Yaskawa AC Drive Z1000 AC Drive HVAC Fan User Manual
Page 107
Output Frequency
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
Time
specified deceleration time
Figure 1.64 Stall Prevention During Deceleration
Setting 2: Intelligent Stall Prevention
The drive adjusts the deceleration rate so the DC bus voltage is kept at the level set to parameter L3-17. This produces the
shortest possible deceleration time while protecting the motor from stalling. The selected deceleration time is disregarded and
the achievable deceleration time cannot be smaller than 1/10 of the set deceleration time.
This function uses the following parameters for adjusting the deceleration rate:
• DC bus voltage gain (L3-20)
• Deceleration rate calculations gain (L3-21)
• Inertia calculations for motor acceleration time (L3-24)
• Load inertia ratio (L3-25)
Note:
The deceleration time is not constant. Do not use Intelligent Stall Prevention in applications where stopping accuracy is a concern.
Setting 4: Overexcitation Deceleration 1
Overexcitation Deceleration 1 (increasing the motor flux) is faster than deceleration with no Stall Prevention (L3-04 = 0).
Setting 4 changes the selected decel time and functions to provide protection from an overvoltage trip.
Deceleration (Induction Motors) on page 124
for details.
Setting 5: Overexcitation Deceleration 2
Overexcitation Deceleration 2 slows down the motor while trying to maintain the DC bus voltage at the level set to parameter
L3-17. This function shortens the achievable deceleration time more than by using Overexcitation Deceleration 1. Setting 5
will shorten/lengthen the decel time to maintain the L3-17 bus level.
Refer to Overexcitation Deceleration (Induction
n
L3-05: Stall Prevention Selection during Run
Determines how Stall Prevention works during Run. Stall Prevention during run prevents the motor from stalling by
automatically reducing the speed when a transient overload occurs while the motor is running at constant speed.
No.
Name
Setting Range
Default
L3-05
Stall Prevention Selection During Run
0 to 2
1
Note:
Stall Prevention during run is disabled when the output frequency is 6 Hz or lower regardless of the L3-05 and L3-06 settings.
Setting 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 or oL fault.
Setting 1: Decelerate Using C1-02
If the current exceeds the Stall Prevention level set in parameter L3-06, the drive will decelerate at decel time 1 (C1-02). When
the current level drops below the value of L3-06 minus 2% for 100 ms, the drive accelerates back to the frequency reference
at the active acceleration time.
Setting 2: Decelerate Using C1-04
Same as setting 1 except the drive decelerates at decel time 2 (C1-04).
n
L3-06: Stall Prevention Level during Run
Sets the current level to trigger Stall Prevention during run. Depending on the setting of parameter L3-23, the level is
automatically reduced in the constant power range (speed beyond base speed).
The Stall Prevention level can be adjusted using an analog input.
Refer to Multi-Function Analog Input Terminal Settings
1.8 L: Protection Functions
YASKAWA ELECTRIC SIEP YAIZ1U 03A YASKAWA AC Drive – Z1000 Programming Manual
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Parameter Details