NOTICE
If
parameter 4-13 Motor Speed High Limit [RPM]
or
parameter 4-14 Motor Speed High Limit [Hz]
is set to the
boost speed 4200 RPM, an oil boost may cause
unwanted staging or destaging if
parameter group 25-**
Cascade Controller
is active.
28-10 Oil Return Management
Option:
Function:
[0]
Off
No function
[1]
*
On
Oil return mechanism is active.
28-11 Low Speed Running Time
Running at low speeds for extended periods may result in
inadequate oil return to the compressor crankcase. Set this
parameter to the maximum running time the compressor is
allowed to run at a speed below 40 rps/80 Hz. If the compressor
has run below ORM Min Speed Limit and the timer has expired,
the oil return management is activated.
Range:
Function:
120 min
*
[1 - 1440
min]
28-12 Fixed Boost Interval
An oil return boost is performed at fixed time intervals to
complement the oil return boosts triggered by inadequate flow
speeds (
parameter 28-11 Low Speed Running Time
). The fixed
interval boosts ensure that oil return boosts are performed even
when no boosts have occurred due to low flow speed.
Range:
Function:
24 h
*
[1 - 168 h]
28-13 Boost Duration
Range:
Function:
60 s
*
[60 - 300 s]
This parameter controls the
duration of oil return boosts.
28-15 ORM Min Speed Limit [Hz]
Range:
Function:
80 Hz
*
[80 - 200 Hz] Minimum speed limit for activating
the Oil Return Management.
28-17 ORM Boost Speed [Hz]
Range:
Function:
120 Hz
*
[80 - 200 Hz]
Parameter 28-17 ORM Boost Speed
[Hz]
controls the speed of the
compressor during oil return boost.
3.14.2 28-4* Anti-reverse Protection
A compressor may have a preferred rotation direction and
the instructions for cabling should always be followed, but
the consequences of a reverse rotation are normally not
fatal. Set up
parameter group 28-4* Anti-reverse Protection
to prevent reverse rotation at stop by injecting a DC brake
current into the compressor a few seconds after stop
followed by the eventual coast of the compressor when
the discharge valve has closed.
NOTICE
The DC brake function is not operational before any start
function has completed. If there is an emergency stop
before the starting sequence has completed, the
compressor may rotate reverse for a short moment after
stop. Under normal circumstances, the short-cycle
protection feature ensures the correct sequence.
28-40 Reverse Protection Control
Activate a DC brake current when the compressor is stopped.
Option:
Function:
[0]
Disabled
[1]
*
Enabled
28-60 RPS
Range:
Function:
0 /s
*
[0 - 250 /s]
View the actual compressor
frequency in rps (rounds per
second).
Parameters
Programming Guide
MG18P202
Danfoss A/S © 06/2019 All rights reserved.
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