Written and reviewed by the SG Power technical team at SG Power Products Pvt. Ltd. | Last updated: 6 November 2026
Among 400 kVA servo stabilizer manufacturers in India, SG Power Products Pvt. Ltd. makes the three-phase 400 kVA oil cooled servo stabilizer in its own Ghaziabad factory. Each unit holds the output within ±1% when the mains rises or falls. It safely runs about 256 kW of connected load.
As 400 kVA servo stabilizer suppliers in Noida, we sell direct, not through traders. A 400 kVA unit sits between our 250 kVA and 500 kVA models and is a high-capacity unit built for large plants and buildings on round-the-clock duty. Factory owners, hospitals, malls, campuses, EPC contractors and consultants across India buy from us at factory prices.
In short, SG Power’s 400 kVA servo stabilizer is a three-phase, oil cooled KNEUTRON unit listed in its catalogue with a 170–280V per phase input. Its datasheet guarantees 410V phase-to-phase output within ±1% at 97% efficiency. It carries about 556 A per phase and safely runs about 256 kW.
| Brand | KNEUTRON, made by SG Power Products Pvt. Ltd. in India |
| Capacity | 400 kVA (320 kW at 0.8 power factor) |
| Safe running load | About 256 kW, with a 25% margin |
| Phase | Three phase |
| Current | About 556 A per phase at 415V |
| Cooling | Oil cooled (ONAN: oil natural, air natural) |
| Output | 410V ±1% phase to phase and 230V ±1% phase to neutral, 97% efficiency tested to IS 2026 (Part 1), 100% load continuously (SG Power datasheet) |
| Model | 400 kVA Oil Cooled, 170–280V per phase (SG Power datasheet); other input ranges on request |
| Price | On request |
| Supply | Across India, from Noida and the Ghaziabad factory; service in 127+ cities |
* Prices are indicative. For the latest price, contact SG Power.
Source: SG Power product catalogue (February 2026), the KNEUTRON servo stabilizer catalogue and SG Power's 400 kVA oil cooled datasheet. Load and current figures are calculated at 415V and a 0.8 power factor. Checked November 2026.
Buy your 400 kVA servo stabilizer direct from SG Power, the manufacturer that designs each unit, winds its transformers and tests it before dispatch. We can set its input range and design to suit your site. You also get factory pricing and free sizing from your load list.
| From SG Power (Manufacturer) | From a Trader or Reseller |
|---|---|
| Factory pricing, no middleman margin | Reseller margin added |
| Input range and design matched to your site voltage | Stock model, whatever is available |
| Sizing by the team that builds the unit | Advice varies by seller |
| Transformers and variacs wound and tested in-house | Source of parts often unknown |
| Every unit tested through 173 checkpoints | Testing depends on the source |
| Service network in 127+ cities | Depends on the reseller |
A 400 kVA servo stabilizer is an automatic voltage regulator rated to carry 400 kilovolt-amperes of load while holding the output steady through voltage fluctuation. A microcontroller senses the voltage, and a motor-driven variac (a variable autotransformer) and buck-boost transformer add or remove volts. SG Power's 400 kVA unit is three phase and oil cooled.
It is also called a 400 kVA servo voltage stabilizer, a 400 kVA servo controlled voltage stabilizer or a 400 kVA 3 phase servo stabilizer. Other names are a 400 kVA automatic voltage regulator (AVR), a servo voltage regulator or an industrial voltage stabilizer. Some buyers search for a 400kva stabilizer or spell it servo stabiliser. On GeM, the Government e-Marketplace, such units are listed as a servo motor operated automatic line voltage corrector. Each of the three phases has its own variac, buck-boost transformer and stepper motor. To see how the correction works step by step, read how a servo stabilizer works.
| Part of a 400 kVA Unit | What It Does |
|---|---|
| KNEUTRON microcontroller | Measures input and output voltage with true RMS sensing and decides the correction |
| AC stepper motor | Turns the variac of each phase in small, smooth steps |
| Variac (dimmer) | Sets how much correction each phase needs |
| Buck-boost transformer | Adds volts when the mains is low and removes them when it is high |
| Insulating oil | Cools and insulates the transformers |
| Steel tank | Holds the oil and passes heat to the surrounding air |
A 400 kVA servo stabilizer corrects slow, lasting voltage changes across a plant: low voltage by day, high voltage at night, and uneven voltage between phases. It cannot stop lightning spikes, power cuts or harmonics. Those need a surge protection device, a DG set or UPS, and a harmonic study.
