Buck Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Boost Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Flyback Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • What is a Dielectric Constant and DF of Plastic Materials?

    4 shares
    Share 4 Tweet 0
  • LLC Resonant Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Ripple Current and its Effects on the Performance of Capacitors

    3 shares
    Share 3 Tweet 0
  • How to Design an Inductor

    0 shares
    Share 0 Tweet 0
  • Dual Active Bridge (DAB) Topology Explained

    0 shares
    Share 0 Tweet 0
  • SEPIC Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Why Low ESR Matters in Capacitor Design

    0 shares
    Share 0 Tweet 0

Newsletter Subscription

 

Passive Components Blog

© EPCI - Leading Passive Components Educational and Information Site

  • Home
  • Privacy Policy
  • EPCI Membership & Advertisement
  • About

No Result
View All Result
  • Home
  • Knowledge Blog
  • Premium Suppliers

© EPCI - Leading Passive Components Educational and Information Site

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.
Go to mobile version