
83
14. Protective function ■
◆Speed search function
Description:The speed search function finds the actual speed of motor that is Rotational using inertia, and
then starts smoothly from that speed. When restoring power after a temporary power loss or Rotational using
inertia fan is enable. There are two ways of speed search by set Cd28.
Cd28= 0, invalid
= 1, valid, MCK feedback (above 3HP)
= 2, valid, current detection
= 3, valid, MCK disconnection start+ inertia start
■ Cd28=1
MCK feedback speed search: search motor rotoring speed by MCK feedback signal, then start operation by
the speed.
Constant
No.
Constant name
Settable range
Factory setting
Change during
operation
Cd28
Speed search selection
0 3
0
X
Cd76
Speed search operating current
0 200%
120%
X
Cd77
Speed search deceleration time
0.1 10.0
2.0S
X
Cd78
Speed search waiting time
0.0 20.0
0.2S
X
Operation
command
Output
frequency
Frequency command
Start by frequency detection
Output
voltage
Voltage recovered time
0.3sec
Cd78