Overload Limit/Overload Warning - Omron SYSDRIVE MX2 SERIES User Manual

5-9 Functions Relating to Protections, Warnings and Various Output Signals

Overload Limit/Overload Warning

Overload Limit
The Inverter monitors the motor current during acceleration or constant speed operation and
lowers output frequency automatically when the motor current reaches to the overload limit
level.
This function prevents an overcurrent trip caused by excessive moment of inertia during
acceleration, or caused by sporadic load fluctuations during constant speed operation.
You can set 2 types of overload limit functions in b021/b022/b023 and b024/b025/b026.
To switch between b021/b022/b023 and b024/b025/b026, allocate "39: OLR" to a multi-
function input terminal and then turn it ON/OFF.
The overload limit level sets a current value for this function to work.
The overload limit parameter sets a time of deceleration from the maximum frequency to 0 Hz.
When this function operates while the Inverter is accelerating, the acceleration time becomes
longer than the set time.
When the selected control method is sensorless vector control and "03: Enabled during
acceleration/constant speed (accelerated during regeneration)" is selected for b021/b024, the
frequency will increase if current exceeding the overload limit level flows during regeneration
operation.
If the setting of Overload Limit Parameter b023/b026 is too small, an overvoltage trip may
occur because of regenerative energy from the motor even during acceleration. This is due to
automatic deceleration under this function.
Make the following adjustments if this function operates during acceleration and the frequency
doesn't reach the target level.
Increase the acceleration time (refer to "Acceleration/Deceleration Time" on page 5-24).
Increase the overload limit level (b022/b025).
Parameter
No.
b021/b024
b221
b022/b025
b222
b023/b026
b223
C001 to C007
SYSDRIVE MX2 Series USER'S MANUAL (3G3MX2-Axxxx)
Function name
00: Disabled
01: Enabled in acceleration/constant
Overload Limit 1
Selection/
Overload Limit 1
02: Enabled in constant speed
Selection 2
Overload Limit 2
03: Enabled during acceleration/
Selection
Current value at which the overload
limit actuates
Heavy load (b049 = 00):
Overload Limit 1 Level/
0.20 × Rated current to 2.0 × Rated
Overload Limit 1 Level 2
current
Overload Limit 2 Level
Light load (b049 = 01):
0.20 × Rated current to 1.5 × Rated
current
Overload Limit 1 Parameter/ 0.1 to 3000.
Overload Limit 1 Parameter 2 Deceleration time at which the
Overload 2 Limit Parameter overload limit actuates
Multi-function Input 39: OLR (Overload limit switching)
Selection
Data
speed operation
operation
constant speed (accelerated during
regeneration)
5
Default
Unit
setting
−
01
Heavy
load: Rated
current ×
1.50
A
Light load:
Rated
current ×
1.20
1.0 s
− −
5-114