Switches - Siemens MJ-4A Installation And Operation Manual

2
Using the MJ-4A & MJ-4B Operator Panel and Controls
Voltage Limit Control LED Indicators
The Voltage Limit Control (VLC) indicators illuminate to
indicate that VLC is active. With the VLC upper limit acti-
vated, the VLC Upper indicator is illuminated. If the VLC
lower limit is activated, the VLC Lower indicator is illumi-
nated.
If VLC is active, and Vld is within 1 volt of the VLC limit,
the appropriate VLC and Band Indicator will both be illumi-
nated.
Voltage Reduction Control Active Indicator LED
This indicator is illuminated whenever Voltage Reduction
Control is in effect. The VRC LED indicator flashes a
unique pattern to indicate which stage, step, or set is
active, depending upon the VRC Mode as described in
Table 2.3. (See Section 4.4.3 for more information.)
VRC Indicator Flash Patterns
Table 2.3
Flashing
Pattern
Local
On Active
long-short
long-short-short
long-short-
short-short
Neutralite Indicator
The Neutralite indicator illuminates when the tap changer
is in the Neutral position. The Neutralite indicator also illu-
minates when the Neutralite Test key is pressed and held.
2.5

Switches

Power Switch
This three-position switch selects the power source for
the MJ-4 Control Panel.
• In the upper (Normal) position, the regulator Utility
(tertiary) winding provides power through the polar-
ized disconnect switch (PDS).
• In the lower (External Source) position, the External
Source terminals (described below) provide power.
• In the middle (Off) position, the Control Panel is
turned off. This is also called the By-Pass Position.
Tap Control Switches (Mode Select Switches)
Auto/Off/Manual Switch (MJ-4A)
In the MJ-4A panel, the 3 position discrete switch,has the
Center = OFF , Down = Manual and Up = Auto functional-
ities. When in Auto, the panel may be switched between
Auto-Remote or Auto-Local modes by pressing the
Remote / Local push button.
10
VRC Modes
Remote Remote Auto
MJ-X
( ) (MJ-3A)
Stage-1 Step 1 Set 1
Stage-2 Step 2 Set 2
Stage-3 Step 3
Auto/Manual Push button (MJ-4B)
This push button determines whether the MJ-4B Control
Panel is under manual control or microprocessor control.
Note that the ultimate determination of the point of con-
trol can be changed remotely if Remote Disabled is not
activated.
Tap Control Modes
• Manual / Auto Disabled (By-Pass Position), The opera-
tor has control of the regulator's tap changer motor;
automatic tap changes are disabled. In this mode, a
local operator can use the Raise and Lower switches
or push buttons to adjust the tap position or a remote
operator could control the tap motor.
• Auto Enabled. The microprocessor has control of the
tap changer motor and local manual tap changes are
disabled.
Remote / Local Push button
This push button determines whether the MJ-4 Control
Panel is under local control or remote control. Note that
the ultimate determination of the point of control is estab-
lished manually; this switch setting cannot be overridden
from a remote location.
• Remote Disabled. In this mode, a remote operator
can obtain MJ-4 Control Panel data. However, the
remote operator cannot make configuration changes
or exercise control of the tap changer motor.
• Remote Enabled. In this mode, a remote operator has
access to all functions available to the local operator,
including the ability to override automatic control of
the tap changer motor.
• This push button is common for both the MJ-4A &
MJ-4B Panels.
Raise and Lower Switches / Push buttons
When the Auto Disabled LED is ON, this discrete switch
or push buttons activate the tap changer motor to raise or
lower the tap position.
Siemens Energy, Inc.