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Leipole Electric

Three-phase control transformer

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Overview

Three-phase transformers for high-power applications with optimized heat dissipation.

  • Three-phase power conversion: three-phase input and output for industrial and high-power equipment.
  • High-power application: designed for heavy equipment.
  • Heat dissipation design: efficient structure for long-term working stability.

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Key advantages

  • Amorphous Core Option for Ultra-Low No-Load Losses
    Utilizing amorphous metal laminations cuts no-load losses by up to 70% versus standard CRGO steel, delivering unmatched energy savings in lightly loaded applications.

  • Optimized Short-Circuit Impedance Profiling
    Custom-engineered winding spacing and turns ratio produce precise %Z values, ensuring controlled fault currents for selective coordination without excessive voltage drop under full load.

  • Impulse Voltage Withstand Class III
    Class-III impulse insulation systems (up to 250 kV peak) protect downstream electronics from transient surges—critical in lightning-prone or utility-unstable grids.

  • Low-Audible-Signature Acoustic Design
    Acoustic dampening laminations and “split-winding” coil construction reduce magnetostriction noise to below 35 dB(A)—essential for installations in noise-sensitive environments.

  • Phase-Shift Vector Engineering
    Availability of uncommon vector groups (e.g., Y-Yn0, D-Yb1) enables substation designs that eliminate circulating currents in parallel transformer banks and optimize grounding schemes.

  • Thermal Hot-Spot Monitoring
    Embedded fiber-optic temperature sensors directly contact the hottest coil turn, giving real-time hotspot data far more accurate than standard external RTDs.

  • Bi-Directional Tap-Changer Automation
    Microprocessor-controlled on-load tap changers automatically adjust both raise and lower taps to maintain voltage within ±0.5% under dynamic load swings.

  • Nanocomposite Varnish Insulation
    Advanced nanocomposite resin coatings provide superior adhesion, dielectric strength, and moisture resistance—extending coil life in high-humidity or chemical-exposure zones.

  • Harmonic Mitigation Winding Algorithms
    Proprietary winding interleaving patterns attenuate 5th and 7th order harmonics, reducing harmonic heating and improving power quality for VFD-dominated loads.

  • Eco-Friendly Ester-Filled Designs
    Synthetic ester dielectric fluids offer a 50% higher flash point than mineral oil, biodegradable properties, and better dielectric recovery—ideal for environmentally sensitive sites.

Models & specifications

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model Capacity KVA bl max b2 max dl d2 hl MAX LI MAX nl n2
2 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-0.16 016 64 50 5x8 M4 140 122 49 90
3 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-0.25 025 67 48 6x12 M5 162 156 49 113
4 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-0.4 04 82 56 6x12 M5 162 156 64 113
5 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-0.63 063 76 51 7.4x13 M6 187 181 56 136
6 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-1 1 97 61 7.4x13 M6 187 181 76 136
7 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-1.6 16 115 98 7.4x13 M6 214 229 94 170
8 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-2.5 25 133 102 10x18 M8 241 264 101 200
9 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-4 4 148 104 10x18 M8 250 270 118 224
10 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-6.3 63 155 129 10x18 M8 320 360 127 264
11 Kiva 09/07/2025 07:45 AM Kiva 09/07/2025 07:45 AM JSG-8 8 170 134 12x20 M10 380 420 140 315
Model Capacity KVA bl max b2 max dl d2 hl MAX LI MAX nl n2

SG electric transformer

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at odel Capacity KVA L B H
1 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-2.5 25 300 240 280
2 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-3 3 300 240 280
3 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-4 4 390 280 320
4 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-5 5 390 280 320
5 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-6 6 390 280 320
6 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-8 8 500 350 450
7 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-10 10 500 350 450
8 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-12 12 500 350 450
9 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-15 15 500 350 450
10 Kiva 09/07/2025 08:03 AM Kiva 09/07/2025 08:03 AM SG-20 20 600 420 520
odel Capacity KVA L B H
3 phase transformers SGB
wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model L (mm) W (mm) H (mm) A (mm) B (mm) KF F
1 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-0.5KVA 180 110 187 136 78 75,00 2
2 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-1KVA 180 130 187 136 98 75,00 2
3 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-1.6KVA 240 180 240 200 114 10,00 4
4 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-2KVA 240 190 240 200 124 10,00 4
5 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-2.5KVA 300 170 290 224 104 10,00 4
6 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-3KVA 300 190 290 224 124 10,00 4
7 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-4KVA 300 200 290 224 134 10,00 4
8 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-5KVA 300 220 290 224 154 10,00 4
9 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-6KVA 300 240 290 224 174 10,00 4
10 Kiva 09/07/2025 08:04 AM Kiva 09/07/2025 08:04 AM SGB-7KVA 360 200 350 264 125 14,00 4
Model L (mm) W (mm) H (mm) A (mm) B (mm) KF F

Applications

  • Industrial Power Distribution – Step down medium-voltage utility power to low-voltage levels for plant-wide equipment operation.

  • Manufacturing Machinery Supply – Provide stable 3-phase voltage to CNC machines, conveyor systems, and production lines.

  • Data Centers – Feed critical IT loads with balanced, clean power to support uninterrupted server operations.

  • Renewable Energy Integration – Convert generator output from wind or solar farms to grid-compatible voltage.

  • Mining and Heavy Industry – Power large motors, crushers, and drilling rigs in remote or rugged environments.

  • HVAC and Chiller Systems – Supply high starting-current motors for large commercial air conditioning and refrigeration units.

