Omron V1000 User Manual page 205

5.8 L: Protection Functions
Setting 4: Operation with Reduced Speed
If an overheat alarm occurs, the operation is continued but the speed is reduced to the level set in parameter L8-19. If after
10 s the oH alarm is still present, the speed is reduced once more. The amount of reduction depends on how often the alarm
repeats. If the oH alarm disappears while the drive is operating at a reduced speed, then the drive will switch back to the
previous speed it was reduced to before.
digital output programmed for 4D is switched when the oH alarm is still active after ten reduction cycles.
Output frequency
f
ref
f × (L8-19)
ref
f × (L8-19) 2
ref
f × (L8-19)
3
ref
f × (L8-19) 4
ref
oH alarm number
Digital ouput (4D)
n L8-19: Frequency Reduction Rate During Overheat Pre-Alarm
Specifies how much the output frequency is reduced when L8-03 is set to 4 and an oH alarm is present. Set as a factor of
the maximum output frequency.
No.
L8-19 Frequency Reduction Rate During oH Pre-Alarm
n L8-05: Input Phase Loss Protection Selection
Enables or disables the input phase loss detection.
No.
L8-05
<1> Disabled in 200 V single-phase drives.
Setting 0: Disabled
Setting 1: Enabled
Enables the input phase loss detection. As detection is performed by measuring the DC bus ripple, a phase loss fault (PF)
can also be triggered by power supply voltage imbalance or main circuit capacitor deterioration. Detection is disabled
when:
• The drive is decelerating.
• No Run command is active.
• Output current is less than or equal to 30% of the drive rated current.
n L8-07: Output Phase Loss Detection
Enables or disables the output phase loss detection, which is triggered when the output current falls below 5% of the drive
rated current.
Note: Output phase loss detection can mistakenly be triggered if the motor rated current is very small compared to the drive rating. Disable this
parameter in such cases.
No.
L8-07
Setting 0: Disabled
204
Figure 5.88 explains the operation with reduced speed during an oH alarm. A
10 s 10 s
10 s
oH
Alarm
Reset oH
oH
Alarm
oH
Alarm
Figure 5.88 Output Frequency Reduction During Overheat Alarm
Name
Name
Input Phase Loss Detection Selection
Name
Output Phase Loss Detection Selection
10 s 10 s 10 s
Alarm
Reset oH
Alarm
Setting Range
Setting Range
Setting Range
SIEP C710606 20 OYMC AC Drive - V1000 User Manual
10 s
oH
etc.
Alarm
time
Default
0.1 to 0.9 0.8
Default
<1>
0 or 1
1
Default
0 to 2 0