| Voltage Problem | Common Cause | Corrected by a 400 kVA Servo Stabilizer? |
|---|---|---|
| Low voltage (sag) | Long or overloaded lines, large loads starting nearby, sites at the end of a line | Yes, within the input band |
| High voltage (swell) | Light load at night, on holidays and in rain, or sites close to a substation | Yes, within the input band |
| Unbalanced phases | Many users on one line, or single-phase loads spread unevenly | Yes, with an unbalanced design |
| Spikes and surges | Lightning and switching of large loads | No; fit a surge protection device |
| Power cuts | Grid or feeder failure | No; use a DG set or UPS |
| Harmonics | Drives, rectifiers and other non-linear loads | No; have a power analyser study done against limits such as IEEE 519 |
Large plants with many drives, rectifiers or UPS systems often have harmonic currents, a common power quality problem that heats transformers. SG Power’s catalogue also lists K-rated transformers (K1, K13 and K20), made to customer specification, which are designed to carry such currents; see our transformers range.
A 400 kVA servo stabilizer runs about 320 kW at its full kVA rating, at a 0.8 power factor. For daily use, keep the running load to about 256 kW, so a 25% margin covers motor starting current. Each phase then carries up to about 85 kW, and the unit draws about 556 A per phase.
| Figure | 400 kVA Three Phase |
|---|---|
| Full rating | 400 kVA, or about 320 kW at 0.8 power factor |
| Safe running load (25% margin) | About 256 kW |
| Running load per phase | About 85 kW |
| Full-load current | About 556 A per phase at 415V |
| Fits running loads from | About 160 kW to 256 kW |
Safe running load = 400 kVA × 0.8 power factor ÷ 1.25. Current = 400,000 ÷ (1.732 × 415).
Typical loads a 400 kVA unit can carry, within about 256 kW in total:
Large factory: a machine shop with many CNC machines, or an injection moulding, printing or packaging plant with compressors and chillers
Hospital: imaging, operation theatres, ICUs, lifts and central air conditioning
Mall, hotel or office complex: lifts, escalators, chillers or VRV systems, lighting and IT
Campus or institution: hostels, labs, pumps and building services on one LT feeder
To check whether 400 kVA is the right size, add the kW of every load that runs at the same time and divide by a 0.8 power factor. Then add a 25% margin and choose the next size up. A 400 kVA unit fits a running load of about 160 kW to 256 kW.
List the running load: add the kW of the machines, chillers and equipment that run together.
Convert kW to kVA: divide by 0.8.
Add a 25% margin: multiply by 1.25 for starting current and growth.
Choose the size: if the result is between 250 and 400 kVA, choose 400 kVA; above 400 kVA, choose 500 kVA.
Formula: Required kVA = running load (kW) ÷ 0.8 × 1.25
For example, a 200 kW running load needs 200 ÷ 0.8 × 1.25, or 312.5 kVA, so a 400 kVA servo voltage stabilizer fits. For more worked examples, see our guide on how to calculate servo stabilizer kVA.
For motors, size from the nameplate full-load current, which already includes motor efficiency; efficiency classes are set out in IS 12615, published by the Bureau of Indian Standards. Size the stabilizer on the load it protects, not on the rating of your distribution transformer.
Not sure which size fits? Send your load list, and we'll check it free.
Choose 250 kVA for running loads up to about 160 kW, 400 kVA for about 160 to 256 kW, and 500 kVA for up to about 320 kW. All three are SG Power oil cooled catalogue models. The 400 kVA unit fits large loads that are too big for 250 kVA but do not need 500 kVA.
| 250 kVA | 400 kVA | 500 kVA | |
|---|---|---|---|
| Safe running load | About 160 kW | About 256 kW | About 320 kW |
| Current per phase (415V) | About 348 A | About 556 A | About 696 A |
| Cooling | Oil cooled | Oil cooled | Oil cooled |
| Catalogue input band | 170–280V per phase | 170–280V per phase | 170–280V per phase |
Source: SG Power product catalogue (February 2026). Load and current calculated at 415V and 0.8 power factor.
When to choose 500 kVA instead: pick the 500 kVA oil cooled model if your load is close to 256 kW or large machines are planned within two years. It also suits plants with several large direct-on-line motors. For loads under about 160 kW, the 250 kVA unit is enough.
The 400 kVA servo stabilizer price depends on the input range, balanced or unbalanced design, oil quantity, protections and extras such as a bypass panel. Every 400 kVA unit is priced on request after a free load check. You get a written quote for the exact model, with oil, GST, freight and installation shown separately.
| SG Power Model | Phase | Price |
|---|---|---|
| 400 kVA oil cooled (170–280V per phase) | Three phase | Price on request |
| 400 kVA oil cooled, custom input range | Three phase | Price on request |
| 250 kVA oil cooled | Three phase | Price on request |
| 500 kVA oil cooled | Three phase | Price on request |
Oil, GST, freight and installation are shown separately in the quote. * Prices are indicative. For the latest price, contact SG Power.
