2
Using the MJ-XL Operator Panel and Controls
Siemens Power Transmission & Distribution, Inc.
7
minals. For the MJ-X
L
, pressing the U2/P2 key
toggles the test terminal voltage between U2
and P2.
Note: Press the U2/P2 key to display the exact regu-
lator voltage values coming into the panel.
Neutralite Test Key
Press this key to illuminate the Neutralite Indicator. This is
a lamp test.
Drag Hands Reset Key
Press this key to reset the electromechanical drag hands
on the regulator Position Indicator to the present tap
changer position. This also resets the electronically stored
max/min tap position values (viewable from the display).
Quick Key
The Quick key functions are to be implemented in a later
version of the MJ-X
L
Control Panel. Check the Siemens
website for updates.
2.4
Indicators
The front panel also provides user information via individ-
ual status indicators. These indicators provide a direct
means of assessing operational status.
Alert LED
This indicator is illuminated whenever one or more alert
conditions are active. The indicator may either flash or
remain on steadily.
•
If flashing, it indicates that one or more alert condi-
tions are active and have not yet been acknowledged.
•
If the Alert Indicator glows steadily, it means that a
previously-acknowledged alert condition continues to
exist.
To acknowledge an Alert, view the Alert screen with the
Alert Select button and then press the Cancel/Reset but-
ton.
Reverse Power Flow LED
The Reverse Power Flow (RPF) indicator is illuminated
when the microprocessor senses reverse power flow. The
indicator will either be off, on, or flashing depending upon
both Power Flow mode and Current direction (see Section
4.3.15 and Table 2.1 below.
When the real component of load current drops below 1%
of rated current, the RPF indicator continues to display its
previous state.
If the real component of current is less than 1% when the
MJ-X
L
Control Panel is powered up, the RPF LED is OFF
(indicates forward).
Remote Auto Inhibit LED
This indicator is illuminated when automatic tap changes
are inhibited. Either the remote operator has sent an auto-
matic inhibit command, or the Automatic Inhibit contacts
have been activated.
Band Indicator LEDs
Three Band Indicators, “High", "In Band,” and “Low,” are
located at the top of the front panel. The microprocessor
continuously compares load voltage (corrected for line
drop) against the Voltage Level and Bandwidth setpoints.
The Band Indicator LEDs show the results of this compar-
ison (see Table 2.2).
“In Band” indicates that regulator output voltage is within
voltage and bandwidth setpoints.
“High” indicates that regulator output voltage is out-of-
limits on the high side.
“Low” indicates that regulator output voltage is out-of-
limits on the low side.
In all power flow modes except Neutral Reverse, if one of
the three Band Indicators is
flashing
, it is an indication that
tap changes are being inhibited by the control program. In
Neutral Reverse, the flashing Band Indicator in conjunc-
tion with a Reverse Power Flow condition may mean that
Test
Reset
Quick
Table 2.1
Reverse Power flow Indicator Status
Power Flow Mode
RPF Indicator Status
Reverse Current
1
Forward Current
1
Neutral R
On
Off
Idle R
On
Off
Co-Gen
On
Off
Bi-Dir
On
Off
F Lock
Flashing
Off
R Lock
On
Flashing
1. (Real component) exceeds 1% rated current for 5 seconds
Summary of Contents for MJ-XL
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