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SECTION 5 - Optional Features
5.1 General
The CR192 {tSPM may be supplied with several options
as described below. If required, these options MUST BE
SPECIFIED when ordering. See Section 7 for ordering
options.
5.2 Exciter voltage check
protection
Connecting the exciter output to {tSPM Terminals +VE and
-VE through a separate resistor assembly will provide exciter
voltage check protection when that option is supplied. (Figure
25.) This will not allow the motor to be started if exciter voltage
is not up, but the {tSPM will not require a reset. If exciter
voltage is lost while the motor is running, the !,SPM will trip
the motor and will require a reset before motor can be
restarted. "CHECK EXCITER" will be displayed until reset.
See Section 8 for programming the set-points.
This function is supplied for equipment that has exciters
energized prior to starting the motor. If the exciter is designed
to be energized with motor starting, as with shaft-connected
rotating exciters, either order field current loss protection
described in Section 5.4 below, or a separate voltage relay for
voltage check protection.
5.3 Exciter voltage display
By addressing the exciter voltage display function, the
exciter voltage will be flashed digitally onto the display. To
display exciter voltage press "SHIFT" then "7" key. To go
back to normal display, press any key. Input is required to
Terminals +VE and -VE per Section 5.2
NOTE: Exciter voltage cannot be displayed unless
this option is supplied. Return to normal display by
pressing any key.
5.4 Field current loss
protection
Field current loss protection is available when this option is
supplied and when the separately supplied current sensor
(D.C.C.T.) and Calibration Module (C.M.) assemblies are
connected. This protection trips the motor if the field current
drops below the programmed set-point after the motor has
synchronized. If trip occurs, "FIELD-CURRENT LOSS" is
displayed. See Section 8 for programming instructions.
5.5 Field current display
Field current may be displayed digitally if this option is
ordered. It becomes the third normally displayed value (along
with
po~r
factor and line current). The sa.me
se~arate co~po
nents used in the field current loss protection option (Section
5.4) are required.
5.6 Incomplete sequence
protection
If the motor does not synchronize within the time pro-
grammed in the incomplete sequence set-point, the motor will
trip and "INCOMPLETE SEQUENCE TRIP" will be displayed.
The {tSPM must be manually reset before the motor can be
restarted. This can be accomplished by pressing any key on
the keypad.
5.7 Power factor regulation
option
The applications requiring power factor regulation are
discussed in Section 3.2.4. The CR192 {tSPM outputs a control
signal to an external proportional SCR exciter. The regulator has
three adjustable set-paints that can be changed while the motor
is running to facilitate regulator tune-up. See Figure
20.
These
are the only three parameters that can be changed while the
motor is running. The three parameters are as follows:
1. Regulator Set-point. The desired power factor set-point
for regulation is adjustable over the range of leading power
factors.
2. Regulator Gain. This adjustment is provided to allow
optimum regulator response without instability.
3. Regulator Floor. A floor adjustment is provided that
overrides the regulator if the regulator causes the field current to
dip too low.
Certain conditions of operation require a floor so that the
motor power factor will not become unstable if the field current is
drastically reduced.
When the floor overrides the regulator, the power factor
moves in a more leading condition than the regulator set-point.
As the load and/or system force the motor power factor toward
the lagging condition such that the power factor falls below the
regulator set-point, the regulator will once again take control and
boost the field above the floor so that the power factor will not dip
below the set-point.
5.7.1 Regulator tune-up Instructions
Following these instructions will permit tune-up of the
regulator during the initial start·up of the motor.
21
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