When you compare a 400 kVA stabilizer price across sellers, check that every quote is for a three-phase, oil cooled servo unit. The input range, design, oil fill and switchgear should also match. SG Power does not publish a fixed 400 kVA price list, because each unit is built for its site.
Online 400 kVA prices vary widely because sellers list very different products under the same rating. Tank size, oil fill, input range and switchgear differ, and some listings show placeholder prices. Compare the full specification, not the headline price.
| What Differs Between Listings | Why It Matters |
|---|---|
| Oil quantity and tank size | More oil and a larger tank keep the unit cooler on 24×7 duty |
| Input voltage range | A wider range needs a larger transformer and more oil |
| Balanced or unbalanced design | Unbalanced units correct each phase separately |
| Input and bypass switchgear | A breaker and bypass panel at this rating add real cost |
| Regulation and efficiency | ±1% regulation and the efficiency figure, 97% tested to IS 2026 (Part 1), should be stated in writing |
| Correction speed | Listings checked in November 2026 range from about 12 to over 45 volts per second; faster correction protects motors in quick dips |
| GST, freight, unloading and installation | Some prices leave these out |
Some listings show prices far too low for a 400 kVA unit, and some even list “single phase” 400 kVA units, which are not practical at this rating.
Want a 400 kVA servo stabilizer price for your site? Share your load and lowest voltage, and we'll send a written quote.
One 400 kVA servo stabilizer on the main LT supply is simpler and usually costs less than two smaller units. Two units, such as two 200 kVA stabilizers on separate feeders, keep half the plant protected if one is under service. Choose by how critical your loads are and how your LT panel is split.
| One 400 kVA Unit | Two Smaller Units | |
|---|---|---|
| Where it fits | After the main incomer, before the LT panel | On separate outgoing feeders |
| Cost and space | Usually lower cost, one plinth | Two units, two plinths, more cabling |
| During service or a fault | Whole site on bypass | Only one feeder on bypass |
| Best for | Factories with one main load centre | Hospitals, data rooms and plants with critical and general feeders |
Tell us how your LT panel is arranged when you ask for a quote, and we’ll suggest one or two units.
SG Power’s 400 kVA oil cooled servo stabilizer datasheet guarantees a 170–280V per phase input, or 340–480V phase to phase, and holds the output at 410V phase to phase within ±1%. Where the voltage often falls below 170V on any phase, we build a 400 kVA wide range servo stabilizer to order.
| Model | Input Band per Phase | Phase to Phase | Choose This When |
|---|---|---|---|
| 400 kVA Oil Cooled | 170–280V | 340–480V | Voltage falls in the day or at the end of a long line, but rarely below 170V |
| 400 kVA, custom range | On request | On request | Your lowest recorded voltage is below 170V, or outside the standard band |
The catalogue allows any input range to customer specification, and the KNEUTRON catalogue also lists three-phase input bands of 295–465V and 340–460V phase to phase. Online listings often quote phase-to-phase bands such as 320–480V or 340–470V; compare them with the per-phase band the datasheet guarantees. Record your lowest and highest voltage on each phase for a few days, including nights and holidays, and share the readings when you ask for a quote.
Choose a balanced 400 kVA servo stabilizer when three-phase motors, compressors and machines load each phase equally. Choose an unbalanced servo stabilizer design when hospitals, malls, hotels or campuses have lighting, ACs and IT spread unevenly across the phases. SG Power makes the 400 kVA unit in both designs.
| Design | How It Corrects | Best For |
|---|---|---|
| Balanced | Corrects all three phases together | Factories, motors, compressors and production lines |
| Unbalanced | Corrects each phase on its own | Hospitals, malls, hotels and campuses with single-phase loads |
In an unbalanced building, size on the most heavily loaded phase. Each phase of a 400 kVA unit carries up to about 133 kVA, or about 85 kW with the 25% margin.
