N3 High Slip Braking - YASKAWA E7U Programming Manual

n3 High Slip Braking

High slip braking (HSB) is a method of decreasing the stopping time of a load without using dynamic braking. The regenerated
energy of the decelerating load is dissipated in the motor windings through increased motor slipping. Because of the increased
temperature of the motor windings, there is a limitation on the occurrence of HSB usage (~5% duty cycle). The stopping time
using HSB is approximately 50% of what can be done with the standard braking methods. HSB can be activated by closing a
digital input configured as a High Slip Braking input (H1-0x=68). The HSB digital input has priority over an active Run input
and will be implemented immediately. HSB is only applied to stopping the motor and load and cannot be used for changing
speeds. HSB can only be activated when the output frequency is greater than 6 Hz. When a HSB command is given it is not
possible to restart the Drive until the motor is stopped and the Run command is cycled.
IMPORTANT
n3-01 High-Slip Braking Deceleration Frequency Width
Setting Range: 1 to 20% of maximum frequency
Factory Default: 5% of maximum frequency
Parameter n3-01 sets the amount of frequency reduction that will be applied in order to create the increase motor slip condition
and lower the DC Bus voltage. Normally this parameter will not need to be adjusted from the factory default. If the OV fault
occurs during HSB increase n3-01 in small increments (~2% per adjustment). n3-01 is set as a percentage of the maximum
frequency (E1-04).
n3-02 High-Slip Braking Current Limit
Setting Range: 100 to 200% of Drive rated output current
Factory Default: 150% of Drive rated output current
Parameter n3-02 sets the maximum current to be output during an HSB stop. The higher n3-02 is set the shorter the motor
stopping time will be but the greater the motor winding heating will be. Increasing the setting of n3-02 should only be done in
small increments. Parameter n3-02 is set as a percentage of motor rated current (E2-01).
n3-03 High-Slip Braking Dwell Time at Stop
Setting Range: 0.0 to 10.0 Seconds
Factory Default: 1.0 Seconds
At the end of a HSB action the Drive will hold the frequency reference at the minimum frequency (E1-09) for a period of time
configured by parameter n3-03. If n3-03 is set too short there may be residual motion of the motor shaft after the HSB braking
has completed and the Drive output is shut off. The residual motion can be caused by machine/load inertia.
It is very important that Auto-tuning is performed before High Slip Braking is attempted. The Drive should be
Auto-tuned again if the motor or cable length is changed since the last Auto-tuning.
Programming 118