Rectifier Transformer Characteristics
Transformers for 12 pulse and 24 pulse rectifiers. Star/Delta, interconnected star (zigzag) and polygon connections. Close coupling between secondaries is normal, loose coupling is also available. Secondary terminations can be arranged to align with rectifier connections. Duty cycle derating is available.
The transformers can be supplied in enclosures to various degrees of protection, or open (un-enclosed) if preferred. Enclosure ratings of IP21 to IP33 are common and protection up to IP66 is also available for extreme conditions and flameproof applications. Enclosures are fitted with sealed marshalling boxes fitted with temperature and performance monitoring equipment. Enclosures can be fitted with interlocked doors to provide additional safety.
TMC cast resin transformers can be supplied with fans and controls to increase the rated capacity (kVA). Forced directed air circulation permits a continuous power increase of up to 35% above the rated capacity. Fans can be used to economically provide extra capacity for overload conditions such as cyclic load peaks and traction loads.
Information Required with Enquiry
- Rated power
- Voltages (at no-load)
- Voltage tapping range.
- Overload conditions
- Natural or fan cooling
- Number of phases
- Operating frequency
- Connection symbol (Vector group)
- Rectifier transformer connection type to AS1955.
- Ambient conditions
- Design standard
- Enclosure protection rating
- Temperature sensing equipment
- Current sensing equipment (CT’s).