6.7.4 Electrical supply failure
WARNING: POWER SUPPLY FAILURE
Risk of injury. If the power supply fails when the pump is in operation, the rotor can
spin for approximately 30 minutes. The control circuit can possibly not give indication
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 automatically restart when the electrical supply is restored
after an electrical supply failure. Make sure that people does get injured by the
rotating blades of the pump.
If the electrical supply to the pump fails when the pump is rotating, 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
communications)
▪
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 rotational speed of the pump decreases, the power generated from the motor
also decreases until it is no longer able to keep power to the logic interface or LEDs. This
will occur at speeds less than 50% full rotational speed. There will be no indication of
pump rotational speed, but the impeller can possibly continue to operate.
When the power is restored after a power failure, the behavior of the pump depends on
the control mode at the time of failure (parallel or serial) and the duration of time the
pump was without power. Refer to
Table: Behaviour of a pump when the power is re-
instated after an electrical supply failure on page 71
for number of scenarios.
Table 21
Behaviour of a pump when the power is re-instated after an electrical supply failure
Length of power failure
Control mode
Behaviour of pump
Power is restored before the
rotational speed of the pump
decreases below 50%
Parallel or serial control mode
Regenerative power keeps all
output signals active during the
power failure. The pump will
speed up to designated speed
after the power has been
restored.
Page 71
B85200880_D - Operation
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