Siemens MJ-4A Installation And Operation Manual page 28

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Setting Up the MJ-4A & MJ-4B Control Panel
ondary voltage to 115, 120, or 125 volts. See U2 PT and P2
PT data items above. Also see Section 5.3.2.
4.3.13 NeutOvRun (Neutral Overrun)
The Neutral Overrun data item keeps the tap motor on for
a specified amount of time when making a tap change
into the neutral tap position. This ensures that the revers-
ing switch is always closed in order to prevent the con-
tacts from corroding due to capacitive discharge. For
regulators with a TLG mechanism set to 2.0 seconds. For
regulators with a TLF mechanism set to 1.7 seconds.
4.3.14 Min/Max Reset
The Min/Max Reset data item resets Meter and Demand
max/min values in the microprocessor to current instanta-
neous values. This function is useful when setting up the
microprocessor for the first time, or when you want to
reset electronically-maintained values.
Note: Do not use this function unless you want to
reset all Meter and Demand min/max values;
to reset selected values, use the Cancel/Reset
key described in Chapter 2.
To request that Meter and Demand Max/Min values be
reset, view Reset Max/Min; use the Change key and the
Scroll keys to change the default N(o) to Y(es). Then press
the Save key to complete the change process.
4.3.15 Version
Main Processor software version NN.NNNN. This data
item displays the installed version of the microprocessor
control program.
4.3.16 Memo 1 and Memo 2
These two data items allow you to record installation-spe-
cific information that can be viewed at a later time. For
example, you might wish to use one Memo to document
the regulator's serial number, and the other Memo to doc-
ument its location. This information could then be viewed
by a remote operator via a communications link.
To enter data into these data items, view the <CONFIG-
URE> Menu; then use the Scroll keys to view Memo 1 or
Memo 2. The display screen responds by flashing the
"blank" character ( ) in the leftmost position of the ten-
character Memo field. This indicates the character to be
changed. Use the and
and numeric characters until the desired character is pre-
sented on the display screen. Then press the
move the cursor to the next character to the right, and so
on until all ten characters of the Memo have been entered.
When you have completed entering the Memo, press the
Save key to complete the change.
Valid characters are A-Z; 0-9; space; comma; semi-colon;
period; dash; slash; ampersand (&), and the # character.
Default is for Memo 1 to contain the regulators serial num-
ber and for Memo 2 to contain the initials of the control
panel tester.
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keys to step through the alpha
key to
The <ADV CONFIGURE> Menu
4.3.17 Meter Volts (Meter Scaling)
The Meter Volts data item determines which voltage is
presented on the display screen. You can choose either
the Primary side (system voltage—e.g., 7620 V) or the
Secondary side (120 V nominal).
Specify PRI if you wish to monitor the system-level volt-
age; specify SEC if you wish to monitor voltage scaled to
the nominal 120 volt range. Voltages in the <METER>
Menu are displayed according to the Meter Volts setting.
Note: Power and energy calculations are always
derived from the system-level voltage and are
not affected by the Meter Volts setting.
4.3.18 I Threshold % (Low Current Threshold)
The I Threshold % data item defines a threshold for load
current magnitude, below which automatic mode tap
changes are inhibited. This threshold is defined as a per-
centage of the CT primary rating. (See CTratio above.)
For example, in the case of a regulator with a CTratio of
200:0.2, the CT primary rating would be 200 A. If you
specify I Threshold % = 4, you are defining a low current
threshold of 8 A. (4%*200 A = 8 A).
To set the low current threshold, view I Threshold %: and
specify a percentage of the full scale CT primary rating.
4.3.19 I Shift (Current Shift)
The I Shift data item compensates for system current-to-
voltage phase differences. Consult the factory for proper
application of this data item. (Note: This data item is pri-
marily intended for use with Load Tap Change (LTC) trans-
formers.)
4.3.20 I Load Max (Maximum Load Current)
This item specifies the Maximum Load Current as a per-
centage of the Full Load Current. When the load current
(Ild) exceeds the Maximum Load Current, the MJ-4 acti-
vates the Overcurrent Alert condition.
4.3.21 PT Threshold (Potential Transformer
Threshold)
The PT Threshold data item defines a low-voltage thresh-
old. This parameter allows you to specify a voltage level
below which automatic mode tap changes will be inhib-
ited.
4.3.22 Time and Date Items
Time (Time of Day)
The Time data item allows you to set the real-time clock.
Specify the present time, TIME: HH:MM:SS A/P (e.g.,
04:34:54P).
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