Stall Prevention - YASKAWA V7 Technical Manual

5.23 STALL PREVENTION

A. n092 : Stall Prevention During Deceleration
Setting
0
1
Stall prevention during deceleration automatically
adjusts the deceleration rate while monitoring the
DC bus voltage to prevent overvoltage during
deceleration.
When the motor load is large or decel time is
short, actual decel time may be longer than the
set value because of stall prevention
B. n093 : Stall Prevention Level During
Acceleration
This parameter determines the actual Drive output current level during an acceleration condition. Set in
percent of Drive rated output current.
A setting of " 200 " disables stall
prevention during acceleration. During
acceleration, if the output current
exceeds the value in n093 , acceleration
stops and frequency is maintained.
When the output current goes below the
value set in n093 , acceleration resumes.
In the constant horsepower region
[actual output frequency ≥ max. voltage
frequency (n013 )], the stall prevention
level during acceleration is changed by
the following formula:
Stall prevention level during
accel (constant horsepower)
C. n094 : Stall Prevention Level At Set Speed
This parameter determines the actual
Drive output current level while operating
at set speed (frequency). Set in percent
of Drive rated output current (see
Appendix 2).
A setting of " 200 " disables stall
prevention at set speed. During running
at set speed, if the output current exceeds
the value set in n094 , the drive will begin
to decelerate. When the output current
goes below the value set in n094,
acceleration begins, up to the set
frequency.
Function
Stall prevention during deceleration enabled
Stall prevention during deceleration disabled
FREQUENCY
.
MOTOR
CURRENT
Parameter
Constant
n093
n073
Setting
setting
OUTPUT
FREQ.
= Stall prevention level during accel x
MOTOR
CURRENT
Constant
Parameter
n074
n094
setting
Setting
OUTPUT
FREQ.
5-35
Factory setting: 0
Controls the
deceleration
time needed to
prevent over-
voltage fault.
SET
DECEL
TIME
Factory setting: See Table A3-1
Range: 30 - 200 %
Max. voltage frequency
Actual output frequency
Factory setting: 160%
Range: 30 - 200 %
TIME
t
t
t
t