Isolation transformer

3 Phase Electrical Power Isolation Transformer

A 3 phase transformer, there is a three-legged iron core as shown below. Each leg has a respective primary and secondary winding. Thus a 3 phase isolation transformers is a 3 phase transformer which has isolated primary and secondary windings to allow the power input to be isolated from the power output.

Isolation transformer

Standard 3 Phase Isolation Transformers

3 phase isolation transformers have 3 primary and 3 secondary windings that are physically separated from each other. Sometimes these isolation transformers are referred to as "insulated". This is because the windings are insulated from each other. In a 3 phase isolation transformer the output windings will be isolated, or floating from earth ground unless bonded at the time of installation.

Isolation transformer

General Purpose Isolation transformers

General Purpose Isolation transformers are used to lower distribution voltages (up to 750V) to lower voltages for power distribution within commercial or industrial buildings. These “two windings” transformers provide the electrical isolation required, and allow for short runs of high current, low voltage cables, reducing losses in the system, and reducing costs.

General Purpose Isolation transformer are suitable for supplying the following type of loads

  • General purpose lighting & electrical
  • Motors (without VFD controllers)
  • Resistive Heating

Drive Isolation Transformers

Drive Isolation Transformers are designed for supplying power to SCR (Silicon Control Rectifier) motor drives which provide convenient variable speed motor control and can save on energy.

A Drive Isolation Transformer (DIT) is designed specifically to supply power to VFDs. The isolation between the primary and secondary provides electrical isolation between the supply and the load. The transformer core is designed to handle the harmonic voltage without saturating, and the coils are braced to handle the mechanical forces that are introduced due to these harmonic currents. The coils are also designed to mitigate the impact of the harmonic currents. The winding conductors are selected and designed to keep eddy and stray losses to a minimum and the sufficient cooling is provided to dissipate the additional heat generated by the harmonic current.

Construction

  • Core and coil assemblies are mounted on isolation pads to reduce noise.
  • Bolted coil terminations suitable for copper or aluminium cables.
  • Front & back covers are easily removable for service.
  • Up to IP42 steel enclosures are available with paint / powder coating having lifting and wheel arrangement. MS or Stainless Steel enclosures are optional.
  • CE Certified
  • Qualified to the seismic requirements
  • Copper (Cu) or Aluminium (Al) windings
  • Copper / Aluminium / GI grounding strap
  • Accessible mounting flanges with front/back slotted mounting holes make installation easier
  • 100% Factory tested for shorts and coil integrity, current and loss, voltage, impedance and noise.
  • Clear, Comprehensive Documentation and labelling
  • Separated windings
  • With more severe requirements on test voltages and creep age distance and clearance in air because these transformers are often exposed to overvoltage.
  • Input-side matching taps.
  • Connections to safe-to-touch screw / screw less terminals in accordance with IEC61558 / IEC60076
  • Additional clamp type terminal on request.
  • High-grade, vacuum impregnation in polyester impregnating resin.
  • Special versions available on request.

Specification

  • Output VA range

    0.5KVA to 5000KVA

  • Input voltage

    Max. 750V

  • Output voltage

    Max. 750V

  • Frequency

    50 / 60 Hz

  • Vector group

    Dyn11 / Dyn5 (Special Are available on request)

  • Protection index

    IP00 max IP23 ( Other Available on special Request )

  • Insulation class

    F / H

  • Ambient temperature

    Max. 50 Degc

  • Efficiency

    90 to 99 % ( over a range of capacity)

  • Reference Standards

    IEC61558-2-2 /IEC60076 / IS2026 / IS11171

KVA Length Width Height X Y SLOT Weight Figure
0.5 180 125 200 160 90 8X20 11 A
0.75 240 121 240 160 75 8X20 13 A
1 240 120 240 160 75 8X20 14 A
1.25 240 135 240 160 90 8X20 19 A
1.5 240 145 240 160 100 8X20 21 A
2 300 150 300 180 90 10X25 26 A
2.5 300 160 300 180 100 10X25 30 A
3 300 170 300 180 110 10X25 34 A
4 300 180 300 180 120 10X25 41 A
5 360 200 360 200 135 13X28 53 A
6 360 210 360 200 145 13X28 61 A
7.5 360 210 360 200 145 13X28 65 A
10 360 215 360 200 150 13X28 72 A
12.5 360 215 360 200 150 13X28 83 A
16 420 250 420 220 170 13X28 110 A
20 420 260 420 220 180 13X28 127 A
25 480 285 460 220 200 13X28 161 A
30 520 315 520 220 200 13X28 201 A
35 520 315 520 220 205 13X28 222 A
40 550 320 550 220 210 13X28 232 A
45 550 350 550 220 210 13X28 261 A
50 550 400 550 220 265 13X28 260 A
60 600 400 600 400 270 17x35 285 B
75 600 500 600 400 265 17x35 329 B
100 600 500 600 400 270 17x35 400 B
125 750 450 700 400 240 17x35 500 B
150 750 450 700 400 240 17x35 550 B
200 1050 500 950 300-300 400 17x35 750 C
250 1200 500 950 350-350 400 17x35 825 C
300 1200 500 950 350-350 400 17x35 900 C
400 1250 600 1050 400-400 400 17x35 1200 C
500 1400 600 1050 400-400 500 17x35 1450 C
750 1500 700 1200 450-450 500 17x35 1650 C
1000 1620 990 1500 450-450 500 17x35 2100 C
1250 1800 990 1500 450-450 500 17x35 2800 C

Note:

For higher rating (>1000KVA) contact us for more details.

Dimension may change at the time of final design.

Figure For Type :- A

Isolation transformer applicable

Figure For Type :- B

Isolation transformer applicable

Figure For Type :- C

Isolation transformer applicable