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Application – All Motors
Franklin Electric submersible motors are designed to
operate with a cooling fl ow of water over and around the
full length of the motor.
If the pump installation does not provide the minimum fl ow
shown in table 6, a fl ow inducer sleeve (fl ow sleeve) must
be used. The conditions requiring a fl ow sleeve are:
Wells – Large Diameter, Uncased, Top Feeding and Screened Sections
• Well diameter is too large to meet table 6
fl ow requirements.
• Pump is in an open body of water.
• Pump is in a rock well or below the well casing.
• The well is “top-feeding” (a.k.a. cascading)
• Pump is set in or below screens or perforations.
Franklin Electric’s standard submersible motors, except
Hi-Temp designs (see note below), are designed to
operate up to maximum service factor horsepower in
water up to 86 °F (30 °C). A fl ow of 0.25 ft/s for 4" motors
rated 3 hp and higher, and 0.5 ft/s for 6 and 8" motors is
required for proper cooling. Table 6 shows minimum fl ow
rates, in gpm, for various well diameters and motor sizes.
If a standard motor is operated in water over 86 °F
(30 °C), water fl ow past the motor must be increased to
maintain safe motor operating temperatures. See
HOT WATER APPLICATIONS on page 7.
NOTE: Franklin Electric offers a line of Hi-Temp motors
designed to operate in water at higher temperatures or
lower fl ow conditions. Consult factory for details.
Water Temperature and Flow
0.25 ft/s = 7.62 cm/sec 0.50 ft/s = 15.24 cm/sec
1 inch = 2.54 cm
If the fl ow rate is less than specifi ed, then a
fl ow inducer sleeve must be used. A fl ow
sleeve is always required in an open body
of water. FIG. 1 shows a typical fl ow inducer
sleeve construction.
EXAMPLE: A 6" motor and pump that delivers
60 gpm will be installed in a 10" well.
From table 6, 90 gpm would be required to
maintain proper cooling. In this case adding
an 8" or smaller fl ow sleeve provides the
required cooling.
FIG. 1
WORM GEAR
CLAMPS
INTAKE
FLOW INDUCER
SLEEVE
SUBMERSIBLE
MOTOR
CENTERING BOLT
LOCK NUTS
INSIDE SLEEVE
CENTERING
BOLT HOLE
(3 REQUIRED)
BOTTOM END VIEW
NOTCH OUT
FOR CABLE
GUARD
SAW CUTS
CENTERING BOLTS
MUST BE LOCATED
ON MOTOR CASTING.
DO NOT LOCATE ON
STATOR SHELL.
Table 6 Required Cooling Flow
a zero head condition. This causes an uplifting or
upthrust on the impeller-shaft assembly in the pump.
This upward movement carries across the pump-
motor coupling and creates an upthrust condition in
the motor. Repeated upthrust can cause premature
failure of both the pump and the motor.
C. Water Hammer - If the lowest check valve is more
than 30 feet above the standing (lowest static)
water level, or a lower check valve leaks and the
check valve above holds, a vacuum is created in
the discharge piping. On the next pump start, water
moving at very high velocity fi lls the void and strikes
the closed check valve and the stationary water in the
pipe above it, causing a hydraulic shock. This shock
can split pipes, break joints and damage the pump
and/or motor. Water hammer can often be heard or
felt. When discovered, the system should be shut
down and the pump installer contacted to correct
the problem.
MINIMUM GPM REQUIRED FOR MOTOR COOLING IN WATER UP TO 86 °F (30 °C).
CASING OR
SLEEVE ID
INCHES (MM)
4" MOTOR (3-10 HP)
0.25 FT/S
GPM (L/M)
6" MOTOR
0.50 FT/S
GPM (L/M)
8" MOTOR
0.50 FT/S
GPM (L/M)
4 (102)
1.2 (4.5) - -
5 (127)
7 (26.5) - -
6 (152)
13 (49) 9 (34) -
7 (178)
20 (76) 25 (95) -
8 (203)
30 (114) 45 (170) 10 (40)
10 (254)
50 (189) 90 (340) 55 (210)
12 (305)
80 (303) 140 (530) 110 (420)
14 (356)
110 (416) 200 (760) 170 (645)
16 (406)
150 (568) 280 (1060) 245 (930)
Flow Inducer Sleeve
6