Resitech Electricals

The epoxy resin castings that we offer are ideally engineered for high voltage applications. These epoxy resin castings are specially designed for use in heavy duty application such as high voltage electrical industry where high short circuit currents and dynamic forces are expected. We also fabricate these epoxy resin castings into complicated shapes as per customer’s specifications thus, reduce sub assembly work. Some of its advantages are listed underneath :

• The epoxy resin casting offers excellent dielectric strength in all directions.


• It has good resistance to moisture.


• It offers excellent adhesion to metal.


• It has outstanding anti tracking properties.


• It has excellent dimensional stability.


• It offers high thermal conductivity.

The diverse areas of application are listed below :

• Molded insulators.


• Terminal blocks and boards.


• Busbar supports.


• Seal off Bushing.


• Epoxy bushings.


• Molded housings.


• Distance pieces.


• Interface barriers.


• Post insulators.


• Shrouds etc, etc

It is not advisable to use the line current directly for measurement and relaying purpose as it can pose high value and insulation problem. To answer this problem we manufacture low tension current transformers. These low tension current transformers are made up of a piece of electrical equipment that converts line current values that are suitable for the measuring instruments, meters, protection relays. Some of the common categories of low tension current transformers are as follows :

• Ring type Cts : This type has an opening in the center to accommodate primary conductor (busbar or cable) through it.


• Bar primary Cts : These have a primary winding that consists of bar of suitable size and material that forms an integral part of the CT.


• Wound types Cts : This type of CT has primary winding of more than one full turn wound on the core.


• Interposing CTs : These are mainly used in conjunction with main CTs to change the ratio of main CT or to provide isolation to meters or relays from main CTs secondary circuit. Primary current of these CTs is generally lower than 10 amp. This is the reason why they are always wound in primary types.


• Summation Cts : In special cases when current flowing in more than one feeder is required to be metered, this type of transformers is used. They usually have one primary winding and one common secondary. The standard primary & secondary currents are 5 or 1 amp. We manufacture the Summation current transformers are manufactured in strict conformance to ISS 6949.


• Bushing type or bus duct Cts : This category has Ring type construction and can be easily mounted on Bus duct or Bushing turret of power transformer.

We manufacture high quality resin cast current transformers that are needed in many industries. These resin cast current transformers are basically dry type transformers whose body is completely embedded in quartz loaded epoxy resin making use of Vacuum molding technique. After molding is done, the resin is made hard using polymerization technique. This resin acts as the main insulation between primary and secondary and earth. This accounts for the technical advantages that resin cast current transformers have over the others. Their design details are mentioned below:
The basic designs come in three major types and these cover the entire range of 11KV Resin Cast and oil filed CTs for primary currents that range up to 2500A. We also offer 22 Kv Resin Cast CTs. Given below are the types of cast resin :

• The wound primary cast resin PR type for low ratios.


• The bar primary cast resin BR type for higher ratios.


• The window types cast resin WR type without primary for still higher ratios.

Mainly The PR type is a wound primary type CT that is specially designed to cover currents that start from 25 amps to 300 amps. The bar type BR CTs are designed with a bar as primary. These CTs cover a range of primary currents from 300 amps to 1000 amps. All the higher ratings of primary Currents are covered by the WR type of Window CTs. The numerous advantages of the resin cast CTs are listed below :

• These serve the purpose of insulation.


• They have a Compact design for high mechanical and dielectric properties.


• They eliminate chances of fire spread and therefore there are no chances of permanent damage to the equipment.


• Epoxy is non hygroscopic and gives very good insulation properties even in humid conditions.


• It does not age or wear out easily.


• It has excellent toughness. Even The molding has a non wearable glossy surface this make the CT requires maintenance free.

We manufacture highly efficient and accurate resin cast potential transformers. These resin cast potential transformers are used In AC circuits, for the purpose of measuring large voltages. Their main function is to reduce the supply Voltage to a small value so that it can be easily measured with standard low range AC instruments of moderate size and capacity. There are many advantages of using resin cast potential transformers for range extension of AC meters. We also offer resin cast potential transformers of dual purpose Metering & Protection that are also commonly used. These resin cast potential transformers have some special features which are :

• These come with an additional secondary winding that is connected in open delta so that if these is an earth fault on any of the phases, required voltage is developed across the open delta terminals which is then used to actuate a tripping mechanism.


• The instrument is mostly isolated from line voltages. Thus, it can be grounded.


• It is possible to achieve standardization of instruments and meters at secondary ratings of 110V.


• Several instruments can be connected from a single transformer.


• The power connected in measuring circuits is low.

Thus, the Resin Cast Potential Transformers are basically dry type transformers, whose active part is completely embedded in quartz loaded Epoxy Resin by using vacuum molding technique. The resin is hardened by polymerization after molding.
The main insulation between Primary and Secondary & Earth is obtained by this epoxy resin. Their special features are :

• Compact design


• High mechanical properties


• Excellent electrical properties


• Non hygroscopic


• Good insulation properties

The various other types of resin cast potential transformers that we offer are as follows :

• Single phase resin cast PT with fuse: VT2


• Two faze resin cast PT: VT4


• Single phase resin cast PT with fuse: VT5