User Manual Instruction Manual

Application Notes 13-89
If the drive is in a “run permit” state, the reconnect algorithm is run to match the speed
of the motor. The drive then accelerates at the programmed rate to the set speed.
480 example shown. See Table 13-7 for further information.
13.34.5 Decel
This mode of operation is useful if the mechanical load is high inertia and low friction.
By recapturing the mechanical energy, converting it to electrical energy and returning
it to the drive, the bus voltage is maintained. As long as there is mechanical energy,
the ride through time is extended and the motor remains fully fluxed up. If AC input
power is restored, the drive can ramp the motor to the correct speed without the need
for reconnecting.
The drive determines a power loss has occurred if the bus voltage drops below
Vtrigger.
If the drive is running, the inertia ride through function is activated.
The load is decelerated at just the correct rate so that the energy absorbed from the
mechanical load balances the losses and bus voltage is regulated to the value
Vinertia.
The Power Loss alarm in Drive Alarm 1 (211) is set and the power loss timer starts.
The Alarm bit in Drive Status 1 (209) is set if the Power Loss bit in Alarm Config 1(259)
is set.
The drive faults with a F003 – Power Loss fault if the power loss timer exceeds Power
Loss Time (189) and the Power Loss bit in Fault Config 1 (238) is set.
The drive faults with a F004 – UnderVoltage fault if the bus voltage falls below Vmin
and the UnderVoltage bit in Fault Config 1 (238) is set.
The inverter output is disabled and the motor coasts if the output frequency drops to
zero or if the bus voltage drops below Vopen or if any of the “run permit” inputs are
de-energized.
The pre-charge relay opens if the bus voltage drops below Vopen.
680V
620V
560V
500V
305V
407V
Bus Voltage
Motor Speed
Output Enable
Power Loss
Drive Fault
Pre-Charge