Sel 421 - Page 47

U.1.5
Date Code 20090715 User’s Guide SEL-421 Relay
Introduction and Specifications
Models and Options
Models and Options
Consider the following options when ordering and configuring the SEL-421.
➤ Chassis size
➢ 3U, 4U, and 5U
(U is one rack unit—1.75 inches or 44.45 mm)
➤ Main board I/O
➢ Main Board A:
Contact inputs: 5 independent and 2 common inputs
(programmable pickup threshold);
Contact outputs: 2 standard Form A, 3 standard
Form C, and 3 High-Current Interrupting Form A
outputs
➢ Main Board B:
Contact inputs: 5 independent and 2 common inputs
(level sensitive and optoisolated);
Contact outputs: 2 standard Form A, 3 standard
Form C, and 3 High-Current Interrupting Form A
outputs
➤ Additional I/O board (for 4U and 5U chassis)
➢ INT1:
Contact inputs: 8 independent inputs (programmable
pickup threshold);
Contact outputs: 13 standard Form A and 2 standard
Form C outputs
➢ INT2:
Contact inputs: 8 independent inputs (level sensitive
and optoisolated);
Contact outputs: 13 standard Form A and 2 standard
Form C outputs
➢ INT3:
Contact inputs: 18 common (2 groups of 9) and
6 independent inputs (level sensitive and optoisolated);
Contact outputs: 4 high-current interrupting
Form A outputs
➢ INT4:
Contact inputs: 18 common (2 groups of 9) and 6
independent inputs (level sensitive and optoisolated);
Contact outputs: 6 Fast High-Current Interrupting
Form A and 2 standard Form A outputs
➢ INT5:
Contact inputs: 8 independent inputs (programmable
pickup threshold);
Contact outputs: 8 Fast High-Current Interrupting Form
A outputs
NOTE: The SEL-421-0 and the
SEL-421-1 do not support Main
Board B.
NOTE: The SEL-421-0 and the
SEL-421-1 do not support I/O boards
INT2, INT3, INT7, and INT8.
Courtesy of NationalSwitchgear.com