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GEH-5201, Synchronous-motor Control
SECTION 8 - CR192 jlSPM Programming Instructions
8.3 Explanation of standard
set-points
Each set-point has a specific purpose and care must be
taken when programming each one. The /<SPM checks each
entry to make sure that the value entered lies within the range
Table 3
Standard set-points
Parameter Number
Parameter
1
TRIP PF
2
PF DELAY
3
STALL TIME
4
RUN TIME
5
FULL LOAD CURRENT
6
LOCKED ROTOR CURRENT
7
SYNCHRONOUS SLIP
8
LINE FREQUENCY
9
C.T RAT lOt
10
RESYNC/PF TRIP
SUPPRESSION
11
FCX DELAY
shown in Table 2; however, the /<SPM cannot detect if a particu-
lar set-point is safe for use with a particular motor.
NOTE: It is the operator's responsibility to insure that
the set-points are correct for the operator's motor. Im-
proper entry of any set-paint parameter may cause
faulty motor protection.
Function
The trip power factor set-paint is the value of lagging power factor that will
cause a trip or a resynchronizing attempt during motor operation. For example:
if the trip power factor is set at 0.85 lagging. the I,SPM will trip if the power factor
falls below 0.85 for a time longer than the PF delay set-point (Always enter
three digits plus decimal point)
The power factor delay set-paint is the time delay that will elapse before the
I,SPM will operate during a power factor trip condition. If the PF delay is set for
three seconds the I'SPM will allow the motor to continue to operate for three
seconds before tripping. (Two digit entry, plus decimal.)
This set-paint determines the allowable time that power may be applied to the
motor during locked rotor conditions. This information may normally be found
on the motor control data sheet (Three digit entry, plus decimal.)
Run time
IS
the time that the motor may run at 50 percent speed and is
expressed as a multiple of the allowable motor stall time. For example: if the
motor stall time is 10 seconds and the run time set-paint is programmed at 3,
then the motor can run for 30 seconds at 50 percent speed. (Three digit entry,
plus decimal.)
This set-paint is the motor-nameplate, full·load current. It is related to the
C.T. ratio (number 09) listed in this table. Depending on the value of the C.T.
ratio, the set-point that is entered here may cause an invalid full-load current
error until the C.T. ratio is changed. The proper range of currents may be
determined by dividing the value of the entry by the C.T. ratio and if the result
is within the range of two to five amperes, the value entered will be ac-
cepted. Always enter full load current (no decimal).
The value of locked-rotor current
IS
expressed as a multiple of the motor full-
load current. For example, if the motor full load current is 100 amperes and the
locked rotor current is 550 amperes. then the locked rotor current should be
entered as 5.5 (550/100
=
5.50). (Enter three digits, plus decimal.)
The value stored here is the slip at which the I,SPM will close the field contactor.
It is expressed as percent slip For example, if 5.5 is entered as the set-point,
the I,SPM will close the field contactor when the motor reaches 94.5 percent of
synchronous speed. (100 percent Speed - 94.5 percent Speed
=
5.5 percent
SLIP). (Enter two digits, plus decimal.)
This set-point is simply the value of the local power frequency and can be 25- *,
50- or 50-Hertz.
The ratio of the current transformers supplied with the starter should
always be entered in this set-point. The value entered here affects the valid
range of motor full-load current, that may be entered in set-paint number
05 above. Enter only primary amperes. Secondary of 5 amperes is assum-
ed.
0
=
Ride thru mode.
1
=
Resync (field removal) mode.
2
=
Ride-thru plus PF Trip suppression below 50 percent rated line current.
3
=
Resync Mode plus PF Trip suppression below 50 percent rated line current.
Set time to enable Power Factor Protection and Relay FCX Operation, timing
begins with Relay FAR Operation. Set between 1 and 6 seconds (one digit
only).
t Do NOT try to store new full-load current before new C.T. Ratio is entered, or vice versa.
* Contact factory for 25-Hertz applications.
30
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