11.9 L: Protection Function
754 YASKAWA SIEPC71061723A YASKAWA AC Drive CR700 Technical Manual
Note:
• If you decelerate frequently and the overexcitation time is long, the drive can detect oL1 [Motor Overload] faults. If the drive detects
oL1, decrease the deceleration time or install a braking resistor to the drive.
• The deceleration time during Overexcitation Deceleration changes when the motor characteristics and machine inertia change. Adjust
the n3-13 [OverexcitationBraking (OEB) Gain] and n3-23 [Overexcitation Braking Operation] levels. Refer to “n3: Overexcite
Braking” for more information.
5 : Overexcitation/High Flux 2
Enables Overexcitation/High Flux 2. This function decreases the possible deceleration time more than
Overexcitation/High Flux.
The drive decreases motor speed and tries to keep the DC bus voltage at the L3-17 level.
If the drive detects oL1, decrease the values set in n3-13 and n3-21. If the drive detects ov, increase the value set
in C1-02, C1-04, C1-06, and C1-08 [Deceleration Times].
Note:
• During Overexcitation/High Flux 2, the drive disables Hunting Prevention in V/f Control and also disables Speed Control that uses
torque limit in OLV Control.
• Refer to “n3: Overexcite Braking” for more information.
■ L3-05: Stall Prevention during RUN
No.
(Hex.)
Name Description
Default
(Range)
L3-05
(0493)
Stall Prevention during
RUN
Sets the function to enable and disable Stall Prevention During Run.
1
(0 - 2)
Stall Prevention function during run prevents the motor from stalling by automatically reducing the speed when
an oL1 [Motor Overload] occurs while the motor is running at constant speed.
Note:
The Stall Prevention during Run function is disabled regardless of the setting of L3-05 and L3-06 [Stall Prevent Level during Run] if the
output frequency falls below 6 Hz.
0 : Disabled
Drive runs at the set frequency reference. A heavy load may cause the motor to stall and trip the drive with an oC
[Overcurrent] or oL1.
1 : Deceleration Time 1 (C1-02)
The drive will decelerate for the time set in C1-02 [Deceleration Time 1] .If the current exceeds the Stall
Prevention level set in L3-06. When the current level drops below “L3-06 setting value - 2%” for 100 ms, drive
accelerates again for the acceleration time valid at that time until the set frequency is reached.
2 : Deceleration Time 2 (C1-04)
This setting functions in the same manner as setting 1. If the Stall Prevention function is enabled, the drive
decelerates with the value set in C1-04 [Deceleration Time 2].
■ L3-06: Stall Prevent Level during Run
No.
(Hex.)
Name Description
Default
(Range)
L3-06
(0494)
Stall Prevent Level during
Run
Sets the output current level at which the Stall Prevention function is enabled during run when the
drive rated output current is 100%.
Determined by L8-38
(30 - 150%)
Note:
• This parameter is applicable if L3-05 = 1, 2 [Stall Prevention during RUN = Deceleration Time 1 (C1-02), Deceleration Time 2 (C1-
04)].
• The upper limit of this setting is determined by L8-38 [Carrier Frequency Reduction].
• Depending on the setting of L3-23 [Stall P Reduction at Constant HP] the level is automatically decreased in the constant power range.
Use an Analog Input to Change the Stall Prevent Level during Run
When H3-xx = 8 [MFAI Function Selection = Stall Prevent Level During Run], you can change the stall
prevention level during run through the input gain and bias settings for terminals A1, A2, and A3.
If you set the input level for terminals A1, A2, and A3 [H3-xx = 8] and L3-06, the drive will use the smaller value
for Stall Prevent Level during Run.
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