SG Power’s 400 kVA servo stabilizer specifications follow its KNEUTRON oil cooled range, and its datasheet gives the guaranteed technical particulars. The unit regulates the output within ±1% at 97% efficiency, with an adjustable output delay of 3 to 200 seconds. Any other input range can be built to customer specification to suit the site.
| Parameter | Specification |
|---|---|
| Rated capacity | 400 kVA, three phase, four wire (R/Y/B/N) |
| Input voltage | 340–480V phase to phase, 170–280V phase to neutral (SG Power datasheet); custom ranges on request |
| Output voltage | 410V ±1% phase to phase and 230V ±1% phase to neutral (SG Power datasheet); set point adjustable to 380, 400 or 415V |
| Full-load current | About 556 A per phase at 415V |
| Regulation | ±1% |
| Efficiency | 97%, tested as per IS 2026 (Part 1):1977 (SG Power datasheet) |
| Output frequency | 50 Hz ±3% |
| Output delay | 3–200 seconds, adjustable |
| Control | KNEUTRON microcontroller with a high sampling rate; true RMS sensing of input and output without a control transformer |
| Motor | High-efficiency, high-torque AC stepper motor |
| Transformers | Dimmer (variac) and buck-boost transformers rated for 100% load current; wound and tested in-house on grain-oriented silicon steel for low iron and no-load losses; built to IS 9815 (Part 1), IS 5142 and IS 2026 |
| Winding | Pure copper winding (SG Power datasheet) |
| Cooling | Oil cooled, transformers immersed in oil (ONAN) |
| Mounting | Floor mounting (SG Power datasheet) |
| Housing | Powder coated CRC sheet (SG Power datasheet) |
| Insulation resistance | Not less than 7 mega-ohms, tested at 500V DC (SG Power datasheet) |
| Leakage current | 32 micro-amperes under normal operating conditions, tested as per IS 302-1:1979 (SG Power datasheet) |
| Design | Balanced or unbalanced |
| Duty | 100% load, continuous |
| Test certification | NABL tested (SG Power datasheet) |
| Applicable standard | IS 9815 (Part 1)-1984 (SG Power datasheet) |
| Catalogue model | 400 kVA Oil Cooled, 170–280V per phase |
| Country of manufacture | Made in India, at SG Power’s Ghaziabad factory |
The rows marked “SG Power datasheet” are the guaranteed technical particulars from SG Power's 400 kVA oil cooled datasheet. Other values come from the KNEUTRON servo stabilizer catalogue. Features and specifications may change as the technology is improved, so the final values are confirmed in our quotation. The IS standards are published by the Bureau of Indian Standards.
Other oil cooled servo stabilizers: 60 kVA | 75 kVA | 100 kVA | 125 kVA | 150 kVA | 200 kVA | 250 kVA | 400 kVA | 500 kVA | View all oil cooled models | View all air cooled models
Every SG Power 400 kVA servo voltage stabilizer is a microcontroller-based digital servo stabilizer, with a KNEUTRON controller, a front-panel display and ±1% voltage regulation. Its protections cut off the output on over-voltage, under-voltage, overload, phase reversal and single phasing, with an adjustable time delay. Calibration is done on a touchpad.
The display shows phase-to-neutral and phase-to-phase voltage, frequency and the output current of each phase. Start, Stop and Menu keypads sit on the front panel. You can set the output voltage and input band, and choose manual or automatic start and stop.
| Protection | What It Guards Against |
|---|---|
| Over-voltage cut-off | High mains voltage reaching machines and equipment |
| Under-voltage cut-off | Very low voltage that overheats motors and compressors |
| Overload cut-off | Load above the set limit; the display shows “Overload”, and the output restarts once the load is reduced and Start is pressed |
| Output delay (3–200 seconds) | Compressor and motor damage when power returns after a cut |
| Trip time delay (variable settings) | Nuisance tripping on very short voltage swings |
| Phase reversal cut-off | Wrong phase sequence, which can run motors backwards; the display shows “Ph. Reversal”, and the unit restarts once two incoming phases are interchanged and Start is pressed |
| Single phasing protection | Loss of one phase, which can burn out three-phase motors |
Need a 400 kVA 3 phase servo stabilizer with a custom input range? We build it to your site conditions.
A 400 kVA servo stabilizer is oil cooled because its transformers carry about 556 A per phase, often round the clock. Insulating oil removes this heat far better than air, so the windings stay cooler under continuous load. SG Power’s air cooled range stops at 50 kVA, so every larger size, including 400 kVA, is oil cooled.
In an oil cooled servo stabilizer, the variacs and buck-boost transformers sit in insulating oil inside a steel tank. Warm oil rises, gives its heat to the tank walls and sinks again. This oil natural, air natural (ONAN) cooling needs no pumps or fans, which makes the unit a heavy-duty choice for continuous, 24×7 industrial use.
| Oil Cooling at 400 kVA | What It Means for You |
|---|---|
| Transformers immersed in oil (ONAN) | Windings stay cooler under continuous, near-full load |
| Sealed steel tank | Suits factories and hot, dusty or humid rooms, on 24×7 duty |
| Large, heavy, floor-standing unit | Needs a designed concrete plinth and lifting access |
| Oil in the tank | Needs monthly oil level and leak checks, plus a yearly oil test |
For a full comparison, see SG Power's oil cooled servo stabilizers and air cooled servo stabilizers.
