UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Current transformer termination best practice

Ed_Dinning · 8th Apr 2021, 8:57 pm

Hi Al, in power system practice it is nor unknown for a CT sec to become disconnected on a metering application. The usual trick was to fit a voltage dependent resistor (varistor, etc across the terminals and heatsink this device. Quite a bit of power can be dissipated in this device and it was normal to fit a latching thermal switch onto the heatsink with spare contact to operate an alarm.
Note that a zener will not work well in this position

Ed

8th Apr 2021, 8:57 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Current transformer termination best practice - a theoretical situation Hi Al, in power system practice it is nor unknown for a CT sec to become disconnected on a metering application. The usual trick was to fit a voltage dependent resistor (varistor, etc across the terminals and heatsink this device. Quite a bit of power can be dissipated in this device and it was normal to fit a latching thermal switch onto the heatsink with spare contact to operate an alarm. Note that a zener will not work well in this position Ed