3 Phase Transformers

Isolation transformers have separate primary and secondary windings, providing full electrical separation between input and output circuits. They can step voltage up, step it down, or keep it the same (for example, 415 V → 415 V) while reducing electrical noise and improving safety for connected equipment.

Autotransformers, by contrast, share a common winding and are typically used where isolation isn’t required. Offering a lighter, more compact, and cost-effective way to adjust voltage (such as 415 V → 220 V or vice versa).

We size based on connected load, inrush, ambient temperature, and future capacity. Share your total load requirements for a recommendation.

Unless specified, our transformers are designed for 100% duty cycle, meaning the transformer will operate 24/7 at the rated capacity, without the need of any cooldown periods.

Yes. We can design your transformers to your specifications, to include custom primaries/secondaries, and can include common ±2×2.5% taps for fine voltage adjustment.

• Input voltage: up to 3.3kV
• Output voltage: up to 3.3kV
• kVA rating: up to 750kVA
• Configuration: Dyn11 (standard) but designed to your needs
• Optional additions: electrostatic screens, multiple inputs/outputs, ±% off-load tappings, switchgear

All SES transformers are wound with high-conductivity enamelled copper, never aluminium. Copper delivers superior electrical performance, lower losses, higher mechanical strength, and better long-term reliability, especially under high load or harmonic conditions. While aluminium designs may reduce upfront cost, copper windings ensure maximum efficiency, durability, and thermal stability, essential for critical industrial and commercial applications where downtime isn’t an option.

SES Transformers are designed for 25+ years continuous operation, for when reliability, product life, and quality are priority.

Yes, we can fit electro-static screens between input & output windings of isolation transformers. These screens improve common‑mode noise attenuation for sensitive equipment.

Typical builds are Class F or H with temperature rise tailored to the environment.

Yes. Our standard transformers are built to K4 rating, suitable for most VFDs, rectifiers, and other moderate non-linear load applications where harmonic currents are present.

A K4-rated design allows for increased thermal capacity and reduced winding temperature rise under distorted load conditions. For more demanding systems, such as heavy harmonic or high K-factor environments, we can custom engineer transformers to any K-rating required, ensuring reliable performance, long service life, and compliance with your specific application.