Specifications

An alternative is to reduce the load level of the motor by
selecting a larger motor. However, the design of the
frequency converter puts a limit to the motor size.
Variable (Quadratic) torque applications (VT)
In VT applications such as centrifugal pumps and fans,
where the torque is proportional to the square of the
speed and the power is proportional to the cube of the
speed, there is no need for additional cooling or de-rating
of the motor.
In the graphs shown below, the typical VT curve is below
the maximum torque with de-rating and maximum torque
with forced cooling at all speeds.
Maximum load for a standard motor at 40 °C driven by a VLT
frequency converter
10 20 30 40 50 60 70 80 90 100 110
20
40
60
80
100
120
0
v %
T %
0
1)
130BA893.10
Legend: ─ ─ ─ ─Typical torque at VT load ─•─•─•─ Max torque
with forced cooling ‒‒‒‒‒Max torque
Note 1) Over-synchronous speed operation results in the
available motor torque decreasing inversely proportional with
the increase in speed. This must be considered during the
design phase to avoid overloading the motor.
Table 9.33 Maximum load for a standard motor at 40
°C
9.7
Troubleshooting
A warning or an alarm is signalled by the relevant LED on
the front of the and indicated by a code on the display.
A warning remains active until its cause is no longer
present. Under certain circumstances, operation of the
motor may still be continued. Warning messages may be
critical, but are not necessarily so.
In the event of an alarm, the trips. Alarms must be reset to
restart operation once their cause has been rectified.
This may be done in 4 ways:
1. By resetting the [RESET] on the LCP.
2. Via a digital input with the “Reset” function.
3. Via serial communication/optional fieldbus.
4. By resetting automatically using the Auto Reset
function, which is a default setting for VLT
®
HVAC
Drive, see 14-20 Reset Mode in the FC 102
Programming Guide
NOTICE
After a manual reset pressing [RESET] on the LCP, press
[Auto On] or [Hand On] to restart the motor.
If an alarm cannot be reset, the reason may be that its
cause has not been rectified, or the alarm is trip-locked
(see also Table 9.34).
CAUTION
Alarms that are trip-locked offer additional protection,
means that the mains supply must be switched off
before the alarm can be reset. After being switched back
on, the is no longer blocked and may be reset as
described above once the cause has been rectified.
Alarms that are not trip-locked can also be reset using
the automatic reset function in 14-20 Reset Mode
(Warning: automatic wake-up is possible!)
If a warning and alarm is marked against a code in the
table on the following page, this means that either a
warning occurs before an alarm, or it can be specified
whether it is a warning or an alarm that is to be
displayed for a given fault.
This is possible, for instance, in 1-90 Motor Thermal
Protection. After an alarm or trip, the motor carries on
coasting, and the alarm and warning flash on the . Once
the problem has been rectified, only the alarm continues
flashing.
NOTICE
No missing motorphase detection (no 30-32) and no stall
detection is active when 1-10 Motor Construction is set to
[1] PM non salient SPM.
No. Description Warning Alarm/
Trip
Alarm/Trip Lock Parameter Reference
1 10 V low X
2 Live zero error (X) (X) 6-01
3 No motor (X) 1-80
4 Mains phase loss (X) (X) (X) 14-12
5 DC link voltage high X
6 DC link voltage low X
General Specifications and ... Design Guide
170 Danfoss A/S © Rev. 06/2014 All rights reserved. MG11BC02
99