A 400 kVA servo stabilizer corrects voltage on the LT side, after your transformer, for the loads it feeds. An HT AVR transformer corrects voltage on the HT side, at the transformer itself, for the whole plant. Plants that take an HT supply and see wide voltage swings on every feeder sometimes choose the HT AVR route instead.
| 400 kVA Servo Stabilizer (LT) | HT AVR Transformer | |
|---|---|---|
| Where it sits | After the distribution transformer, before the LT panel | At the HT incoming supply |
| What it protects | The loads it feeds | The whole plant, including the transformer |
| Best for | LT consumers, or HT plants where one load centre needs correction | Large HT plants with voltage problems on every feeder |
SG Power’s KNEUTRON catalogue lists distribution transformers from 63 kVA to 2000 kVA, so one maker can supply the transformer and the stabilizer. For indoor substations, SG Power also makes dry-type transformers. Read more on SG Power's HT AVR transformer and distribution transformers, or ask us to compare both for your plant.
Place a 400 kVA oil cooled stabilizer in a dry, ventilated electrical room or covered substation yard, on a level concrete plinth, close to the main LT panel. Keep it away from rain, direct sun and flammable materials. Plan lifting and access before delivery, because the unit is large and heavy.
| Do | Avoid |
|---|---|
| A ventilated electrical room, substation room or covered yard | Open areas exposed to rain and direct sun |
| A level concrete plinth designed for the full weight with oil | Uneven or weak floors |
| Clear space around the tank for airflow and servicing | Walls or stored items pressed against the tank |
| A spot next to the main LT panel to keep heavy cable runs short | Long cable runs that add voltage drop and cost |
| Crane or forklift access, and a door and route wide enough for the unit | Narrow doors, ramps or basements without a lifting plan |
| A fire extinguisher suitable for electrical and oil fires nearby | Flammable materials, fuel or waste stored close by |
For reference, 400 kVA oil cooled units listed online weigh roughly 1.2 to 1.8 tonnes, depending on input range and design (listings checked November 2026). SG Power confirms the dimensions, weight and oil quantity of your model in the quotation, so you can design the plinth in advance.
Planning the electrical room? We'll share the dimensions and layout for your 400 kVA model.
A 400 kVA servo stabilizer is used where a large plant or building needs one unit for most of its LT load, often on round-the-clock duty. It protects factories, hospitals, malls, hotels and campuses from high and low voltage, voltage dips during motor starts, and damage to motors, chillers and controls.
| Application | What It Protects |
|---|---|
| Large factories and engineering units | CNC machines, VMCs, presses, compressors and production lines |
| Plastics, printing and packaging plants | Injection moulding machines, printing presses and packaging lines |
| Textile, pharmaceutical, rubber and paper units | Spinning and weaving machines, process lines, mixers and controls |
| Flour mills, rice mills and cement units | Motors, grinders and conveyors in dusty rooms, where oil cooling helps |
| Hospitals and medical colleges | Imaging, operation theatres, ICUs, lifts and central air conditioning |
| Malls, hotels and office complexes | Chillers, VRV systems, lifts, escalators, lighting and IT |
| Cold storage and food processing | Compressors, refrigeration plants and processing lines |
| Water bottling and pumping stations | Pumps, fillers and motor control panels |
| Campuses, institutions and research centres | Hostels, labs, scientific equipment and building services |
| Lifts and SCADA-based systems | Lift controllers, PLCs and automation panels |
| Telecom, IT and automobile units | Telecom equipment, server rooms and workshop machines |
SG Power’s catalogue lists customised engineering for cold storage, water bottling plants, CNC machines, SCADA-based systems, hospitals, malls and institutions, and lifts. Electrical contractors, EPC companies and consultants also buy 400 kVA units from us for projects that need several stabilizers across plants or buildings.
Have a qualified electrical contractor install the 400 kVA stabilizer on the main LT supply, after the transformer or DG changeover and before the LT distribution panel. Check the oil level before first power-on, connect proper earthing and book a yearly service. Regular oil checks keep the unit cool and accurate.
