High frequency current detection
Current sense transformers are used to detect high frequency currents, in order to protect an electronic switch against overcurrents in switching converters. They are typically connected at the primary side of medium-high power high frequency transformers, but they are furthermore suitable for currents measurement, in applications which don’t require high accuracy, but prompt response of the measurement equipment instead.
Features
From a building point of view, high frequency current transformers can be wound either on toroidal cores or on E cores. Toroidal models are available with passing-through hole, but some of them are feasible with the inserted primary turn too.
Linear models, based on E cores, are available exclusively with the primary turn inside, so they are especially recommended for control functions in equipments where the low cost is achieved by simply, strong and easy-mounting components. All standard current sense transformers are made according the safety standard IEC 742 for working voltage up to 600 Vrms, with patended bobbins that were developed by Sirio.
- Typical working temperature is from -25 to +85°C.
- The plastic material of the case is UL94-HB or UL94-V0 on request.
Main features of current sense transformers
- n: secondary to primary turns ratio, that is the number of secondary turns
- RS: secondary winding’s resistance
- Ip: rated primary current (rms value)
- LS: rated secondary inductance
- fn: optimum working frequency (or optimum working frequency range)
- Vt: minimum secondary transfer area at 25°C
- Uis: maximum working voltage primary/secondary
- Up: isolation voltage primary/secondary
- D: central hole diameter/primary turn diameter
