LV-
575
x 0.90 =
51
7
HV-
575
x 1.10 =
632
VUB- Manufacturer suggest 5%
MULT-From Table No. 1, MULT = 2 (2 conductors, 1 loop)
OC- Service Factor Amperage = 18.2
UC- FLA x 0.80 = 15.9 x 0.80 = 12.7
CUB- Manufacturer suggest 5%
TC- TC = 010 (To program RD1 and RD2), then TC = J00
RD1- To protect the pump from rapid cycling and reduce the number of
starts per hour, RD1 = 10 (Display value) x 0.5 = 5
seconds
.
RD2- Since the motor is small and submerged in water it will
generally cool off quickly, RD2 = 10 x 0.5 = 5 Minutes.
MA- MA = 64 (Displayed value) x 0.158 = 10.1 Seconds.
OCTD-OCTD = 10 (Displayed value) x 0.158 = 1.58 Seconds.
RD3- The well history shows that it will fully recover in 2 hours.
RD3 = 240 x 0.5 = 120 Minutes
#RU- In this application, we know that the well will eventually recharge
itself, #RU = A.
#RF- This well is known for sand to jam the impeller, therefore “oc”
should be included so that the pump will attempt to automatically
restart after an overloaded condition. History shows that 1 start
attempt usually clears the sand out of the impeller. #RF = oc1
UCTD- UCTD = 10
GF- Because it may take several days to get a new pump motor and
schedule for maintenance personnel to remove and replace the
pump motor, GF setting of 10% of full load amperage will give the
well owner enough time to prepare for pump replacement.
GF = 56.2A x 0.10 = 5.6
#2
- Motor To Be Protected: 3Ø, 460 Volt, 25 Hp air compressor with a full load
amperage rating of 34A and maximum service factor amps of 37.4. Use the
following calculations and reasoning to determine the appropriate settings
for this application.
LV-
575
x 0.90 =
517
HV-
575
x 1.10 =
632
VUB- Standard NEMA motor = 5
MULT-From Table No. 1 = 1
OC- Service Factor Amperage = 37.4
UC- FLA x 0.80 = 34A x 0.80 = 27.2
CUB- Standard NEMA motor = 5
TC- General purpose motor = 20
RD1- Since this compressor takes about 10 seconds to bleed off excess
pressure after a shutdown, setting RD1 = 20 will allow the
compressor to unload before being restarted.
RD2- Because the motor may be hot from running in an unbalance or
single phase condition, a motor cool down time of 10 minutes,
RD2 = 10, should be appropriate.
07/25/03
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