Franklin 2007 ユーザーズマニュアル

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:

•  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.

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.

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.

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. 

1.2 (4.5)

-

-

7 (26.5)

-

-

13 (49)

9 (34)

-

20 (76)

25 (95)

-

30 (114)

45 (170)

10 (40)

50 (189)

90 (340)

55 (210)

80 (303)

140 (530)

110 (420)

110 (416)

200 (760)

170 (645)

150 (568)

280 (1060)

245 (930)

6