RELAYS
IDMT O/C & E/F Relay - ACDG

This relay is used to give time graded protection of electrical installations and simple line systems, such as feeder system, transformer, AC machines etc. against short circuit or against ground faults of solidly earthed system. This relay may be used as principal relay or as back-up relay.

Description / Specifications
The relay consists of an electromagnetic element driving an aluminium induction disc. The damping is provided by a permanent magnet mounted on Jewel Bearings.

Settings
Phase Fault : 50-200% in equal tap setting.
Earth Fault : 20-80% or 10-40% in 7 equal tap setting of 5A or 1A
Starting & Closing: 100%-130% of current setting as per ISS

Thermal Rating
2 x rated current continuously or 20 setting current for 3 seconds.

Burden
3VA at highest tap and 2VA at lowest tap.

Contacts
2 N/O self reset plus 1 N/O or 1 N/C S/R or H/R contacts.

Auxiliary Unit Rating
Shunt connected 30, 50, 110, 220V DC or 110V

Operation Indicator
Hand reset type on Auxiliary Unit.

Case
ACGD11 – 170W x 235H x 175D mm (150 x 220mm cutout)
ACDG31 – 475w X 265H x 176D mm (435 x 222mm cutout)

The relay conforms to IS 3231 - 1965