U.2.7
Date Code 20020501
User’s Guide
SEL-421/SEL-421-1 Relay
Installation
Shared Configuration Attributes
Standard Control Outputs
NOTE:
You can use ac or dc circuits
with Standard control outputs.
The Standard control outputs are “dry” Form A contacts rated for tripping
duty. Ratings for Standard outputs are 30 A make, 6 A continuous, and 0.5 A
or less break (depending on circuit voltage). Standard contact outputs have a
maximum voltage rating of 250 Vac/330 Vdc. Maximum break time is 6 ms
(milliseconds) with a resistive load. The maximum pickup time for the
Standard control outputs is 6 ms.
shows a
representative connection for a Form A Standard control output on the main
board I/O terminals.
Figure 2.5
Standard Control Output Connection.
See
Control Outputs on page U.1.11 in the User’s Guide
for complete
standard control output specifications.
Hybrid (High-Current-Interrupting) Control Outputs
CAUTION:
Equipment damage can
result from connecting ac circuits to
Hybrid (high-current-interrupting)
control outputs. Do not connect ac
circuits to Hybrid control outputs. Use
only dc circuits with Hybrid control
outputs.
The Hybrid (high-current-interrupting) control outputs are polarity dependent
and are capable of interrupting high-current, inductive loads. Hybrid control
outputs use an IGBT (Insulated Gate Bipolar Junction Transistor) in parallel
with a mechanical contact to interrupt (break) highly inductive dc currents.
The contacts can carry continuous current, while eliminating the need for heat
sinking and providing security against voltage transients.
With any hybrid output, break time varies according to the L/R (circuit
inductive/resistive) ratio. As the L/R ratio increases, the time needed to
interrupt the circuit fully increases also. The reason for this increased
interruption delay is that circuit current continues to flow through the output
MOV after the output deasserts, until all of the inductive energy dissipates.
Maximum dropout (break) time is 6 ms with a resistive load, the same as for
the Standard control outputs. The other ratings of these control outputs are
similar to the Standard control outputs, except that the Hybrid outputs can
break current as great as 10 A. Hybrid contact outputs have a maximum
voltage rating of 330 Vdc.
The maximum pickup time for the Hybrid control outputs is 6 ms.
shows a representative connection for a Form A Hybrid control output on the
main board I/O terminals.
OUT04
+
O7
O8
Summary of Contents for SEL-421
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