AltraVolt – Servo Voltage Stabilizer & Isolation Transformer Manufacturer

Technical Specifications

Capacity Range

10 kVA to 3000+ kVA (three-phase)

Input Voltage Range

300–480 V AC (configurable per site survey)

Output Voltage

380/400/415 V AC ± 1% (adjustable)

Type

Balanced (common control) or Unbalanced (independent phase control)

Response Time

< 20 ms; correction rate ~30–50 V/sec (servo driven)

Cooling

Air-cooled (up to ~100 kVA) or Oil-cooled (higher kVA, better overload handling)

Efficiency

> 97–98.5%

Overload Capacity

125–150% for short duration (model dependent)

Control

Microcontroller / digital PID-based servo control with LCD/LED display

Protections

Phase failure, reverse phase, overload, short circuit, surge, thermal

Mounting

Floor-mounted, optional wheels for portable units

Reference Standards

IS 9815 (servo stabilizer), IS 2026 Parts 1/2/3/5/8 (transformer design), IS 335 (oil), IEC 60076 (export-grade oil-cooled units)

Balanced vs Unbalanced Control

Balanced Type

All three phases are corrected together by one servo motor — economical and suited to loads with a fairly even/balanced supply across phases.

Unbalanced Type

Each phase has its own independent servo motor and control loop — essential where incoming supply or loading varies significantly between phases (common on rural/industrial feeders in India).

Indian Standards (BIS) for Three-Phase Stabilizers

Industrial-grade three-phase servo stabilizers draw on the same family of BIS specifications as single-phase units, with added emphasis on short-circuit withstand, oil quality, and insulation clearances given their higher kVA ratings.

IS 9815 (Parts 1 & 2) — Servo-Motor Operated Line Voltage Correctors

Part 1 sets general construction and terminology requirements; Part 2 sets the performance benchmarks — regulation accuracy, response time, losses, temperature rise, and routine/type test procedures. For three-phase units this extends to verifying performance under both balanced and unbalanced load and supply conditions, since industrial supply in India frequently has phase imbalance.

IS 2026 (Part 1) — General Requirements for Power Transformers

Defines rated voltage, rated power, terminology, tapping arrangements, and general design rules for the buck-boost transformer core inside the stabilizer — the same backbone standard used for full-size distribution and power transformers.

IS 2026 (Part 2) — Temperature Rise

Sets ambient temperature assumptions (normal limits of −25°C to +40°C for oil-immersed units) and permissible temperature rise of windings and oil under continuous full-load operation — critical for Indian summer conditions where ambient can regularly exceed 40°C, which is why site-specific deratings are often applied for stabilizers installed in hot regions.

IS 2026 (Part 3) — Insulation Levels, Dielectric Tests & Clearances

Specifies dielectric (high-voltage withstand) test levels and minimum clearances in air between live parts — directly relevant to the safety rating engineers ask for on industrial-grade three-phase units.

IS 2026 (Part 5) — Ability to Withstand Short Circuit

Specifies how the transformer winding inside the stabilizer must survive thermal and dynamic stresses from external short circuits (line-to-line, double-earth, and line-to-earth faults) without damage — important for stabilizers feeding CNC and motor loads where fault currents can be significant.

IS 335 — Insulating Oil

Oil-cooled three-phase stabilizers (typical above ~63–100 kVA) use EHV-grade mineral oil meeting IS 335 for dielectric strength, moisture content, and flash point — the same oil specification used across India's power transformer industry.

IEC 60076 — International Equivalent (for Export)

For three-phase stabilizers exported or supplied to multinational clients, IEC 60076 (the international power-transformer standard family) is often referenced alongside IS 2026, since the two are broadly aligned and many global buyers expect IEC terminology on datasheets.

Site survey first: Before specifying a three-phase servo stabilizer, it's standard practice to record actual incoming voltage swing (min/max per phase over at least 24–48 hours), connected load kVA, load type (motor/resistive/electronic), and required output tolerance — this is what determines correct kVA sizing, balanced vs unbalanced design, and air vs oil cooling.

Three-Phase Servo Voltage Stabilizer

Technical Specifications

Balanced vs Unbalanced Control

Balanced Type

Unbalanced Type

Three-Phase Servo Stabilizer KVA Range

50 KVA Three-Phase Servo Stabilizer

60 KVA Three-Phase Servo Stabilizer

75 KVA Three-Phase Servo Stabilizer

100 KVA Three-Phase Servo Stabilizer

125 KVA Three-Phase Servo Stabilizer

150 KVA Three-Phase Servo Stabilizer

200 KVA Three-Phase Servo Stabilizer