1-32 Functional Description
7000-TD002A-EN-P – September 2007
3. When the phase error between the motor voltage and bypass
voltage has remained less than the value specified by parameter
Sync Error Max (228) for the time interval specified by
parameter Sync Time (229) the drive activates BP CONTACTOR
output on the ACB.
4. After a time delay specified by Sync Off Delay (227) the drive
shuts off. It is important that this parameter is set to the correct
value. This should be at least 1-2 cycles less than the contactor
closing time. If this time delay is set too short, the motor voltage
could drift out of phase with the bypass voltage. If the time delay
is set too long, a drive overcurrent fault may occur because the
drive is unable to control its output voltage and frequency once
the bypass contactor has closed.
A T T E N T I O NA T T E N T I O N
If parameter Sync Off Delay is set incorrectly,
damage may occur to the drive, motor,
couplings, and driven load if a transfer to
bypass is attempted.
5. When the BP CONTACTOR STATUS input indicates that the
bypass contactor has closed, the drive deactivates the OP
CONTACTOR output. When the output contactor opens, the
drive is disconnected from the motor, leaving the output filter
capacitors charged to bypass voltage.
6. The synchronous transfer is now complete and the motor is
running on bypass.
7. If in (3), the drive is unable to synchronize within the time
specified by parameter Sync Xfer Time (230) the synchronous
transfer is aborted. At this point the drive can either fault or issue
a warning. This is controlled by the parameter Drive Fault4
(370). If the bit SyncXferFail is set to 1, then the drive issues a
fault. If the bit is set to 0, then a warning is issued.
Synchronous Transfer
cont.
To Next Page
Loading...
Need help?
General
