Transformer & Inductor Design Examples

RALE Engineering  GmbH provides you with transformer & inductor design examples for typical small transformers, large transformers, toroidal transformers & inductors FOR FREE to help you save time and money.

Check them out and benefit from RALE’s know-how.

Below you will find design examples. We have also included the input files for almost each of the examples. You will find most of them at the top of each example. Just click.

Small Transformer Design Examples

These examples demonstrate how to design low-power and control transformers with RALE. Almost every design example includes the full input file, a PDF datasheet and winding layouts.

  1. Designing inherently short-circuit-proof, potted safety transformers up to 10VA with the Rale Design Software, in accordance with IEC 61558
  2. Design a not short-circuit-proof 18VA – low profile safety transformer as per IEC 61558, protected by a miniature fuse in accordance with IEC 127.
  3. Design a 60VA (long stack EI42/98) – non-inherently short-circuit proof safety transformer for halogen lamps in accordance with IEC 61558, protected by a thermal fuse
  4. Design a rectifier safety transformer for feed to voltage controllers of 5Vdc,1Adc and 2x12Vdc,0.1Adc with RC-loading accordance with IEC 61558
  5. Design a three-phase rectifier/safety transformer for 24Vdc, 80Adc with RC load, as per IEC 38 and IEC 61558
  6. Design a low inrush current universal control transformer for 800VA continuous output power as per IEC 61558
  7. Design an 8000VA transformer for medical premises in accordance with IEC 61558 
  8. Design a 50kHz, 1200VA transformer as per IEC 61558
  9. Design a 100kHz, universal flyback transformer for input voltage125-700Vdc and output power 200W
  10. Design a 250kHz, 120W forward transformer with voltage controller, for input voltage range 200V to 350V, as per IEC 61558
  11. Design a low inrush current three phase universal autotransformer for 10kVA continuous output power as per IEC 61558
  12. Design a motor starting three-phase autotransformer for 100kVA continuous motor power as per IEC 61558
  13. Designing non-short-circuit-proof, low profile safety transformers up to 42VA with Rale Design System, in accordance with IEC 61558, protected by miniature fuse as per IEC 127
  14. Design a 50kHz, 240W resonance transformer for a LLC converter
  15. Design a split core current transformer 1000A/0.1A, 10V, 50Hz

Large Transformer Design Examples

These examples include rectifier transformers, distribution transformers, k-factor transformers, including oil-filled, dry-type constructions and such with indirect water cooling.

  1. Designing a 500 kVA, 50Hz, K-Factor 20, three phase dry transformer with litz & foil
  2. Designing a 3 phase, 50/60Hz rectifier transformer  (YYD) to suppress 5.and 7.current harmonics with 2 parallel connected bridge rectifiers for Udc=400V, Idc=1000A
  3. Designing a 12Vdc, 30kAdc Rectifier Transformer
  4. Designing a 1600kVA, Yyn, 50Hz Distribution Transformer – Input: 3x35kV+-10%, 85kV_50Hz_1min, BIL 120 kV, Cu discs; Output: 3x690V, 1340A, Cu foil 4×100//4×100 with oil tank AND Designing a 1600kVA, Yyn, 50Hz Distribution Transformer – Input: 3x35kV+-10%, 85kV_50Hz_1min, BIL 120kV, Cu multi layer, 8 sections with 7 layers; Output: 3x690V, 1340A, Cu foil 4×100//4×100 with oil tank
  5. Designing an autotransformer for  400Vdc, 1000Adc with 2 parallel connected rectifiers in 12-pulse operating mode
  6. Creating a 4 lines 3 phases net in a 3 lines 3 phases net using a Zn-transformer
  7. Creating the Inputs to Design Rectifier Transformers
  8. Designing 24 pulse rectifier 4 x 600Vdc/1000Adc with 2 dry Dext/YD transformers, driven by 3 x 6000V, 50 Hz
  9. Designing a 200kVA, Three Phase Transformer, 400V/400V,50 Hz, DY with Indirect Water Cooling
  10. Designing a non resonant high voltage, single phase, oil transformer class =<0.5%
    Input: 22kV, Test voltage 50kV, 50Hz_1min,BIL 100kV, Cu multi layer winding
    Output: 2x110V,1.45A,4 Cu -single layer windings with “S1/2-S2/2-P-Screen-S1/2-S2/2” order of windings

Toroidal Transformer Design Examples

Information for our customers: All single phase design examples (up to 10 kVA, 50/60 Hz) calculated with the Small Transformer Program can also be calculated with the Toroidal Transformer Program.

Inductor Design Examples

From smoothing chokes to power factor correction chokes and drainage chokes  — check them out.

  1. Designing Motor Filter Chokes
  2. Single Phase, 25mH Common Mode Choke in 50 Hz net for suppressing up to 50 kHz current harmonics 
  3. Designing Power Factor Correction Chokes 
  4. Single Phase Commutation Choke
  5. Three Phase Commutation Choke
  6. Designing Smoothing Chokes
  7. Designing 3 Phase LC-Filter For Power Factor Correction, 50kVAr, parallel to Rectifier Bridge
  8. Single Phase, 25mH Common Mode Choke in 50Hz net for suppressing up to 50kHz current harmonics
  9. Drainage Choke between 2 parallel connected rectifiers 2x(24Vdc,500Adc) at 50Hz to support good DC current distribution and limit 150Hz current harmonic
  1. Le Blanc Transformer
  2. Scott Transformer
  3. V/ZZ Transformer
  4. Designing a Constant Voltage Stabilizer 2000W, 1000V +-20%/11V+-1%,50Hz short circuit proof
  5. CCT

Download PDF booklet (Chicago 2008)

Want them offline? Download our free PDF booklet containing 13 fully documented design examples in US UNITS (assembled by Pamela and Dan – our representatives for USA and Canada).