Size the input breaker, bypass arrangement and cables for about 556 A per phase, allowing for higher input current at low voltage; at this rating, parallel cable runs or a bus duct are common
Connect the tank and body to the earthing system, with earthing rods, earthing clamps, earthing strips and an earth pit cover, adding earth enhancing compound in dry or rocky soil; earthing practice is set out in IS 3043
Make permanent earth joints by exothermic welding, which suits the heavy conductors used at large plants
Follow the CEA (Measures relating to Safety and Electric Supply) Regulations, 2023 for the installation and earthing work
Run the heavy power cables on a cable tray, with trefoil clamps for single-core cables
Fit surge protection devices ahead of the stabilizer, and lightning protection where needed
Connect any UPS after the stabilizer, never before it
A servo stabilizer gives no electrical isolation; where equipment needs it, add an isolation transformer from SG Power's transformers range, which the catalogue lists from 10 kVA to 2000 kVA
Use the bypass only during servicing; equipment is unprotected in bypass
| Task | How Often | Who |
|---|---|---|
| Check input and output readings on each phase | Daily or weekly | Plant electrician |
| Check oil level and look for leaks | Monthly | Plant electrician |
| Check cable terminations for heating marks | Every 6 months, ideally with a thermal camera | Electrician |
| Test oil condition (breakdown voltage) and top up or filter | Yearly, or as advised | Trained technician |
| Inspect and replace worn carbon brushes | Yearly, or if correction slows | Trained technician |
| Full service and calibration | Yearly, or under an AMC | SG Power service |
Top up only with clean transformer oil (mineral oil). New mineral insulating oil in India is covered by IS 335, and the general properties of transformer oil explain why moisture and dirt must be kept out. For wiring and placement in detail, see the servo stabilizer installation guide.
Indian plant engineers and electricians on forums such as TechEnclave, HiFiVision and Team-BHP share lessons that apply to 400 kVA and other large three-phase stabilizers. Measure each phase over several days, leave headroom for motor starting, keep heaters off the stabilized line, and choose a supplier with quick local service.
| Common Concern | What to Do |
|---|---|
| Voltage on one phase falls much lower than the others | Record each phase in the morning, evening and night for a few days, and ask for an unbalanced design or a custom input range |
| Motors and compressors trip when the voltage dips | Size with a 25% margin for starting current, and set the output delay so compressors restart only after the voltage settles |
| Heaters, ovens and furnaces push the size and cost up | Wire resistive loads on a separate, unstabilized feeder |
| High voltage lasts for hours after a line or neutral fault and burns equipment | Surge devices absorb only short spikes; the stabilizer’s over-voltage cut-off disconnects the load when input stays above the band, so use both |
| The output hunts back and forth before it settles | Often a sign of a unit far larger than its load, or of a worn carbon brush; size on the real running load and have it calibrated at the yearly service |
| A short click or hum each time the voltage changes | This is normal, as the servo motor turns the variac; place the unit in a separate electrical room |
| A stabilizer keeps failing at one site | Have the supply checked with a power analyser for harmonics and a loose neutral before replacing parts |
| A failed unit leaves the whole plant unprotected | Choose a supplier with local service and spares, keep a bypass for use until service arrives, or split the load across two units |
Forum threads checked November 2026. Prices and brand names from the threads are not used here.
Facing low voltage or frequent trips at your plant? Share your readings and load list, and we'll size the unit.
To choose between 400 kVA servo stabilizer manufacturers and suppliers, first confirm that the unit suits your load, room, LT panel and lowest site voltage. Then compare regulation, efficiency, protections, oil fill, in-house manufacturing, testing and local service. Ask every seller the same questions, in writing.
Do you manufacture the 400 kVA unit, or resell another company’s model?
Is it three phase and oil cooled, and what input range does it cover?
Is it balanced or unbalanced?
What regulation and efficiency does it give, in writing?
Which protections and time delay are included?
Are the transformers and variacs made and tested in-house?
What are the size, weight and oil quantity?
What is the correction speed, in volts per second, and the maximum ambient temperature?
Will you share a datasheet, a general arrangement (GA) drawing and a routine test report?
Are the input breaker, bypass, oil, GST, freight and installation included?
Who services the unit near my site?
Manufacturers of 400 kVA servo stabilizers design the unit, wind its transformers and variacs, and assemble and test it in their own factory. Suppliers, dealers and traders buy finished units and resell them. SG Power is both, so you deal with the maker directly, including for custom input ranges and designs.
| Manufacturer (such as SG Power) | Supplier, Dealer or Trader | |
|---|---|---|
| Design and transformers | Designs the unit and winds its transformers and variacs | Buys finished units |
| Custom input range or design | Built to your site | Limited to stock models |
| Testing | Routine-tests every unit in its own factory | Depends on the maker |
| After-sales support | Direct from the factory team | Passed back to the maker |
For more on choosing a maker, read about automatic servo voltage stabilizer manufacturers in India.
