Edwards nEXT nEXT85 - Protection against Over-Speed; Electrical Supply Failure

below 50% of the full rotaonal speed. Refer to Table: Operang and storage condions
on page 20 for pump operang ranges. Refer to Cooling on page 55 for advice on pump
cooling.
6.8.3 Protecon against over-speed
Control soware in the motor controller controls the pump rotaonal speed and
prevents the operaon of the pump more than its normal full rotaonal speed.
If the control soware fails, the motor controller has a built‑in safety circuit that checks
if the pump is operang at over‑speed. If an over‑speed condion is detected, the motor
controller automacally stops the power to the pump motor and slows the pump to a
stop. The motor controller signals a fail condion if over‑speed is detected.
If the pump is operang at over‑speed, set the pump to o and contact us or the
supplier.
6.8.4 Electrical supply failure
WARNING: POWER SUPPLY FAILURE
Risk of injury. 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 do not get injured by the
rotang blades of the pump.
If the electrical supply to the pump fails when the pump is in operaon, 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)
▪
power the indicator LEDs on the motor controller
▪
keep the power at the motor controller auxiliary outputs (to control the vent valve
or fan, if installed).
When the electronic braking is enabled, the regenerated power is available at the power
supply pins of the logic interface connector (refer to Electronic braking on page 14). This
can be used to power other instruments through short power interrupons. The
minimum voltage of this supply will be 24 V d.c.-20% (19.2 V) provided that the external
load is not excessive and it can be sustained at that minimum voltage when operang
from supply voltages above 48 V d.c. -20% and below 48 V d.c. +5%.
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 rotor can possibly connue to operate.
Page 79
B8G000880_D - Operaon