Schweitzer Engineering Laboratories, Inc.
SEL-2241 Data Sheet
3
Outputs
Refer to
for output contact rat-
ings and
for terminal assignments. Configure
the contact output under SystemTags (Contact Outputs
Tab) in
AC
SEL
ERATOR
RTAC. You can change the name
of the point, create an alias tag name, and initialize status
values. The RTAC will use the initialized value until run
time, when it uses the actual value.
shows that a trip coil has a resistive and induc-
tive component. After a trip output has been closed for a
long time, the current settles to a steady-state value.
When the trip output opens, it tries to interrupt the induc-
tive current that wants to continue to flow (V = L di/dt).
This attempted interruption of current causes a large
voltage spike that can turn into an arc. When the contacts
bounce during the arc, they often weld closed. SEL has
designed, tested, and specified the outputs for this appli-
cation to prevent any such welding. See the
Figure 4
Inductive Interrupt of a Trip Output
LED Indicators
In addition to LEDs representing module status and com-
munications activity, the SEL-2241 has three user-pro-
grammable bi-color LEDs. Configure these LEDs under
SystemTags (LEDs Tab) in
AC
SEL
ERATOR
RTAC.
Field Serviceability
You can upgrade RTAC firmware and custom program-
ming in the field or remotely over Ethernet. Self-tests
provide status indication of errant conditions that can
occur in the RTAC. You can map one or a combination of
these or other status indications to the alarm contact to
create a diagnostic alarm.
Module Replacement
To replace the SEL-2241 RTAC, perform the following
steps.
Step 1. Back up all RTAC settings. See
Section 1:
Getting Started
in the
SEL-5033 Instruction
Manual
for instructions on how to back up and
restore RTAC projects.
Step 2. De-energize any power source connected to the
power coupler(s) in the Axion node.
Step 3. Loosen retaining screws and remove the
terminal strip for the alarm contact. Disconnect
all communications cables.
Step 4. Loosen the chassis retaining screw at the top of
the module.
Step 5. Tip the top of the module away from the chassis
and lift it from the bottom lip.
Step 6. Install the new module according to the
applicable mechanical installation instructions
in this section.
Step 7. Make all necessary connections to the module
according to the applicable connection
instructions in this section.
Step 8. Apply power to the Axion node.
Step 9. Use IP address 172.29.131.1 to access the RTAC
web interface through the supplied USB cable.
See
Section 7: Security and Account
Management
in the
SEL-5033 Instruction
Manual
for RTAC web password setup. Also
enable all necessary communications ports.
Step 10. Download the settings project from
AC
SEL
ERATOR
RTAC.
Real-Time Clock Battery Replacement
The only field-replaceable component is the real-time
clock battery, which cannot be recharged. A lithium bat-
tery powers the clock (date and time) during loss or
removal of the external power source. The battery is a
3 V lithium coin cell, Rayovac no. BR1632 or equiva-
lent. At room temperature (25°C), the battery will oper-
ate nominally for ten years. When the device receives
power from an external source, the battery experiences a
low self-discharge rate. Thus, battery life can extend well
beyond ten years.
To replace the real-time clock battery, perform the fol-
lowing steps.
Step 1. Follow the
instructions
to expose the circuit board.
Step 2. Locate the battery clip (holder) on the board.
Step 3. Carefully remove the battery from beneath the
clip. Properly dispose of the old battery.
125 Vdc
