Elite Windings – Transformer FAQ
Clear, practical answers to common transformer questions — from how they work to sizing, maintenance, and reliability.
What is a transformer?
A transformer is an electrical device that transfers energy between two or more circuits using electromagnetic induction. It changes AC voltage levels without moving parts and is essential in power distribution, industrial systems, and commercial applications.
How does a transformer work?
AC in the primary winding creates a magnetic field in the core, which induces a voltage in the secondary winding. The output voltage is set by the turns ratio between the windings.
What are transformer windings made of?
Windings are typically aluminium or copper conductors insulated with materials such as kraft paper, polyester film, or Nomex to ensure dielectric strength and reliability.
What types of transformers are there?
Common types include power transformers, distribution transformers, isolation transformers, autotransformers, and instrument transformers for measurement and protection.
What is the difference between single-phase and three-phase transformers?
Single-phase transformers handle one AC waveform and suit residential or light commercial loads. Three-phase transformers handle three waveforms, offering higher capacity and efficiency for industrial and commercial systems.
What does kVA mean on a transformer?
kVA (kilovolt-amperes) measures apparent power, the product of voltage and current without power factor. Real usable power is Watts; kVA is equal to or greater than Watts depending on the load’s power factor.
What is transformer efficiency?
Efficiency is the ratio of output power to input power. Modern transformers often achieve 95–99% depending on size, core material, and winding design.
What is a tap changer?
A tap changer adjusts the turns ratio in steps to fine‑tune output voltage. Off‑load tap changers require de‑energising; on‑load versions adjust while in service for active voltage regulation.
What is transformer oil for?
Transformer oil insulates and cools internal components in oil‑filled units. It provides high dielectric strength, transfers heat, and protects windings from moisture and contaminants.
How long does a transformer last?
With correct installation, loading, and maintenance, transformers frequently last 25–40 years or more. Overloads, heat, and poor ventilation can shorten service life.
How do I know if my transformer is failing?
Warning signs include abnormal humming, overheating, oil leaks, voltage drops, tripped protection, or failed insulation resistance tests. These indicate the need for professional inspection.
Can transformers be repaired?
Yes. Repairs may include rewinding, insulation replacement, core repairs, bushing or lead replacement, and oil treatment. Scope depends on condition and economics.
Do you export transformers and windings internationally?
Yes. Elite Windings ships worldwide using Euro‑spec crates for protection in transit and does not add hidden export fees.
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