Hitachi SJ300-037HFE 사용자 설명서
SJ300 Inverter
Oper
ati
ons
ons
and Monitor
ing
4–35
Overload
Restriction
Restriction
The inverter constantly monitors the motor current during acceleration, deceleration, and
constant speed. If the inverter reaches the overload restriction level, it adjusts the output
frequency automatically to limit the amount of overload. This function prevents an over-current
trip by inertia during rapid acceleration or large changes in load at constant speed. It also
attempts to prevent an over-voltage trip on deceleration due to regeneration. It accomplishes
this by temporarily suspending deceleration and/or increasing the frequency in order to dissi-
pate regenerative energy. Once the DC bus voltage falls sufficiently, deceleration will resume.
constant speed. If the inverter reaches the overload restriction level, it adjusts the output
frequency automatically to limit the amount of overload. This function prevents an over-current
trip by inertia during rapid acceleration or large changes in load at constant speed. It also
attempts to prevent an over-voltage trip on deceleration due to regeneration. It accomplishes
this by temporarily suspending deceleration and/or increasing the frequency in order to dissi-
pate regenerative energy. Once the DC bus voltage falls sufficiently, deceleration will resume.
OLR Parameter Selection – Two sets of overload restriction parameter settings and values are
available as outlined in the table below. Use the B021—B026 group of settings to configure the
two set of parameters as needed. By assigning the Overload Restriction function [OLR] to an
intelligent terminal, you can select the set of restriction parameters that is in effect.
available as outlined in the table below. Use the B021—B026 group of settings to configure the
two set of parameters as needed. By assigning the Overload Restriction function [OLR] to an
intelligent terminal, you can select the set of restriction parameters that is in effect.
Function
Function Code
Data or Range
Description
Set 1
Set 2
Overload Restriction
Operation Mode
Operation Mode
B021
B024
00
Disable
01
Enabled during accel
and constant speed
and constant speed
02
Enabled during constant
speed
speed
03
Enabled during accel,
constant speed, and
decel
constant speed, and
decel
Overload Restriction
Setting
Setting
B022
B025
Rated current * 0.5
to rated current * 2
to rated current * 2
Current value at which
the restriction begins
the restriction begins
Deceleration Rate at
Overload Restriction
Overload Restriction
B023
B026
0.1 to 30 seconds
Deceleration time when
overload restriction
operates
overload restriction
operates
Opt.
Code
Symbol
Function Name
Input
State
Description
39
OLR
Overload Restric-
tion Selection
tion Selection
ON
Selects Overload Restriction Set 2,
B024, B025, B026 settings in effect
B024, B025, B026 settings in effect
OFF
Selects Overload Restriction Set 1,
B021, B022, B023 settings in effect
B021, B022, B023 settings in effect
Valid for inputs:
C001, C002, C003, C004,
C005, C006, C007, C008
C005, C006, C007, C008
Required
settings:
settings:
B021, B022, B023 (Mode 1),
B024, B025, B026 (Mode 2)
B024, B025, B026 (Mode 2)
Notes:
• If the overload restriction constant (B023 or
• If the overload restriction constant (B023 or
B026) is set too short, an over-voltage trip
during deceleration will occur due to regener-
ative energy from the motor.
during deceleration will occur due to regener-
ative energy from the motor.
• When an overload restriction occurs during
acceleration, the motor will take longer to
reach the target frequency, or may not reach
it. The inverter will make the following
adjustments:
a) Increase the acceleration time
b) Raise torque boost
c) Raise overload restriction level
reach the target frequency, or may not reach
it. The inverter will make the following
adjustments:
a) Increase the acceleration time
b) Raise torque boost
c) Raise overload restriction level
5
3
1
7
6
4
2
8
FW
TH
PLC
CM1
P24
CM1
See I/O specs on page
. Jumper position shown is
for –xFU/-xFR models; for –xFE models,
see page
see page
.)
OLR