  • Marine and Offshore Platforms – Deliver reliable 3-phase power to ship propulsion, pumps, and navigation systems.

  • Hospitals and Critical Facilities – Maintain regulated voltage for sensitive medical equipment and emergency systems.

  • Transportation Infrastructure – Power railway traction systems, maintenance depots, and signaling equipment.

  • UPS and Backup Power Systems – Interface between generators and UPS units for stable emergency power.

Basic knowledge

1. Core Materials & Lamination Quality

  • Grain-oriented silicon steel: Premium laminations reduce hysteresis losses by up to 50% compared to generic CRGO steel. Insist on ≤0.23 mm lamination thickness for continuous-duty applications.

  • Inter-laminar insulation: Many budget units skimp here—voids or resin-poor layers lead to eddy-current hotspots and accelerated insulation aging.

2. Cooling & Thermal Management

  • Directed airflow ducts: High-power transformers should include built-in air channels that direct cool air over the hottest core tones, not just free-convection fins.

  • Oil-free vs. oil-filled: Dry-type designs avoid fire risk and leak concerns, but require precise ambient temperature control. Oil-filled units can tolerate higher loads if you monitor oil temperature with RTD probes.

3. Vector Group & Phasing Impacts

  • Phasor alignment: Incorrect vector group (e.g., Δ–Y vs. Y–Y) can introduce phase shifts that conflict with upstream protection relays, causing nuisance trips. Always match the upstream feeder’s vector designation.

  • Zero-sequence paths: In Y–Δ transformers, the Δ winding handles unbalanced load currents; omitting it causes neutral overvoltages under single-phase loads.

4. Harmonics & Nonlinear Load Handling

  • K-factor ratings: When feeding VFDs or UPS systems, specify a transformer with K-factor ≥ 13 to withstand harmonic heating. Standard units overheat prematurely under diode-rectifier loads.

  • Shielded windings: Electrostatic shields between primary and secondary reduce the transfer of high-frequency noise into sensitive downstream equipment.

5. Installation & Vibration Control

  • Anti-vibration mounts: In factories with heavy machinery, spring or rubber-isolated feet prevent core-coil loosening. Rigid mounting can lead to clacking noises and winding fatigue under resonant frequencies.

  • Orientation matters: Position the transformer so its breather and any pressure-relief valves are accessible—burying them makes routine oil maintenance and safety checks hazardous.

6. Environmental Protection & Site Preparation

  • NEMA/IEC enclosures: For outdoor or wash-down areas, choose NEMA 3R or IP 23 enclosures. Internal drip shields and raised cable entry glands keep moisture off windings.

  • Corrosive atmospheres: In chemical plants, PTFE-coated tank interiors and stainless-steel fasteners prevent acid-induced metal corrosion that can disable grounding lugs.

7. Condition Monitoring & Predictive Maintenance

  • Partial discharge testing: Annual PD scans catch insulation voids before they evolve into catastrophic failures—most facilities skip this until it’s too late.

  • Infrared thermography: Spot-check winding end-terminals and bushing connections under full load. A 5 °C hotspot can halve coil lifetime if left unchecked.

8. Lifecycle & Upgrade Strategies

  • Plug-in tap changers: On-load tap changers allow voltage regulation without shutdowns—ideal for critical processes. Budget units often omit this feature, forcing downtime for manual adjustments.

  • Transformer retrofits: Replacing core laminations and rewinding coils with halogen-free, high-temperature Class H insulation can extend life by 10–15 years rather than full replacement.

Frequently asked questions

When should you specify a 3-phase dry-type transformer with K-factor rating?

For environments powering variable-frequency drives, choose a 3-phase dry-type transformer K-factor rated (e.g., K-13 or higher). It handles harmonic currents without overheating and doesn’t require oil containment.

How do you select a 3-phase pad-mounted transformer for outdoor use?

Pick a 3-phase pad-mounted transformer outdoor rated enclosure (NEMA 3R/IP23) with anti-condensation breathers. Ensure corrosion-resistant finish and fuse compartments for safe urban or rural installations.

What are the benefits of an on-load tap-changer 3-phase transformer?

An on-load tap-changer 3-phase transformer lets you adjust secondary voltage under load to maintain stable output during supply fluctuations—critical for data centers and continuous-process plants.

Why choose a 3-phase oil-filled transformer for high-capacity power distribution?

A 3-phase oil-filled transformer high-capacity uses mineral or ester oil to cool and insulate, supporting higher kVA ratings in a compact footprint while offering longer thermal life than dry types.

How do you size a 3-phase transformer for UPS and generator paralleling?

For UPS-generator systems, use a 3-phase transformer for UPS paralleling sized at 125% of continuous load, with delta–wye vector matching the upstream sources to prevent circulating currents and ensure proper syncing.

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Selection & support

Selecting a LEIPOLE three-phase transformer

Match the rating, voltages and application to the three-phase supply.

Which three-phase transformers does LEIPOLE supply?

LEIPOLE supplies three dry-type series: SG low-voltage transformers from 2 to 100 kVA, SGB transformers from 0.5 to 50 kVA, and JSG servo transformers from 0.16 to 10 kVA, which adapt the supply voltage to servo drives and machine tools. The model tables give the mounting dimensions of each rating.

Compare single-phase transformers

When do I need a three-phase rather than a single-phase transformer?

Use a three-phase transformer when the load itself is three-phase, such as servo drives, motors or a whole machine, or to change the voltage of a three-phase supply; use a single-phase control transformer for the control circuit of contactors, relays and lamps. Send the primary and secondary voltages, kVA rating and quantity for a quotation.

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