Buying a 400 kVA servo stabilizer from SG Power takes five steps, from sharing your load details to installation. Our team checks the size, recommends the input range and design, and sends a written quote. The unit is then built and tested in our Ghaziabad factory before dispatch.
Share your details: load list, single-line diagram if available, lowest and highest site voltage, room conditions and location.
Get sizing and a quote: we confirm whether 250, 400 or 500 kVA suits you, and which input range and design, and send a written quote.
Confirm the order: approve the specification, drawings and quote.
Manufacturing and testing: the unit is manufactured and tested in our Ghaziabad factory.
Dispatch and installation: the unit is sent to your site, with installation support on request.
Ready to start? Send your load list today.
Buyers choose SG Power among 400 kVA servo stabilizer manufacturers because it has built power products for 15+ years, winds its transformers in-house and tests every unit before dispatch. Its catalogue lists the 400 kVA oil cooled model, in balanced and unbalanced designs, with service in 127+ cities.
| Why SG Power | Detail |
|---|---|
| Experience | 15+ years of manufacturing electrical and power products |
| Factory | 7,000 sq m in Ghaziabad, 84 machines, 250+ employees |
| Quality checks | 100% of units tested; a 3-level quality check covering 173 checkpoints |
| Certifications | ISO 9001:2015 certified organisation; RoHS certificate covering servo stabilizers; MSME and SSI registered |
| Customers | 5,937+ customers in 319+ cities; after-sales service network in 127+ cities |
| Retention | 89% customer retention and 93% dealer retention, with 1,319 dealers |
| Full range | Air cooled 10–50 kVA and oil cooled up to 500 kVA, including the 250, 400 and 500 kVA oil cooled models |
| Other products | Transformers, earthing and lightning protection |
The servo stabilizer design has been tested at an NABL-accredited laboratory, and SG Power is an ISO 9001:2015 certified organisation. See the full range on our servo voltage stabilizer page, compare air cooled, oil cooled and 3 phase stabilizer models, or learn more about SG Power.
SG Power's servo stabilizers, earthing, lightning protection and other electrical products are supplied to government bodies, PSUs and well-known companies across India. These buyers include power utilities, metro and railway projects, defence units and large manufacturers. The organisations below appear with purchase orders in SG Power's catalogue:
| Sector | Organisations |
|---|---|
| Power and utilities | POWERGRID, NTPC, BHEL, NPCL, Adani, Reliance Power |
| Infrastructure and metro | L&T, Alstom, Indian Railways, Tata (smart city project), Welspun |
| Defence and government | DRDO, Indian Army, Indian Air Force, BSF, Ministry of Defence, Airports Authority of India |
| Industry, telecom and corporate | Hindalco, JK Cement, Jubilant, Bhushan Power, BSNL |
Project Location - Karnataka
Power infrastructure project with advanced electrical solutions.
Project Location - Kanheri Hills
Defence sector electrical and protection systems.
Project Location - Hyderabad
Airport infrastructure and electrical safety solutions.
Project Location - Pune
Metro rail electrical installations and grounding systems.
Project Location - Ajmer
State electricity distribution network solutions.
Project Location - Jodhpur
Power distribution and earthing solutions.
Project Location - Bangalore, Noida
Heavy electrical and industrial power systems.
Project Location - Odisha
Steel industry electrical infrastructure solutions.
Project Location - Nashik, Chhattisgarh
Defence-grade electrical protection systems.
Project Location - Lucknow, Jabalpur
Telecom infrastructure and grounding systems.
Project Location - Ghaziabad
Government electronics and power systems.
Project Location - Sambalpur
Aluminium industry electrical safety solutions.
Project Location - Srinagar
Military-grade electrical infrastructure.
Project Location - Kerala
Railway electrification and protection systems.
Project Location - Rajasthan
Cement industry electrical solutions.
Project Location - Haryana
State power distribution infrastructure.
Project Location - Noida
Industrial electrical and safety systems.
Project Location - Khavda, Bikaner
Large-scale construction and power projects.
Project Location - Noida
Private electricity distribution systems.
Project Location - Chhattisgarh
Thermal power plant electrical solutions.
Project Location - Shahjahanpur
Power generation and infrastructure systems.
Project Location - Gurugram
Aviation electrical infrastructure solutions.
Project Location - Noida
Smart city electrical and infrastructure systems.
