TARD0 pages

TARD

Current Transformers
Accessories for the RD family

DESCRIPTION
Toroidal Transformers (TARD) can be
combined with the RD family of Earth Leakage
Relays to detect current leakages due to loss of
ground insulation. The TARD fits on the live
wires of the single, two or three phase supply
(phases and neutral if distributed), while the
safety wire should not be included.
A signal proportional to the vectorial sum of the
active current (L1+L2+L3 in case of a three
phase line with neutral) is sent to the differential
relay. The coil is insulated from the magnetic
core and undergoes an insulation test of 2,5 KV
at mains frequency for one minute. The TARD
are made in highly permeable magnetic
materials and are available with internal
diameters from 35 mm to 210 mm in closed or
open format, allowing the fitting on bars and
cables up to considerable dimensions. The
enclosure is made with insulating and fire
retardant covers, provided with fins for
mechanical fitting and accessories for the fixing
on DIN guides.
The connection between the RD and the TARD
should be made with shielded cables. This kind
of consideration should be taken when the
currents to be registered are under 100mA.

The cables should be twisted in case no
shielded cables are used.
The distance of the connection should be as
short as possible and additionally far away from
power cables and other devices that may cause
electromagnetic interference.

SPECIFICATIONS
Nominal Frequency: 47 to 63 Hz
Ratio of measure winding: 500/1
Insulation test: 2,5 kV 50/60 Hz (60 sec.)
Permanent Overload: 1000 A
Thermal Overload: 40 kA (1 sec.)
Working temperature: -10° to 55°
Terminals: Screws for 16 AWG 1.6 mm²
Covers material: fire retardant plastic

Example of connection with the RD-1 model

Quality Certified ISO 9001:2000

Protection Relay
TARD_GBBR_220905