Preventing Overvoltage During Deceleration (Stall Prevention During Deceleration Function) - YASKAWA Varispeed G7 Instruction Manual

Preventing Overvoltage During Deceleration (Stall Prevention During
Deceleration Function)
The Stall Prevention During Deceleration function makes the rate of deceleration more gentle to suppress
increases in DC bus voltage when the DC bus voltage exceeds the set value during motor deceleration.
This function automatically lengthens the deceleration time with respect to the bus voltage, even if the decel-
eration time has been set to a considerably small value.
If L3-04 is set to 1 or 2, when the main circuit DC voltage approaches the stall prevention level during decel-
eration, deceleration stops, and when deceleration falls below the level, is restarted. Using this operation,
deceleration time is automatically lengthened. If L3-04 is set to 1, deceleration time returns to the set value,
and if L3-04 is set to 2, deceleration is automatically adjusted to a faster deceleration time within the range of
the stall prevention level during deceleration.
Related Constants
Name
Con-
stant
Display
Number
Stall preven- 0: Disabled (Deceleration as set.
tion selection
during decel
1: Enabled (Deceleration is
2: Intelligent deceleration mode
L3-04
StallP Decel Sel
3: Enabled (with Braking
When a braking option (Braking
Resistor, Braking Resistor Unit,
Braking Unit) is used, always set
to 0 or 3.
* The setting range for flux vector and open-loop vector 2 controls is 0 to 2.
Setting
Description
Range
If deceleration time is too
short, a main circuit
overvoltage may result.)
stopped when the main circuit
voltage exceeds the
overvoltage level.
Deceleration restarts when
voltage is returned.)
(Deceleration rate is
0 to 3
automatically adjusted so that
the Inverter can decelerate in
the shortest possible time. Set
deceleration time is
disregarded.)
Resistor Unit)
Acceleration and Deceleration Characteristics
Control Methods
Change
Open
Factory during
V/f
Loop
Setting Opera-
V/f with
Vector
tion
PG
*
1 No Q Q
MEMO
Open
BUS
Flux
Loop
Regis-
Vec-
Vector
ter
tor
1 2
Q Q Q 492H
6-
25