4-2 Function Mode •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. 4 •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. Functions *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. (Example 1) (Example 2) Main circuit DC voltage at power recovery Main circuit P-N voltage Vpn (V) Main circuit P-N voltage Vpn (V) b052 b051 b052 b051 Output frequency (Hz) Time Output frequency (Hz) Time b050 = 02, 03 (Deceleration stop) Time Time Power recovery Power recovery Note: The main circuit DC voltage level, while the function is running, may fall below the b052 set value depending on the proportional gain and integral time settings.
4-62 b050 b051 Operation 02 (without recovery) b052 > Main circuit DC voltage at power recovery Deceleration stop (DC voltage constant control) (example 1) b052 Deceleration stop (normal operation) (example 2) 03 (with recovery) b052 > Main circuit DC voltage at power recovery Deceleration stop (DC voltage constant control) (example 1) b052 Operation (normal operation) (example 2) Power recovery Main circuit DC voltage DC voltage kept constan t DC voltage kept constan t b050 = 03 (Operation) b050 = 02 (Deceleration stop)