YASKAWA CIPR-GA50C series Technical Manual page 713

• The drive ignores the configured deceleration time during high slip braking. To stop motors in the configured
deceleration time, set L3-04 = 4 [Stall Prevention during Decel = Overexcitation/High Flux].
• You cannot use high slip braking to decelerate deceleration at user-defined speeds. To decelerate at user-defined
speeds, use the overexcitation deceleration function.
• You cannot accelerate the motor again during high slip braking until you fully stop the motor and input the Run
command again.
• You cannot use high slip braking and the KEB Ride-Thru function at the same time. If you enable those two
functions, the drive will detect oPE03 [Multi-Function Input Setting Err].
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Overexcitation Deceleration
Overexcitation deceleration quickly decelerates motors without braking resistors.
This lets you stop a motor more quickly than with the ramp to stop processes.
Overexcitation deceleration increases excitation current during deceleration to cause a large quantity of braking
torque through motor overexcitation.
You can set the deceleration speed to adjust the deceleration time for overexcitation deceleration. Overexcitation
deceleration lets you accelerate the motor again during deceleration. Enter the Run command during
overexcitation deceleration to cancel overexcitation deceleration and accelerate the drive to the specified speed.
To enable this function, set L3-04 = 4, 5 [Stall Prevention during Decel = Overexcitation/High Flux,
Overexcitation/High Flux 2].
When L3-04 = 4, the motor will decelerate for the Deceleration Times [C1-02, C1-04, C1-06, or C1-08]. If the
drive detects ov [Overvoltage], increase the deceleration time.
When L3-04 = 5, the drive uses the value in C1-02, C1-04, C1-06, or C1-08 to decelerate and it adjusts the
deceleration rate to keep the DC bus voltage at the level set in L3-17 [DC Bus Regulation Level]. The load inertia
and motor characteristics have an effect on the braking time.
Notes on Overexcitation Deceleration
• Do not use Overexcitation Deceleration with a braking resistor.
• Do not use Overexcitation Deceleration for these applications. Connect a braking resistor to the drive as an
alternative to Overexcitation Deceleration.
– Frequent sudden decelerations
– Continuous regenerative loads
– Low inertia machines
– Machines that have no tolerance for torque ripples
• Motor loss increases during overexcitation deceleration. Use this function when the duty time factor is 5% ED
or less and the braking time is 90 seconds or less. The load inertia and motor characteristics have an effect on
the braking time.
• You can use overexcitation deceleration in OLV control, but this control method decreases the precision of
torque control and braking efficiency. Use V/f control for the best results.
• The drive disables these functions during braking with Overexcitation Deceleration 2:
– Hunting Prevention Function (V/f Control)
– Torque Limit Speed Control (OLV Control)
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n3-01: HSB Deceleration Frequency Width
No.
Name
(Hex.)
n3-01 HSB Deceleration
Frequency Width
(0588)
Expert
When you must detect ov [DC Bus Overvoltage] during high-slip braking, set this parameter to a large value.
YASKAWA SIEPC71061753A GA500 Technical Manual
V/f OLV OLV/PM AOLV/PM EZOLV OLV/PM
Sets the amount by which the output frequency is to be lowered during high-slip braking, as a
percentage of E1-04 [Maximum Output Frequency], which represents the 100% value.
12.10 n: Special Adjustment
Description
Default
(Range)
5%
(1 - 20%)
12
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