Program features 123
Implementing the undervoltage control (power loss ride-through)
Implement the undervoltage control function as follows:
• Check that the undervoltage control function of the drive is enabled with
parameter 30.31 Undervoltage control.
• Parameter 21.01 Vector start mode must be set to Automatic (in vector mode) or
parameter 21.19 Scalar start mode to Automatic (in scalar mode) to make flying
start (starting into a rotating motor) possible.
If the installation is equipped with a main contactor, prevent its tripping at the input
power break. For example, use a time delay relay (hold) in the contactor control
circuit.
WARNING! Make sure that the flying restart of the motor will not cause any
danger. If you are in doubt, do not implement the undervoltage control function.
Automatic restart
It is possible to restart the drive automatically after a short (max. 5 seconds) power
supply failure by using the Automatic restart function, provided that the drive is
allowed to run for 5 seconds without the cooling fans operating.
When enabled, the function takes the following actions upon a supply failure to a
successful restart:
• The undervoltage fault is suppressed (but a warning is generated).
• Modulation and cooling is stopped to conserve any remaining energy.
• DC circuit pre-charging is enabled.
If the DC voltage is restored before the expiration of the period defined by parameter
21.18 Auto restart time and the start signal is still on, normal operation will continue.
However, if the DC voltage remains too low at that point, the drive trips on a fault,
3220 DC link undervoltage.
WARNING! Before you activate the function, make sure that no dangerous
situations can occur. The function restarts the drive automatically and
continues operation after a supply break.
Voltage control and trip limits
The control and trip limits of the intermediate DC voltage regulator are relative to the
supply voltage as well as drive/inverter type. The DC voltage (U
DC
) is approximately
1.35 times the line-to-line supply voltage, and is displayed by parameter 01.11 DC
voltage.
ACS580 FW.book Page 123 Wednesday, September 21, 2016 9:48 PM
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