Acceleration and deceleration
Shortest acceleration/deceleration mode (Pr. 292 = 1, 11, Pr. 293)
● Set when you want to accelerate/decelerate the motor for the shortest time. It is desired to
make acceleration/decelerationin a shorter time for a machine tool etc. but the design values
of machine constants are unknown.
● Acceleration/deceleration speed is automatically adjusted at a start of acceleration/decel-
eration from the value of the setting value of Pr. 7 "Acceleration time" and Pr. 8 "Deceleration
time" so that acceleration/deceleration is made with the maximum torque the inverter can
output. (The setting values of Pr. 7 and Pr. 8 are not changed.)
● Either acceleration or deceleration can be made in the shortest time using Pr. 293
"Acceleration/deceleration separate selection". When the setting value is "0" (initial value),
both acceleration and deceleration can be made in the shortest time.
● Set "11" when an optional high-duty brake resistor or brake unit is connected. Deceleration
time can be further shortened.
● When the shortest/acceleration mode is selected, the stall prevention operation level during
acceleration/deceleration from the value of becomes 150% (adjustable using Pr. 61 to
Pr. 63). Setting of Pr. 22 "Stall prevention operation level" is used only during a constant
● It is inappropriate to use for the following applications.
– Machine with a large inertia such as a fan (more than 10 times). Since stall prevention
operation will be activated for a long time, this type of machine may be brought to an
alarm stop due to motor overloading, etc.
– It is desired to always perform operation with a constant acceleration/deceleration time.
Even if automatic acceleration/deceleration mode has been selected, inputting the jog signal
(jog operation) or RT signal (second function selection) during an inverter stop will switch to
the normal operation and give priority to jog operation or second function selection. Note
that JOG and RT signal input is invalid even if JOG signal and RT signal are input during
operation in automatic acceleration/deceleration mode.
Since acceleration/deceleration is made with the stall prevention operation being activated,
the acceleration/deceleration speed always varies according to the load conditions.
Note that when proper values are set in Pr. 7 and Pr. 8, acceleration/deceleration time may
be shorter than selecting shortest acceleration/deceleration mode.
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