Franklin 2007 ユーザーズマニュアル

ページ / 75
Application – Three-Phase Motors
All Franklin three-phase submersible motors are suitable 
for full-voltage starting. Under this condition the motor 
speed goes from zero to full speed within a half second 
or less. The motor current goes from zero to locked rotor 
amps, then drops to running amps at full speed. This 
may dim lights, cause momentary voltage dips 
to other electrical equipment, and shock power 
distribution transformers.
In some cases the power companies may require 
reduced-voltage starters to limit this voltage dip. There 
are also times when reduced-voltage starters may be 
desirable to reduce motor starting torque thus reducing 
the stress on shafts, couplings, and discharge piping. 
Reduced-voltage starters also slow the rapid acceleration 
of the water on start-up to help control upthrust and 
water hammer.
Reduced-voltage starters may not be required if the 
maximum recommended cable length is used. With 
maximum recommended cable length there is a 5% 
voltage drop in the cable at running amps, resulting in 
about 20% reduction in starting current and about 36% 
reduction in starting torque compared to having rated 
voltage at the motor. This may be enough reduction in 
starting current so that reduced-voltage starters are  
not required.
Three-Lead Motors: Autotransformer or solid-state 
reduced-voltage starters may be used for soft-starting 
standard three-phase motors. 
When autotransformer starters are used, the motor 
should be supplied with at least 55% of rated voltage to 
ensure adequate starting torque. Most autotransformer 
starters have 65% and 80% taps. Setting the taps on 
these starters depends on the percentage of the    
maximum allowable cable length used in the system. 
If the cable length is less than 50% of the maximum 
allowable, either the 65% or the 80% taps may be used. 
When the cable length is more than 50% of allowable, 
the 80% tap should be used. 
Six-Lead Motors: Wye-Delta starters are used with  
six-lead Wye-Delta motors. All Franklin 6" and 8"    
three-phase motors are available in six-lead Wye-Delta 
construction. Consult the factory for details and availability. 
Part winding starters are not compatible with Franklin 
Electric submersible motors and should not be used. 
Wye-Delta starters of the open-transition type, which 
momentarily interrupt power during the starting cycle, are 
not recommended. Closed-transition starters have no 
interruption of power during the start cycle and can be 
used with satisfactory results. 
Reduced-voltage starters have adjustable settings 
for acceleration ramp time, typically preset at 30  
seconds. They must be adjusted so the motor is at 
full voltage within THREE SECONDS MAXIMUM to 
prevent excessive radial and thrust bearing wear.
If Subtrol-Plus or SubMonitor is used the 
acceleration time must be set to TWO SECONDS 
MAXIMUM due to the 3 second reaction time of the 
Subtrol-Plus or SubMonitor.
Solid-state starters AKA soft starts may not be 
compatible with Subtrol-Plus/SubMonitor. However, 
in some cases a bypass contactor has been used. 
Consult the factory for details.
During shutdown, Franklin Electric’s 
recommendation is for the power to be removed, 
allowing the pump/motor to coast down. Stopping 
the motor by ramping down the voltage is possible, 
but should be limited to three (3) seconds maximum.
Franklin Electric offers three different types of motors for 
non-vertical applications.
1. The 
Booster motors are specifi cally designed for 
booster applications. They are the “Best Choice” 
for sealed Reverse Osmosis applications.
These motors are the result of two years of focused 
development and bring additional value and durability 
to booster module systems. These motors are 
only available to OEMs or Distributors who have 
demonstrated capability in Booster Module systems 
design and operation and adhere to Franklin’s 
Application Manual requirements.
2. The 
Hi-Temp motors have many of the internal 
design features of the Booster motor. It’s additional 
length allows for higher temperature handling and 
the Sand Fighter sealing system provides greater 
abrasion resistance. One or both of these conditions 
are often experienced in open atmosphere 
applications such as lakes, ponds, etc.
3. The 
Standard Vertical Water Well (40-125 hp) 
motors can be adapted to non-vertical applications 
when applied per the below guidelines. However, 
they will be more sensitive to application variances 
than the other two designs.
All of the above motors must be applied per the 
guidelines listed below. In addition, for all applications 
where the motor is applied in a sealed system, a 
Submersible Motor Booster Installation Record (Form 
3655) or its equivalent must be completed at startup and 
received by Franklin Electric within 60 days. A sealed 
system is one where the motor and pump intake are 
mounted in a sleeve and the water feeding the pump 
intake is not open to the atmosphere.
Reduced Voltage Starters
Inline Booster Pump Systems
35