Appendix F—Pump Control Option
64
S811+ Soft Starter
MN03900001E—November 2012
Appendix F—Pump Control Option
Pump Control Option
This option is intended to reduce the potential for water
hammer in a centrifugal pump system by utilizing a starting
and stopping algorithm developed for pump control. Upon a
start command, the speed of the motor is increased, under
the control of the S811+ Soft Starter microprocessor, to
achieve a gentle start. After the speed has reached its
nominal value, the bypass contactors close and the pump
operates as with any other starter. Upon a stop command,
the bypass contactors are opened and the motor speed is
decreased in a tapered manner, to gradually slow the flow
until the motor is brought to a stop. The start and stop ramp
times are user adjustable and are to be set for the application
requirements.
Installation
Install and wire your S811+ Soft Starter per the instructions
found in the beginning of this manual.
Setup
All pump control parameters are set via the DIM or network
connection. Units configured with the pump control option
can activate this feature by selecting the pump option under
the DIM “Start Method” parameter.
Adjustment
All of the adjustments to the S811+ Premium Soft Starter are
made as noted in this user manual. The major difference
between the standard S811+ Soft Starter and Premium is
the special algorithm for gentle start and stop with
centrifugal flow loads to minimize the potential for water
hammer.
Using the DIM, set the S811+ Soft Start Configuration
parameters described below:
The
Pump Start Ramp Time
parameter adjusts the start
ramp. It has a standard range of 0.5 to 180.0 seconds. The
factory default is 20.0 seconds. The pump stop time is
adjusted by
Pump Stop
, which has a range of 5.0 to 120.0
seconds with the factory default being 10.0 seconds. (
NOTE
:
The
Stop Ramp Time
setting used in non-pump S811+’s has
no effect on units with the Pump Control Option installed if
start method is Pump Start.) These adjustments are
application dependent, and should be made to minimize any
surge or water hammer effects. Typically
Pump Stop
would
not be set short, since the stop might not differ much from a
coast-to-stop. The soft stop time adjustment may often be in
the range of 30 to 40 seconds, but needs to be set
appropriately for the system requirements. If reduction or
elimination of water hammer is not achieved, it may be
necessary to lengthen
Pump Stop
to achieve the desired
result. Note that long stop times will result in greater motor
heating than shorter stop times. This can affect the number
of start/stop cycles allowed per hour due to the S811+ Soft
Starter or motor thermal limits.
Pump Control Option
100%
tr
Start
Soft Pump Stop
Speed
Time (Seconds)
ts
Run
Coast to Stop