gefran VDI100 Series Instruction Manual page 233

The hold function is used to temporarily hold the reference frequency in order to prevent stalling the motor or
preventing an over current condition during starting or stopping due to load conditions.
During start the inverter will operate at the hold frequency at start for the time specified in the parameter 11-44
in order to establish the magnetic flux.
Note:
The acceleration of deceleration time does not include the start and stop hold time. Refer to the figure 4.4.94.
When the inverter is in stop mode, this function can also be used to prevent wind milling. In addition, it can be
used for the purpose of braking using the motor to consume the braking energy resulting in a better controlled
stop. Refer to the DC brake parameter 07-16 for DC braking during start.
Notes:
- The hold function at start is inactive when the hold frequency at start (11-43) is set to a value less than Fmin
(01-08).
- The hold function at stop is inactive when the hold frequency at stop (11-45) is set to a value less than Fmin
(01-08).
Code Parameter Name / Range
11-47 KEB Deceleration time
0.0~25.5 s
11-48 KEB detection level
230V:190~210 V
400V:380~420 V
KEB function can be used to keep the inverter from tripping on a under voltage condition due to a momentary
power-loss. To enable the KEB function set parameter 11-47 to a value greater than 0.0 sec.
Upon detection of a power-loss the inverter uses the KEB deceleration time (11-47) to decelerate the motor and
using the regenerative energy from the motor to maintain the DC-bus at a nominal level.
11-48: KEB detection level
If the DC-bus voltage falls below the value set in 11-48, the KEB is activated and the inverter starts decelerat-
ing according to the value set in 11-47.
To accelerate back to the original output frequency one of the digital inputs (03-00 to 03-07) set for 48 (KEB ac-
celeration) has to be activated and the DC voltage has to rise above 11-48 + delta V (Delta V = +10V for 230V
Class, Delta V = +20 V for 400V Class.
Refer to the example in Figure 4.4.95.
VDI100 • Instruction manual
Figure 4.4.94 Reserved function
Output
Frequency
11-44
RUN
command
11-43
11-46
11-45
t
t
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