Preconditions for Down Transfer of Synchronous Motor
The control uses the spinning load algorithm to synchronize the drive to the line connected
motor.
Preconditions for activating spinning load:
• The Spinning Load Enable parameter must be set true.
• The drive must be in the "IDLE" state prior to down transfer.
• The motor is running from the line. The line contactor is closed and the
"Contactor Acknowledge" signal is provided to the drive.
Procedure for Presetting the Internal Field Control Regulator
Refer to Analog Input #4 Menu (4332) in Section Options for Auto Menu (4) in
Chapter Parameter Assignment / Addressing to preset the internal eld control regulator during
transition between sources. This signal is fed back from the PLC as the active eld command
level. Analog Input #4 is dedicated for this function. No other input can be used.
1. Select the correct analog source through the pick list on this parameter. The eld command
from the drive must exit via a programmable analog output.
2. Select the menu item for the desired analog output and select "Synch Motor Field" as the
signal. This signal goes to the PLC as the drive source for the eld command.
3. Set SOP ag EnableAnalog4_O to true and select the Loss of Signal (LOS) action.
8.17.13 Synchronous Transfer for Permanent Magnet Motors (PMM)
NOTICE
Potential Damage to Motor
Line operation for a PMM is not recommended as there is no protection for the motor for pole
slippage.
Use of synchronous transfer with a PMM could result in damage to the motor.
Note
For synchronous transfer of a PMM, the Auto and Auto Phase Advance modes must be disabled.
The Manual modes may be used with caution, but may also prevent proper operation.
Up Transfer of a PMM
With PMMs, up transfers are accomplished by taking the SM up to speed on the drive to match
the frequency and then the phase of the line. This is the same way that up transfer is
accomplished for an IM, by using the drive input line frequency as a velocity reference. However,
with a PMM connected to the line, there is nothing to protect it from pole slip, which can damage
the motor. The drive has a pole slip detection, which will protect the drive. Also, the drive has
limited power as compared to a low impedance line source, so fault currents could be higher.
Advanced Operating Functions
8.17 Synchronous Transfer
NXGPro+ Control Manual
Operating Manual, A5E50491925A 267
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