Edwards STP-iX455, Instruction Manual

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STP-iX455/iXL455 Series Instruction Manual
11-1
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11 Safety Functions
11.1 Power Failure
11.1.1 Operation at a Power Failure
When the power voltage of the external power supply unit drops less than 43 V DC due
to a power failure or other, the normal operation of the magnetic bearing is maintained
using the regenerative energy of the rotating rotor (backup operation during a power
failure).
1) When the rotational speed is approx. 20,000 rpm or more at a power failure:
The STP pump detects any power failure of 2 seconds or more and decelerates.
At this time, the "POWER" LED extinguishes and the "FAILURE" LED (red)
illuminates. Also, POWER OUT pins (4)–(16) is opened, and a failure signal is
output from FAILURE OUT pins (8)–(21) and (9)–(21) of the "X2 REMOTE"
connector.
When the rotational speed goes down to approx. 20,000 rpm, the rotor lands on
the touch down bearing and stops. All lamps extinguish.
The STP pump does not detect a power failure of less than 2 seconds and the STP
pump will continue to rotate.
2) When the rotational speed is less than approx. 20,000 rpm at a power failure:
The STP pump does not detect the power failure. The rotor lands on the touch
down bearing and stops.
Table 11.1 shows the states of LED output and the "X2 REMOTE" output signals at a
power failure.
Table 11.1 States of Lamps and X2 REMOTE Output Signals at Power Failure
Rotational speed
Duration of
power failure
LED output X2 REMOTE output signal
POWER FAILURE POWER FAILURE
LED LED N.O OUT N.O OUT N.C OUT
20,000 rpm
or more
Approx. 2 sec.
or longer
Extinguish Illuminate Open Close Open
Shorter than
approx. 2 sec.
Continues as before
Less than
20,000 rpm
Extinguish Extinguish Open Open Close