SG Power Products Pvt. Ltd. is rated 4.2 out of 5 from 133 buyer ratings on IndiaMART (checked 4 November 2026). Its Noida office is rated 4.4 out of 5 from 78 Google reviews (checked October 2026). On IndiaMART, 83% of buyers report overall satisfaction, and SG Power scores 86% for response.
| Source | Rating or Score | Based On |
|---|---|---|
| IndiaMART | 4.2 out of 5 | 133 buyer ratings |
| IndiaMART user satisfaction | 83% | IndiaMART buyer feedback |
| IndiaMART response score | 86% | IndiaMART buyer feedback |
| Google (Noida office) | 4.4 out of 5 | 78 reviews |
Buyers comparing 400 kVA servo stabilizer manufacturers can check these ratings independently.
The ratings cover all SG Power products, not 400 kVA servo stabilizers alone. Recent IndiaMART reviews come from buyers of three-phase servo controlled voltage stabilizers, earthing electrodes, lightning arresters, trefoil clamps and rectifiers.
Before ordering a 400 kVA unit, you can also ask any maker for references from similar installations, a routine test report and a visit to its factory.
Read SG Power reviews on IndiaMARTSG Power Products Pvt. Ltd. is among the 400 kVA servo stabilizer manufacturers and suppliers in Sector 62, Noida, with its own factory in Ghaziabad. It supplies and services 400 kVA units across Delhi NCR, Uttar Pradesh and the rest of India. Buyers in Delhi, Noida and Gurugram get local sizing and service.
Looking for 400 kVA servo stabilizer suppliers in Delhi NCR, a 400 kVA servo stabilizer in Noida or 400 kVA servo stabilizer manufacturers near me? Our Sector 62 office and Ghaziabad factory serve the whole NCR, including Greater Noida, Sahibabad, Okhla, Faridabad and Gurugram. We also supply customers in 319+ cities, including Noida, Delhi, Gurugram, Ghaziabad, Lucknow, Jaipur, Ahmedabad, Mumbai, Pune, Hyderabad, Bengaluru and Chennai.
What buyers in Delhi NCR get from SG Power:
Sizing and quotes from our Sector 62, Noida office
Manufacturing and testing at our own Ghaziabad factory
After-sales service through a network in 127+ cities
SG Power Products Pvt. Ltd.
17th Floor, L-17-1714B, The Iconic Corenthum, Plot No. A-41, Sector 62, Noida, Gautam Buddha Nagar, Uttar Pradesh 201309
Phone: +91-8929722150 · Email: enquiry@sgpower.co.in · Contact page
Want a 400 kVA industrial servo stabilizer delivered to your site? Ask for a quote, and we'll confirm the model and price.
These are the main facts about SG Power's 400 kVA servo voltage stabilizer, in short form for quick reference:
What it is: a three-phase, oil cooled servo voltage stabilizer rated 400 kVA, listed in SG Power’s catalogue.
Load: about 320 kW at full rating; keep the running load to about 256 kW.
Current: about 556 A per phase at 415V.
Cooling: oil cooled (ONAN), for continuous duty and hot or dusty rooms.
Output: 410V ±1% phase to phase, 230V ±1% phase to neutral, 97% efficiency tested to IS 2026 (Part 1), 100% load continuously.
Input: 170–280V per phase, or 340–480V phase to phase; custom ranges on request.
Fits: running loads of about 160 to 256 kW; above that, choose 500 kVA.
Price: on request, after a free load check.
Ratings: 4.2 out of 5 from 133 buyer ratings on IndiaMART, and 4.4 out of 5 from 78 Google reviews.
Maker and supplier: SG Power Products Pvt. Ltd., Noida, one of the 400 kVA servo stabilizer manufacturers and suppliers in India, with its own factory in Ghaziabad.
* Prices are indicative. For the latest price, contact SG Power.
* Prices are indicative. For the latest price, contact SG Power.
For the latest factory price, contact SG Power, direct 400 kVA servo stabilizer suppliers, with your load list, single-line diagram, room conditions and lowest site voltage. We’ll confirm whether 250, 400 or 500 kVA and which input range suit your plant, build the unit for your site and support it after installation.
The specifications on this page come from SG Power's product catalogue (February 2026), its KNEUTRON servo stabilizer catalogue and its 400 kVA oil cooled datasheet, checked in November 2026. Load and current figures are calculated at 415V and a 0.8 power factor. Final values are confirmed in our quotation.
SG Power Products Pvt. Ltd., product catalogue (February 2026): range, oil cooled models, features, transformers, quality checks, certifications and clients
SG Power KNEUTRON servo stabilizer catalogue: input bands, output voltage, regulation, efficiency, output delay and protections
Indian user forums (checked November 2026): TechEnclave, HiFiVision and Team-BHP threads on large three-phase servo stabilizers
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