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© 2018 Littelfuse Fresh Water Pumping
Littelfuse.com/Pump-Protection
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Three-Phase Pump Protection
Fully Programmable
777-P2 / 777-KW/HP-P2 SERIES INSTALLATION INSTRUCTIONS
Programming
To program prior to installation, connect the 9V battery cable
to the pins on the left side of the unit (when looking at the
display), and then attach a standard 9V battery to the cable. The
9V battery cable is keyed for proper installation. If the cable is
connected improperly, the unit will not power its display. DO
NOT connect the battery when line voltage is present. The unit
cannot be tested for proper operation or communications using
a 9V battery. For testing purposes, 3-phase power must be used
with a minimum voltage of 200VAC. Follow all safety warnings
when dealing with hazardous voltages.
1. Rotate the MODE SELECT switch to the parameter to be
programmed. It is recommended that PWS be programmed
first on the KW/HP versions.
2. Press and hold the RESET/PROGRAM button.
3. While holding the RESET/PROGRAM button, rotate the
DISPLAY/PROGRAM knob until the proper setting for the
parameter that is being programmed is displayed.
4. Release the RESET/PROGRAM button. This stores the new
parameter in the nonvolatile memory. If the number changes
back to what is was before programming, then the tamper
guard is on and will need to be unlocked before programming
can be completed. (See Tamper Guard section in the install
manual if necessary.)
5. Continue steps 1-4 until all parameters are programmed.
Programmable Parameters
The following settings MUST be programmed by the user in
order to provide proper protection for the application. Settings
vary by situation and application and should be selected
and tested for each unique installation. All parameters are
actual values except for the VUB and CUB settings; these are
programmed as percentages. The range each parameter can
be programmed is found in the electrical specifications table.
Failure to program all setpoints could result in nuisance tripping
or prevent the device from protecting the motor. Always use the
proper CTs for the motor full-load amperage (FLA).
LV/HV
- Low Voltage/High Voltage. The recommended settings
for LV (low voltage) and HV (high voltage) according to the
NEMA MG1 standard are ±10% of the motor’s nameplate
voltage. Generally, the motor manufacturer should be contacted
to verify these limits. High and low voltage trips are based on
average voltage measured. Never set LV higher than HV.
Example:
Nameplate voltage = 230 V
LV = 90% x 230 =207 V
HV = 110% x 230 = 253 V
VUB -
Voltage Unbalance. The NEMA MG1 standard says a
motor should not be operated above a 1% voltage unbalance
without derating the motor. Most utility supplied power
sources have a difficult time sustaining a 1% VUB. The motor
manufacturer should be consulted for an exact VUB setting.
Setting VUB to 999 will disable voltage unbalance protection,
but will not disable voltage single-phase protection. Voltage
unbalance is calculated as follows:
%Voltage Unbalance = [(Maximum deviation from the
average)/Average] x 100%
Example:
Measured line-line voltages = 203, 210, and 212.
The average = (203+210+212)/3 = 208.3. The maximum
deviation from the average is the greatest difference between
the average voltage (208.3) and any one voltage reading:
212-208.3 = 3.7, 210-208.3 = 1.7 and 208.3-203 = 5.3. The
maximum deviation from the average is 5.3, thus voltage
unbalance = 5.3/208.3 x 100 = 2.5%.
MULT -
(multiplier) setting is found in Table 8 (Table 9 for
-LR version, Table 10 for -MLR version). The MULT setting is
determined by the number of passes of the motor leads or
the size of external CTs and the full-load amps of the motor
the unit will be monitoring. MULT sets the trip point range for
overcurrent and ground fault current faults. Set MULT first, then
set OC and GF.
OC -
Overcurrent. Is typically set to the service-factor amperage
(SFA) of the motor or 100-135% of motor full-load amps (FLA),
which are determined by the motor manufacturer. If any one leg
exceeds the OC setting, the unit will trip according to the Trip
Class (TC) settings.
NOTE:
When using external CTs, do not set OC greater than the
thermal rating of the CTs
UC -
Undercurrent (for non-KW/HP versions). Is most commonly
set to 80% of the full-load amperage (FLA) of the motor. This is
usually adequate for protection of loss of load for many pumps
and motors, including submersibles. If the motor is drawing less
than full-load amperage, then the UC may be set lower than
80% of FLA for adequate protection. Centrifugal/booster pumps
may have to be set to something higher than 80% of FLA for
adequate protection. UC can be set to 0 if UC protection is not
desired. The unit examines average current to determine if an
undercurrent trip condition exists. The value must be lower than
OC.
