YASKAWA CR700, Technical Manual, Page: 753 / 886

Parameter
Details
11
11.9 L: Protection Function
YASKAWA SIEPC71061723A YASKAWA AC Drive CR700 Technical Manual 753
Stall Prevention during deceleration controls the deceleration as specified by the DC bus voltage and does not let
high inertia or fast deceleration cause ov [Overvoltage] faults.
0 : Disabled
The drive decelerates as specified by the deceleration time. If the deceleration time is too short, the drive can
detect an ov fault.
Note:
If an ov fault occurs, connect a dynamic braking option to the drive. If an ov fault occurs while operating the drive with a dynamic
braking option and A1-02 = 0 or 2 [Control Method Selection = V/f Control, Open Loop Vector] and L3-04 = 0 , set L3-04 = 3 .
1 : General Purpose
The drive decelerates as specified by the deceleration time. When the DC bus voltage is more than the Stall
Prevention level during deceleration, the drive stops deceleration and continues operation at the current frequency.
The drive resumes deceleration at the set deceleration time once the DC bus voltage drops below the stall
prevention level. Frequent use of Stall Prevention will help prevent ov faults when the deceleration time is set
shorter than the drive can usually accept.
Note:
The Stall Prevention during Deceleration function will increase the deceleration time to stop and the deceleration time will be longer
than the setting. This function is not applicable for applications such as conveyors, where the precision of the stop position is very
important. Consider using a dynamic braking option instead in such applications.
The DC bus voltage level for Stall Prevention depends on the input voltage setting of E1-01 [Input AC Supply
Voltage]
.
Table 11.34 Stall Prevention Level during Deceleration
Drive Input Voltage Stall Prevention Level during Deceleration
200 V class 377 V
400 V class 754 V
This figure shows the Stall Prevention during Deceleration function.
Figure 11.92 Stall Prevention Operation during Deceleration
2 : Intelligent (Ignore Decel Ramp)
The drive adjusts the deceleration rate to keep the DC bus voltage is kept at the level set to
L3-17 [DC Bus
Regulation Level]
. This makes the shortest possible deceleration time and will not let the motor stall. The drive
ignores the selected deceleration time and the possible deceleration time cannot be less than 1/10 of the set
deceleration time.
This function uses these parameters to adjust the deceleration rate:
• L3-20 [DC Bus Voltage Adjustment Gain]
• L3-21 [OVSuppression Accel/Decel P Gain]
• L3-24 [Motor Accel Time @ Rated Torque]
• L3-25 [Load Inertia Ratio]
Note:
The deceleration time is not constant. For applications where the precision of the stop position is very important, use a dynamic braking
option and do not change the setting from L3-04 = 0 . If an ov occurs, set L3-04 = 3 .
3 : General Purpose w/ DB resistor
A braking resistor is necessary for this setting. The braking resistor and the drive work together for the Stall
Prevention during Deceleration function.
4 : Overexcitation/High Flux
Enables Overexcitation/High Flux 1. Enables a shorter deceleration time than when L3-04 = 0 .