I~
3.10 OPTION PROGRAMMING
Each relay can be programmed for a particular application using a
group
of
selector switches. This provides flexibility since
only
the desired features are
used and the settings can be changed at any time. Table
3-4
is a summary of the
switch options.
TABLE
3-4
OPTION SWITCH SETTINGS
FUNCTION
OPTION SWITCH SETTINGS
X
=Switch
On
0 = Switch Off
- = No Effect 81
82
83
84
85
86
87
88
Cyclic Overload Compensation
x
-
- -
0
-
- -
Immediate
Overload Warning
-
x
- - - - - -
Disable Undercurrent
- -
x
- - - - -
Emergency
Restart
- -
-
x
- - - -
Memory Defeat
- - - -
x
- - -
Motor
Temperature Compensation
- - - - -
x
- -
Voltage Compensation
- - - - - -
x
-
Enable Feeder Protection
- -
-
-
x
- -
x
Switch 81
-Cyclic
Overload Compensation
In
applications where the
motor
periodically goes into overloads such as
crushing, switches
81
should
be
on and 85 off. Motors
of
this type are
de-
signed for frequent short overloads but the relay memory would accumulate
the overloads and eventually trip. Cyclic overload compensation causes the
memory
to
discharge every
time
the
motor
recovers from
an
overload but still
allows repeat start protection from jogging. A continuous overload will still trip
according
to
the run curves (Figure
3-2).
Switch
82-lmmediate
Overload Warning
Turning this switch on will cause the auxiliary relay to be activated whenever the
relay senses
an
overload providing a useful warning signal. Since overloads are
normal during start up, this function
is
not active when the relay
is
in
start mode.
Switch
83-Undercurrent
Detection
An undercurrent condition will activate the auxiliary relay if this switch is off.
When the auxiliary relay is to be activated by a condition other than undercurrent
this switch should be set on.
Switch
84-Emergency
Restart
It may be necessary to disable the emergency restart terminals 3 and 4 to prevent
unauthorised reset of the relay after a lockout. Turning switch
84
off disables the
emergency restart feature.
Switch
BS-Memory
Defeat
Each relay incorporates a memory which simulates heat buildup
in
the motor by
accumulating previous overloads and start-ups reducing the time available for
future overloads. When the memory
is
defeated by turning switch
85
on, the unit
can be reset immediately after a trip instead
of
the normal
30
minute lockout.
Only a continuous overload or start will cause a trip when the memory is defeated.
Previous overloads and starts will have no effect.
23
Courtesy of NationalSwitchgear.com
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