Preventing Motor From Stalling (Current Limit) - YASKAWA VS mini J7 Series Instruction Manual

Preventing Motor from Stalling (Current Limit)

Automatically adjusts the output frequency and output current according to
the load to continue operation without stalling the motor.
• Stall prevention (current limit) level during acceleration (n56)
Sets the stall prevention (current limit) level during acceleration in units of
1% (Inverter rated current = 100%).
Factory setting: 170%
A setting of 200% disables the stall prevention (current limit) during
acceleration. During acceleration, if the output current exceeds the value set
for n56, acceleration stops and frequency is maintained. When the output
current goes down to the value set for n56, acceleration starts.
MOTOR CURRENT
n56
OUTPUT
FREQUENCY
In the constant output area [output frequency > max. voltage output
frequency (n11)], following equation automatically decreases the stall
prevention (current limit) level during acceleration.
Stall prevention (current limit) level
during accel in constant output area
Stall prevention (current limit)
=
level during accel (n56)
Stall prevention level
during acceleration
†
TIME
TIME
*
Max. voltage
output frequency
n11
*Stops the acceleration to prevent the motor from
stalling.
†Release width (hysteresis) of stall prevention
during accel is approx. 5% of inverter rated
current.
Max. voltage output frequency (n11)
Output frequency
Stall prevention during accel
(n56)
Stall prevention limit during accel
(40% of n56)
Output frequency
69