Bedford B550-2001, Installation And Quick Start Manual, Page: 38 / 116

5-12
Pr.34
Base-Block Time for Speed Search Factory Setting: 0.5 sec
Settings 0.3 to 5.0 sec Unit: 0.1sec
When a momentary power loss is detected, the AC drive will stop its output and will wait
during a specified time interval called Base Block (entered in Pr.34) before resuming
operation. Setting of this parameter should make the residual output voltage due to
regeneration almost zero, before the drive resumes operation.
This parameter also determines the search time when performing external Base-Block
and Fault Reset (Pr.72).
Pr.35
Maximum Current Level for Speed Search Factory Setting: 150
Settings 30 to 200% Unit: 1%
Following a power failure, the AC drive will start its speed search operation only if the
output current is greater than the value determined by Pr.35. When the output current is
less than that of Pr.35, the AC drive output frequency is at a “speed synchronization
point” and will accelerate or decelerate back to the operating frequency at which it was
running prior to the power failure.
Input
Power
Allowable Max. Power Loss Time
Output
Power
Output
Voltage
Pr.33
Speed search starts with
the Master Frequency
Pr.32=1
Baseblock
Time
Pr.34
speed synchronization
detection
speed search
Allowable Max. power loss time
Pr.33
Speed search starts with
minimum output frequency
Pr.32=2
Baseblock
Time
Pr.34
Pr.36
Upper Bound of Output Frequency Factory Setting: 400
Settings 0.10 Hz to 400.0 Hz Unit: 0.1Hz
The Upper/Lower Bounds help prevent operation error and machine damage.
If the Upper Bound of Output Frequency is 50Hz and the Maximum Output Frequency is
60Hz, the Maximum Output Frequency will be limited to 50Hz.
Setting of this parameter must be equal to or greater than the Lower Bound of Output
Frequency (Pr.37).
B550
Series
sensorless vector frequency drive