Toroidal Transformers - CT1/CTD1 - Fanox

Earth Leakage Protection & Measurement Transformers for Low Voltage.

To be used with ELR-B, ELR-3C, D30 and DM30 relays.
The transformer and relay assembly sensitivity is fixed by the relay.
The toroidal transformer CTD-1/28 is specifically designed for DIN rail mounting.

Tipe	Code	Core	Inner ø	Weight(kg.)
CTD – 1/28	41055	–	28 mm	0,2
CT-1 / 35	41060	Closed	35mm	0,2
CT-1 / 60	41065	Closed	60mm	0,3
CT-1 / 80	41070	Closed	80mm	0,5
CT-1 / 110	41075	Closed	110mm	0,5
CT-1 / 160	41080	Closed	160mm	1,4
CT-1 / 210	41085	Closed	210mm	1,5
CT-1 / 300	41088	Closed	300mm	4,4
CT-1 / 350	41090	Closed	350mm	4,8
CT-1 / 400	41092	Closed	270mm	8,3
CTA-1 / 60	41066	Open	60 mm	0,3
CTA-1 / 110	41076	Open	110mm	0,5
CTA-1 / 160	41081	Open	160mm	1,4
CTA-1 / 210	41086	Open	210mm	1,5

Working principles: The toroidal transformer is installed between the source and the load. The system works on the current balance principle. In a correct installation the vector sum of the currents is zero and the relay will not trip.

In case of an insulation fault on the circuit a leakage current flows to earth. Now the vector sum of the current passing through the transformer is not zero, this imbalance is detected by the transformer, which induces a current in the secondary winding which is connected to the relay.

If the fault level is higher than the selected sensitivity, and when the trip time delay has elapsed, the relay trips and actuates on the shunt trip of a circuit breaker or the coil of a contactor interrupting the supply to the load.

The dimensioning of the toroidal transformer depends on the diameter of all active wires (not earth conductors) put through the transformers.