Delta VFD11AMS21AFSHA, User Manual

Page: 229 / 445

Chapter 12 Description of Parameter Settings

MS300 (High Speed Model)
12-06-2
 This function is used for the occasion that the load inertia is unsure. When it stops in normal load,
the over-voltage won’t occur during deceleration and meet the setting of deceleration time.
Sometimes, it may not stop due to over-voltage during decelerating to stop when increasing the
load regenerative inertia. At this moment, the AC motor drive will extend the deceleration time
automatically until the drive stops.
 When Pr. 06-02 is set to 0: During deceleration, the motor will exceed the synchronous speed
due to load inertia. In this case the motor becomes an electric generator. The DC bus voltage
may exceed its maximum allowable value due to motor regeneration in some situation, such as
loading inertia is too high or Decel. Time is set too short. When traditional over-voltage stall
prevention is enabled and the DC voltage detected is too high, the drive will stop decelerating
(output frequency remains unchanged) until the DC voltage drops below the setting value again.
Output
frequency
Deceleration c har acteristic
when Ov er-Voltage Stall
Pr ev ention enabled
F requenc y Held
previous deceleration time
Time
Time
High-voltage
at DC si de
Ov er-v ol tage
detec ti on
level
requir ed time for decelerating to 0Hz when over- voltage
stall prevention is enabled.
 When Pr. 06-02 is set to 1: When use smart over-voltage stall prevention during deceleration, the
drive will maintain DC bus voltage when decelerating and prevent the drive from OV.
Output Frequency
DCBUS Voltage
310Vdc
370Vdc
Time
230V Series
60Hz
0
 When the over-voltage stall prevention is enabled, drive deceleration time will be longer than the
setting.