N3: Highslip/Overexcitation Brake - Omron Q2A Series Technical Manual

12.9 n: SPECIAL
• If the drive detects ov [Overvoltage] when acceleration stops under high-inertia loads, increase the setting value
in 50 ms increments.
If the drive detects ov when the load changes suddenly, increase the setting value in 50 ms increments.
• To increase the responsiveness of torque and speed, decrease the setting value in 10 ms increments and examine
the response.
Note:
• Set n2-02 ≤ n2-03 [AFR Time 1 ≤ AFR Time 1]. If n2-02 > n2-03, the drive will detect oPE08 [Parameter Selection Error].
• When you change the value in n2-03, also change the value in C4-06 [M2 Trq Comp Delay Time] by the same ratio.
◆

n3: HIGHSLIP/OVEREXCITATION BRAKE

n3 parameters configure High Slip Braking and Overexcitation Deceleration.
■
High Slip Braking
High slip braking quickly decelerates motors without braking resistors.
This lets you stop a motor more quickly than with the ramp to stop processes. This function is best for
applications that do not frequently stop the motor, for example the fast stop function for high-inertia loads.
Braking starts when the MFDI for H1-xx = 32 [HiSlipBraking] activates.
An induction motor is necessary to use high slip braking.
Set A1-02 [Control Method] to one of these values to enable high slip braking:
• 0 [V/f Control]
• 1 [PG V/f Control]
Principles of Operation
HSB increases motor slip by significantly decreasing the frequency supplied to the motor at the same time that
deceleration starts. A large quantity of current flows through the motor to increase the motor loss, and the motor
decelerates while the motor windings consume the regenerative energy.
The drive keeps the motor current at a constant level during deceleration to prevent overvoltage and do automatic
braking and it also keeps a slip level that causes the maximum quantity of deceleration torque.
High Slip Braking Precautions
• Do not use the high slip braking function in these applications:
– Frequent deceleration
– Deceleration time differences
– Continuous regenerative loads
– It is necessary to accelerate again during deceleration
• Motor loss increases during high slip braking. 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.
• The drive ignores the configured deceleration time during high slip braking. To stop motors in the configured
deceleration time, set L3-04 = 1 [StallP@Decel Enable = Enabled] and L3-50 = 3 [StallP@Decel Mode =
HiFlux Overexcitation].
• 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].
786
Figure 12.140 High Slip Braking Time Chart
SIEPYEUOQ2A01A AC Drive Q2A Technical Manual