Current Transformers

Current transformers are basically used as it is not possible to use line current directly for measurement and relaying purpose due to its high value and insulation problem. CURRENT TRANSFORMER which is widely known as 'CT' is a piece of electrical equipment which converts line current ( primary current ) in to small standard current values which are suitable for the devices to which it is connected e.g. measuring instruments, meters, protection relays.
Yokins manufactures metering, protection Class LT CTs in tape wound and resin cast constructions as required. CTs are available from 5A to 4000A with an accuracy of 0.5% & 1% as per  IS 2705. Standard secondary current is 1A & 5A.Toroidal (round) and rectangular CTs are manufactured to suit various busbar sizes.

• -    Basic Functions for Current Transformers
• -    To reduce line current to a value which is suitable for standard measuring instruments, relays etc.
• -    To isolate the measuring instruments, meters, relays etc. from line voltage of an installation.
• -    To protect measuring instruments against short circuit currents.
• -    To sense abnormalities in current and give current signals to protective relays to isolate the defective system