Franklin 2007 ユーザーズマニュアル

9.  Controls-Soft Starters and VFDs: Reduced voltage 

starters and variable speed drives (inverter drives) 
may be used with Franklin three-phase submersible 
motors to reduce starting current, upthrust, and 
mechanical stress during start-up. The guidelines 
for their use with submersible motors are different 
than with normal air cooled motor applications. 
Refer to the Franklin Electric Application, Installation 
and Maintenance (AIM) Manual Reduced Voltage 
Starters section or Variable Speed Submersible 
Pump Operation, Inverter Drives sections for specifi c 
details including required fi ltering.

10.  Motor Overload Protection: Submersible motors 

require properly sized ambient compensated 
Class 10 quick-trip overloads per Franklin’s AIM 
Manual guidelines to protect the motor. Class 20 
or higher overloads are NOT acceptable. Franklin’s 
SubMonitor is strongly recommended for all large 
submersibles since it is capable of sensing motor 
heat without any additional wiring to the motor. 
Applications using Soft Starters with a SubMonitor 
require a start-up bypass - consult the factory for 
details. SubMonitor can not be used in applications 
using a VFD control.

11.  Motor Surge Protection: Properly sized, grounded 

and dedicated motor surge arrestors must be 
installed in the supply line of the booster module as 
close to the motor as possible. This is required on 
all systems including those using soft-starters and 
variable speed drives (inverter drives).

12.  Wiring: Franklin’s lead assemblies are only sized 

for submerged operation in water to the motor 
nameplate maximum ambient temperature and 
may overheat and cause failure or serious injury 
if operated in air. Any wiring not submerged must 
meet applicable national and local wiring codes and 

Franklin Cable Chart tables 16-21. (Notice: wire size, 
wire rating and insulation temperature rating must be 
known when determining its suitability to operate in 
air or conduit. Typically, for a given size and rating, 
as the insulation temperature rating increases its 
ability to operate in air or conduit also increases.)

13.  Check Valves: Spring-loaded check valves must 

be used on start-up to minimize motor upthrusting, 
water hammer, or in multiple booster (parallel) 
applications to prevent reverse fl ow.

14.  Pressure Relief Valves: A pressure relief valve is 

required and must be selected to ensure that, as the 
pump approaches shut-off, it never reaches the point 
that the motor will not have adequate cooling fl ow 
past it.

15.  System Purge (Can Flooding): An air bleeder 

valve must be installed on the booster sleeve so that 
fl ooding may be accomplished prior to booster start-
up. Once fl ooding is complete, the booster should 
be started and brought up to operating pressure as 
quickly as possible to minimize the duration of an 
upthrust condition. At no time should air be allowed 
to gather in the booster sleeve because this will 
prevent proper cooling of the motor and permanently 
damage it.

16.  System Flush – Must Not Spin Pump: Applications 

may utilize a low fl ow fl ushing operation. Flow 
through the booster sleeve must not spin the pump 
impellers and the motor shaft. If spinning takes 
place, the bearing system will be permanently 
damaged and the motor life shortened. Consult the 
booster pump manufacturer for maximum fl ow rate 
through the pump when the motor is not energized.

Based on 30 °C maximum ambient with cable length of 100 feet or less.

40A

28A

56A

40A

76A

52A

100A

68A

136A

92A

69A

48A

97A

69A

132A

90A

173A

118A

236A

19A

44A

32A

64A

44A

84A

60A

112A

76A

152A

104A

76A

55A

111A

76A

145A

104A

194A

132A

263A

180A

63A

46A

74A

51A

104A

74A

145A

98A

185A

126A

109A

80A

127A

88A

180A

129A

251A

320A

320A

219A

37