Vacon 100 - Underload Protection

P3.9.3.2 STALL CURRENT (ID 710)
You can set the value of this parameter between 0.0 and 2*IL. For a stall status to occur, the
current must be higher than this limit. If parameter P3.1.3.1 Motor Current Limit changes,
this parameter is automatically calculated to 90% of the current limit.
NOTE!
The value of the Stall Current must be below the motor current limit.
f
I
ID710
ID712
Stall area
Fig. 58: The stall characteristics settings
P3.9.3.3 STALL TIME LIMIT (ID 711)
You can set the value of this parameter between 1.0 and 120.0 s. This is the maximum time
for the stall status to be active. An internal counter counts the stall time.
If the stall time counter value goes above this limit, the protection causes the drive to trip.
9.9.3 UNDERLOAD PROTECTION
The motor underload protection makes sure that there is a load on the motor when the drive
operates. If the motor loses the load, a problem can occur in the process. For example, a belt
can break or a pump become dry.
You can adjust the motor underload protection with parameters P3.9.4.2 (Underload
Protection: Field Weakening Area Load) and P3.9.4.3 (Underload Protection: Zero Frequency
Load). The underload curve is a squared curve between the zero frequency and the field
weakening point. The protection is not active below 5 Hz. The underload time counter does
not operate below 5 Hz.
The values of the underload protection parameters are set in percentage of the nominal
torque of the motor. To find the scaling ratio for the internal torque value, use the data in the
name plate data of the motor, the motor nominal current and the nominal current of the
drive IH. If you use another current than the nominal motor current, the precision of the
calculation decreases.
VACON · 280 PARAMETER DESCRIPTIONS
9
TEL. +358 (0)201 2121 · FAX +358 (0)201 212 205