Edwards nEXT200200 - Electrical Supply Failure

6.7.4 Electrical supply failure
WARNING: POWER SUPPLY FAILURE
Risk of injur
y. If the power supply fails when the pump is in operaon, the rotor can
spin for approximately 30 minutes. The control circuit can possibly not give indicaon
that the rotor is spinning.
WARNING: AUTOMATIC RESTART
Risk of injury. If the parallel start control signal on the logic interface connector is set
to start, the pump can automacally restart when the electrical supply is restored
aer an electrical supply failure. Make sure that people does get injured by the
rotang blades of the pump.
If the electrical supply to the pump fails when the pump is rotang, the motor of the
pump is used as a generator.
The regenerated power is used to:
▪ keep the output signals on the logic interface (such as the normal signal and serial
communicaons)
▪ to power the three indicator LEDs on the motor controller
▪ to keep the power at the motor controller outputs (to control the vent valve, if
installed).
As the rotaonal speed of the pump decreases, the power generated from the motor
also decreases unl it is no longer able to keep power to the logic interface or LEDs. This
will occur at speeds less than 50% full rotaonal speed. There will be no indicaon of
pump rotaonal speed, but the impeller can possibly connue to operate.
When the power is restored aer a power failure, the behavior of the pump depends on
the control mode at the me of failure (parallel or serial) and the duraon of me the
pump was without power. Refer to Table: Behaviour of a pump when the power is re-
instated aer an electrical supply failure on page 71 for number of scenarios.
Table 21 Behaviour of a pump when the power is re-instated aer an electrical supply failure
Length of power failure Control mode Behaviour of pump
Power is restored before the
rotaonal speed of the pump
decreases below 50%
Parallel or serial control mode
Regenerave power keeps all
output signals acve during the
power failure. The pump will
speed up to designated speed
aer the power has been
restored.
Page 71
B85200880_D - Oper
aon