1. What is a Transformer?
A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It converts voltage levels while maintaining the same frequency, enabling efficient long-distance power transmission and distribution.
2. Transformer Types
- Dry-Type Transformer: Uses air cooling, fire-resistant, safe for indoor use. Common models: SCB10, SCB11, SCB12, SCB13.
- Oil-Immersed Transformer: Uses mineral oil for cooling, high efficiency for outdoor use. Common models: S11, S13, S22.
- Instrument Transformer: Current transformers (CT) and potential transformers (PT) for measurement and protection.
3. kVA Sizing Guide
- Standard range: 30kVA – 3150kVA for dry-type; up to 10MVA for oil-immersed.
- Formula: kVA = (V × I × √3) ÷ 1000 (3-phase)
- Rule of thumb: Size at 80% load for optimal efficiency; add 20% for future expansion.
4. Cooling Methods
- AN (Air Natural): Natural air circulation — standard for dry-type.
- AF (Air Forced): Fans for forced air cooling — higher capacity.
- ONAN (Oil Natural Air Natural): Oil circulation with natural air — standard for oil-type.
5. IEC Standards
Ziyao transformers comply with IEC 60076 series (Power Transformers), IEC 62271 (Switchgear), and IEC 61439 (Low-voltage Switchgear). Certification: ISO 9001, ISO 14001.