Omron SYSDRIVE RX Series User Manual page 171

Momentary Power Interruption Non-stop DC Voltage Constant Control
(b050 = 02: without recovery, b050 = 03: with recovery)
•If a momentary power interruption or main circuit DC voltage drop occurs during operation, the
Inverter decelerates while keeping the main circuit DC voltage at the value set in momentary power
interruption non-stop target voltage (OV-LADSTOP level) b052.
•This function is started when the following conditions are all satisfied:
• b050 = "02" or "03"
• The Inverter is running. (This function is disabled during trip/undervoltage/stop.)
• The control power supply is momentarily interrupted, or the main circuit DC voltage falls below
the momentary power interruption non-stop function starting voltage (b051)
•This function is enabled when the above starting conditions are satisfied, even if the J51 connector
cable is disconnected from terminals Ro and To and is connected from main terminal P to Ro and
from N and To, or even if the control power supply is separated from the main circuit power supply.
•If the time of momentary power interruption is short, the Inverter can continue to run without
shutting off the output. However, if undervoltage occurs because of momentary power interruption,
the Inverter immediately shuts off the output, and stops operating this function. The subsequent
power recovery depends on the setting of retry selection b001.
•With b050 = 03, the Inverter can be restored to normal operation, if a momentary power interruption
occurs and incoming voltage recovers before the output is shut off. Note that the Inverter may
decelerate to a stop, depending on the b051 setting. Below are the details.
b050
b052 > Main circuit DC voltage at
power recovery
02 (without recovery)
b052 < Main circuit DC voltage at
power recovery
b052 > Main circuit DC voltage at
power recovery
03 (with recovery)
b052 < Main circuit DC voltage at
power recovery
•If operation of this function results in deceleration stop, the Inverter is forced to stop, even if the
FW command is ON. To restart the Inverter, make sure that the incoming voltage has recovered,
and input the FW command again.
*4. Make sure that the b051/b052 set values are larger than the undervoltage level (200-V class:
210 V, 400-V class: 410 V). If undervoltage occurs, this function is disabled.
Make sure that b051 is smaller than b052. If the proportional gain setting (b055) is excessively
increased when the difference between b051 and b052 is large, the Inverter may accelerate
immediately after this function starts, resulting in overcurrent.
*5. When b050 = 02, 03, PI control works to keep the internal DC voltage constant.
• Though quicker response is expected with a larger proportional gain (b055), control tends to
be divergent and may easily lead to a trip.
• Response also becomes quicker with a shorter integral time (b056), but if too short, the same
situation may occur.
• If the proportional gain (b055) is too small, the voltage drops immediately after this function
starts, resulting in an undervoltage trip.
b051
Deceleration stop (DC voltage constant control)
(example 1)
Deceleration stop (normal operation) (example 2)
Deceleration stop (DC voltage constant control)
(example 1)
Operation (normal operation) (example 2)
4-2 Function Mode
Operation
4-62
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