An LT step-down transformer changes one low-voltage supply to a lower one, for example 415 V to 230 V for lighting and controls, or 415 V to 110 V for imported equipment. A step-down transformer lowers voltage because its secondary winding has fewer turns than its primary.
What it is: 415 V down to 230 V, 110 V or as specified, 25 kVA to 2500 kVA, dry type or oil cooled.
Best suited for: Lighting, controls, imported equipment, separate LT circuits.
Changes one LT voltage to another, without touching the HT side.
Fixed ratio or off-circuit taps.
Available dry type or ONAN oil cooled.
Separates LT circuits, which limits fault spread between them.
Single or three phase, 50 Hz, copper wound.
| Parameter | LT Step-Down Transformer |
|---|---|
| Rating | 25 kVA to 2500 kVA |
| Primary voltage | 415 V or as specified |
| Secondary voltage | 230 V, 110 V or as specified |
| Phase and frequency | Single or three phase, 50 Hz |
| Vector group | As specified |
| Cooling | Dry type / ONAN |
| Winding | Copper |
| Voltage regulation | Fixed or off-circuit taps |
| Impedance | As per design |
| Efficiency | As per design |
| Losses | As per design |
| Standards | IS 2026 / IS 11171 |
| Fittings | Terminal box, enclosure IP rating |
Off-circuit tap switch, Buchholz relay, oil and winding temperature indicators, cable box or bushings, and marshalling box are available as options. GA drawings, rating plate drawings and guaranteed technical particulars (GTP) are available on request.
Separate 230 V or 110 V supply for lighting or controls
Imported machine rated 380 V or 400 V
Imported machinery: 380 V, 400 V or 690 V equipment
Isolating one LT circuit from another
Our application engineers can size the unit for your load and supply. We also make servo voltage stabilizers, industrial rectifiers, chemical earthing electrodes for transformer neutral and body earthing, and lightning arresters for the substation.
More questions are answered on the transformers page, which covers kVA sizing, losses, testing and how to compare transformer manufacturers.
| Product | What it is | Best suited for |
|---|---|---|
| Distribution Transformer | Three phase, oil cooled (ONAN), 11/0.433 kV, 22/0.433 kV or 33/0.433 kV, 25 kVA to 500 kVA, step-lap CRGO core, copper wound | Utility-supplied factories, commercial buildings, housing, solar and pumping |
| HT AVR Transformer | Copper-wound “two-in-one” HT stabilizer and transformer for 11, 22 or 33 kV, holding the LT output within ±1%, for indoor or outdoor installation, 500 kVA to 10 MVA | Industrial plants on unstable HT supply, hospitals, data centres, process lines |
| LT Step-Up Transformer | 415 V up to 690 V or as specified, 25 kVA to 2500 kVA | Motors and machines rated above 415 V, long LT cable runs |
| Dry Type Transformer | Three phase, ventilated, cast resin or VPI, 11 kV or 33 kV class, 25 kVA to 500 kVA, oil-free and fire-safe | Indoor substations, high-rise buildings, hospitals, malls, metro and data centres where oil is a fire risk |
| Furnace Transformer | Heavy-duty transformer feeding medium-frequency induction furnace panels, 25 kVA to 500 kVA, built for high currents and frequent short circuits during melting | Steel melting shops, foundries and alloy plants |
Send your kVA rating, HT and LT voltages, vector group and site location. Our engineers will reply with a techno-commercial offer, guaranteed losses, a GA drawing and the delivery schedule.