Borna - Air-Cooled Transformer Rectifiers
BORNA Electronic Company has manufactured and supplied cathodic protection TR panel types so as to protect cathodically the grids and pipelines with lesser length, small scale reservoirs, steel installations residential and office structures and concrete structures including bridges and also to prevent large amounts of expenses. Such transformer rectifiers are usually used within ranges of 10∼50 volts and 5∼30 amperes. However, air-cooled transformer rectifiers with higher ranges may be produced upon request.
This type of transformer rectifiers may be manufactured with different controls upon request (or according to cathodic protection design). Cooling system in such transformer rectifiers being of “AN” type. The degrees of protection of both oilcooled and air-cooled TR IP42 through IP55 will be upon request.
AC Input
- The input of the TR may be single or three phases in respect of its range of application. The input voltage in single-phase TKS being 50 Hz, 220/230 V and in three phase TKS being 50 Hz, 380/400V. A maximum output voltage by an input voltage 10% less than the nominal rate is obtained.
- Continuous input voltage 10% above nominal value will not damage the transformer or the rectifying elements or exceed component ratings.
DC Output
- BORNA transformer rectifiers are manufactured in different ranges 2∼250 volts and 5∼500 amperes upon request (or according to the cathodic protection design). TRs will be capable of supplying continuous full rated output at an ambient temperature of 50°C in shade at summer time and -20°C in winter
Transformer
- The following points have been considered in designing and manufacturing the transformer:
- Using iron transformer with a high magnetic field density in order to reduce the losses and to limit the increase of temperature in the transformer.
- Equipped to electrostatic shield between the primary and secondary coil.
- Insulation of transformer in sensitive points including in the proximity of the core is effected more strongly as they will be resistant against an increased temperature up to at least 130°C.
- All insulations dielectric test against an AC voltage of 2000V, 50 Hz for one minute.
- Minimum efficiency in different types of transformer is 95%.
- Borna transformer insulation classes may be as ordered by the client of A, B, E, F, H types.
- In oil-cooled TRs the transformer being wholly immersed in the oil and is designed in such a way that the temperature of various parts thereof in hot summer and in continuous full load does not exceed the degrees below:
- Maximum temperature of the coil being 50oC.
- Maximum temperature of the upper oil level being 45oC.
Rectifier
- Rectifiers are of silicon type structure. The circuit in a rectifier being of a full-wave bridge the efficiency of which being totally at least 90%. Rectifier components are protected against voltage impulse by a surge arrester and against current surge instantly by the fast (semiconductor) fuses.
- In oil-cooled transformer rectifiers, semi-conductors being wholly immersed in oil with a resistant coverage against corrosion. In auto-transformer type TRs, using of full wave Diode Bridge and in other types of transformer rectifiers, a full wave half controlled (semi-thyristor) bridge is used.