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CVHE-SVU01E-EN
76
Restart Inhibit.
This function provides short cycle
protection for the motor, and
indirectly also short cycling
protection for the starter since the
starter is designed to operate the
motor under all the conditions of
motor performance.
The operation of the restart inhibit
function is dependent upon two
setpoints. The Restart Inhibit Free
Starts (1-5, 3 default), and the Restart
Inhibit Start to Start Timer (10-30 min,
20 default). These settings are
adjustable via the service tool.
Restart Inhibit Free Starts
This setting will allow a number of
rapid restarts equal to its value. If the
number of free starts is set to “1”,
this will allow only one start within
the time period set by the Start to
Start Time Setting. The next start will
be allowed only after the start to start
timer has expired. If the number of
free starts is programmed to “3”, the
control will allow three starts in rapid
succession, but thereafter, it would
hold off on a compressor start until
the Start to Start timer expired. i.e.
with 3 free starts and 20 min. restart
inhibit settings, it will take 60
minutes of run time to restore the
total of 3 free starts.
Restart Inhibit Start to Start
Time Setting
This setting defines the shortest
chiller cycle period possible after the
free starts have been used. If the
number of free starts is programmed
to “1”, and the Start to Start Time
Setting is programmed to 10
minutes, then the compressor will be
allowed one start every 10 minutes.
The start-to-start time is the time from
when the motor was commanded to
energize to when the next command
to enter prestart is given.
Clear Restart Inhibit
A Clear Restart Inhibit “button” is
provided within Settings; Manual
Override on the DynaView display.
This provides a way for an operator
to allow a compressor start when
there is a currently active Restart
Inhibit that is prohibiting such a start.
The “button” press will have no
other function than to remove the
restart inhibit if there is one active. It
does not change the count of any
internal restart inhibit timers or
accumulators. command, but is
inhibited, pending the expiration of
the timer.
The restart inhibit function, setpoints
and clear features exist for each
compressor and operate
independently of other compressors
on that chiller.
During the time the start is inhibited
due to the start-to-start timer, the
DynaView shall display the mode
‘Restart Inhibit’ and the also display
the time remaining in the restart
inhibit.
A “Restart Inhibit Invoked” warning
diagnostic will exist when the
attempted restart of a compressor is
inhibited.
If all three motor winding
temperatures are less than the
“Restart Inhibit Temperature”
Setpoint (default 165°F/74°C) then
restart is allowed.
Restart inhibit mode exist when at
least one of the three motor winding
temperatures is greater than or equal
to the “Restart Inhibit Temperature”
Setpoint but less than 265°F/129.4°C.
Restart inhibit mode is entered until
all three motor winding temperatures
are less than the ‘Restart Inhibit
Temperature’ Setpoint
Note: When one of the three motor
winding temperatures is 265°F/
129.4°C or greater, a High Motor
Winding Temperature diagnostic
shall be called.
Note: When the start is inhibited by
the restart inhibit function, the time
remaining will be displayed along
with the restart inhibit mode.
Machine Protection
and Adaptive
Control