Danfoss VLT HVAC Series User Manual

3.3.8 Trip at Motor Speed Low Limit
In par.4-11 Motor Speed Low Limit [RPM] and par.4-12 Motor Speed Low Limit [Hz] , it is possible to set a minimum speed for the motor in order to
ensure proper oil distribution.
In some cases, e.g., if operating in current limit because of a defect in the compressor, the output motor speed can be suppressed below Motor Speed
Low Limit. To prevent damage to the compressor, it is possible to set trip limit. If the motor speed drops below this limit, the adjustable frequency drive
will trip and issue an alarm (A49).
Reset will take place according to the selected function in par.14-20
Reset Mode .
If the trip must take place at a rather exact speed (RPM), it is recommended to set par.0-02
Motor Speed Unit for RPM and use slip compensation, which
can be set in par.1-62
Slip Compensation .
NOTE!
To achieve the highest accuracy with the slip compensation, an Automatic Motor Adaptation (AMA) should be performed. To be enabled
in par.1-29
Automatic Motor Adaptation (AMA) .
NOTE!
Trip will not be active when using a normal stop or coast command.
1-86 Trip Speed Low [RPM]
Range: Function:
0 RPM* [0 - par. 4-13 RPM] If the trip speed is set to 0, the function is not active.
NOTE!
This parameter is only available if par.0-02
Motor Speed Unit is set to [RPM].
1-87 Trip Speed Low [Hz]
Range: Function:
0.0 Hz* [0.0 - par. 4-14 Hz] If the trip speed is set to 0, the function is not active.
NOTE!
This parameter is only available if par.0-02
Motor Speed Unit is set to [RPM].
VLT
®
HVAC Drive Programming Guide 3 Parameter Description
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark 3-27
3

Danfoss VLT HVAC Series Specifications

General

Protection Features	Overcurrent, Overvoltage, Undervoltage, Overtemperature, Short circuit
Communication Interfaces	Profibus, Ethernet
Cooling Method	Forced convection
Ambient Temperature	-10°C to +40°C
Enclosure Rating	IP20, IP21, IP55
Output Voltage	0 - 100% of supply voltage