Over-Current Trip Suppression: B027 - Hitachi WJ200-001S Instruction Manual

Ver.3− − − − 6

Over-current Trip Suppression: b027 -

The Over-current Trip Suppression function monitors the motor
current and actively changes the output frequency profile to
maintain the motor current within the limits. Although "LAD"
refers to "linear acceleration / deceleration", the inverter only
"STOPs" the acceleration and deceleration ramp so that it will not
cause an over-current trip event.
The graph at right shows an inverter output profile that starts
acceleration to a constant speed. At two different points during the
acceleration, motor current increases and exceeds the fixed level of
Over-current Trip Suppression level.
When the Over-current Trip Suppression feature is enabled by b b b b 0 0 0 0 2 2 2 2 7 7 7 7 = 0 0 0 0 1 1 1 1 /0 0 0 0 2 2 2 2 , the inverter stops the
acceleration ramp in each case until the motor current level is again less than the threshold value, which
is approximately 180% of the rated current of the inverter.
When using the Over-current Trip Suppression feature, please note the following:
When the feature is enabled (b b b b 0 0 0 0 2 2 2 2 7 7 7 7 = 0 0 0 0 1 1 1 1 /0 0 0 0 2 2 2 2 ), the actual acceleration may be longer than the value
•
set by parameters F F F F 00
The Over-current Trip Suppression feature does not operate by maintaining a constant motor
•
current, so it does not prevent Over-current Trip events completely. Over-current trip event may
happen during extreme acceleration or by the short-circuit states for example.
When b b b b 0 0 0 0 2 2 2 2 7 7 7 7 set to "0 0 0 0 2 2 2 2
•
raises the effect by reducing output voltage after an acceleration and deceleration halt. Following
are the related parameters for this function.
002 2 2 2 /F F F F 2 2 2 2 0 0 0 0 2 2 2 2 in some cases.
00 00
Enable with voltage reduction", the Over-current Trip Suppression function
...
Func. Func.
Func. Func.
Name Name Name Name
Code Code
Code Code
b b b b 0 0 0 0 2 2 2 2 7 7 7 7 OC suppression selection
=
B027 B027 B027 B027
Motor
0
Output
0
Description Descrip Descrip Descrip tion tion tion
00 00 00...Disabled 00
0 0 0 0 1 1 1 1 ...Enabled without voltage
reduction
0 0 0 0 2 2 2 2 ...Enable with voltage
reduction
(Added by Ver.3.0)
/
01 01 01 01 02 02 02 02
OC LAD STOP = Enabled
Approx. 150% of the inverter
rated current
Stops accel
Resumes accel
Set acc time (F002 F002)
F002 F002
Actual acc time
t
t