Torotrans Katraj, Pune, Maharashtra

A toroidal transformer has ring type core made from cold rolled grain oriented ( CRGO ) Silicon steel strip without any joints and annealed for stress relief after being wound. These wound cores are then suitably insulated by class B insulation and the winding of copper wire is usually done by winding machines.The core being continuous, without any air gap and the path of flux being along the direction of grain orientation, gives an opportunity for optimum use of flux density, besides very low iron loss and exciting current. The primary and secondary windings are closely linked magnetically. Therefore the leakage fluxes and reactance are negligible. A toroidal transformer has its winding spread over the entire periphery of the core. This results in largcr area for dissipating the heat. Till recently all such small low voltage type transformers needs were met almost universally by traditional or conventional El transformers. Now materials are easily available, so it has been possible to develop 'LOW VOLTAGE TOROIDAL TRANSFORMER' giving a whole set of advantages and wide range of applications in place of conventional transformers.

Current transformers are used for electrical measuring instruments and / or electrical protective devices. They are very useful in high power circuits where the current is large. Current transformers are subdivided into two main categories. MEASURING CURRENT TRANSFORMERS These transformers are used in measuring and indicating current, that is to reduce the line current to a value which is suitable for standard measuring instruments, relays etc.     PROTECTIVE CURRENT TRANSFORMERS These transformers are used for over current and undercurrent relaying for power circuit protection   TYPE : Current Transformers are normally categorized as Ring / Bar type and Wound Primary Ring / Bar type current transformer : A current transformer where primary winding is provided by 'the user. Wound primary current transformer : A current transformer having a primary winding of more than one full turn wound on core. Current Transformers are wound on Toroidal cores which virtually eliminates error due to leakage flux. Adjusting the number of secondary turns may compensate for some errors. Electrical Specifications : Type : Tape insulated Ring type and Epoxy Resin Potting type Primary Current : 50 Amp. To 3000 Amp. in ring type. 25 Amp. To 600 Amp. in epoxy resin Secondary Current : 5 Amp. and 1 Amp. for ring type. 0.2 , 0.1 and 0.05 Amp. for epoxy resin (other on request) Burden : 5, 10, 15 VA. for ring type. 0.25, 0.5, 1 and 2 VA. for epoxy resin type (other on request) Accuracy Class : 0.2, 0.5, 1.0, 5.0, 10.0 Frequency : 50 Hz Operating Temp. : - 10 deg. C to 40 deg. C. Conforms to : IS 2705