Hitachi WJ200-001L, Instruction Manual

Page: 515 / 680

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
b0
0 0
02
2 2
27
7 7
7 = 0
0 0
01
1 1
1/0
0 0
02
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 b0 0 0 02 2 2 27 7 7 7 = 0 0 0 01 1 1 1/0 0 0 02 2 2 2), the actual acceleration may be longer than the value
set by parameters F F F F00 00 00 002 2 2 2/F F F F2 2 2 20 0 0 02 2 2 2 in some cases.
•
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 b0 0 0 02 2 2 27 7 7 7 set to "0 0 0 02 2 2 2
…
Enable with voltage reduction", the Over-current Trip Suppression function
raises the effect by reducing output voltage after an acceleration and deceleration halt. Following
are the related parameters for this function.
Func.
Func. Func.
Func.
Code Code Code Code
Name Name Name Name Descrip Descrip Descrip Description tion tion tion
b
b b
b0
0 0
02
2 2
27
7 7
7 OC suppression selection
00 00 00 00
…
Disabled
0 0 0 01 1 1 1
…
Enabled without voltage
reduction
0
0 0
02
2 2
2
…
Enable with voltage
reduction
(Added by Ver.3.0)
Motor
0
t
Output
0
t
Stops accel
Resumes accel
B027 B027 B027 B027 = 01 01 01 01
/
02 02 02 02
OC LAD STOP = Enabled
Set acc time ( F002
F002 F002
F002 )
Actual acc time
Approx. 150% of the inverter
rated current