Mitsubishi Electric FR-E700 Instruction Manual page 234

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/deceleration in 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/deceleration
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 speed operation.
● 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.
NOTES 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 nor-
mal 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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Parameter