Sleep Mode - Danfoss VLT 8000 AQUA series Operating Instructions Manual

Sleep mode

Sleep mode makes it possible to stop the motor
when it is running at low speed, similar to a no
load situation. If consumption in the system goes
back up, the frequency converter will start the
motor and supply the power required.
NB!:
Energy can be saved with this function,
since the motor is only in operation when
the system needs it.
Sleep mode is not active if Local reference
or Jog has been selected
The function is active in both Open loop
and Closed loop.
In parameter 403 Sleep mode timer, the Sleep mode is
activated. In parameter 403 Sleep mode timer, a timer
is set that determines how long the output frequency
can be lower than the frequency set in parameter
404 Sleep frequency. When the timer runs out, the
frequency converter will ramp down the motor to stop
via parameter 207 Ramp-down time. If the output
frequency rises above the frequency set in parameter
404 Sleep frequency, the timer is reset.
= factory setting. () = display text [] = value for use in communication via serial communication port
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VLT 8000 AQUA
While the frequency converter has stopped the
motor in sleep mode, a theoretical output frequency
is calculated on the basis of the reference signal.
When the theoretical output frequency rises above
the frequency in parameter 405 Wake up frequency,
the frequency converter will restart the motor and the
output frequency will ramp up to the reference.
In systems with constant pressure regulation, it
is advantageous to provide extra pressure to the
system before the frequency converter stops the
motor. This extends the time during which the
frequency converter has stopped the motor and
helps to avoid frequent starting and stopping of the
motor, e.g. in the case of system leaks.
If 25% more pressure is required before the
frequency converter stops the motor, parameter
406 Boost setpoint is set to 125%.
Parameter 406 Boost setpoint is only active
in Closed loop.
NB!:
In highly dynamic pumping processes, it
is recommended to switch off the Flying
Start function (parameter 402).
MG.83.A2.02 - VLT is a registered Danfoss trademark