Edwards SCU-350 Series

SCU-350 Series Control Unit for Turbomolecular Pump
MT-21E-201-E
Page 77
6
MAINTENANCE
6.1.3 Abnormal state of magnetic bearing
CAUTION
When an abnormality/error occurs in the magnetic bearing, check the STP pump as well as the
SCU-350.
If "FAILURE" cannot be released after reset operation, contact Service office.
When the magnetic bearing does not function normally due to a breakage of the STP connection
cable, disconnection of connectors or any abnormality/error of the STP control circuit, the rotor lands
on the touch down bearing and stops. The "FAILURE" LED illuminates and the LCD displays error
message "DISTURBANCE".
6.1.4 Excessive vibration
When serious vibration or mechanical shock causes the rotor to come in contact with the touch down
bearing (due to external vibration/impact, intrusion of atmosphere or foreign matter into the STP pump
or rotor imbalance), the STP pump decelerates and stops.
The "FAILURE" LED illuminates and the LCD displays error message "DISTURBANCE".
6.1.5 Motor driver overload
When the STP pump does not attain the rated speed within approximately 10 minutes after starting or
when the ACCELERATION state remains unchanged during operation for approximately 10 minutes,
the STP pump decelerates and stops.
The "FAILURE" LED illuminates and the LCD displays error message "OVERLOAD".
6.1.6 Overheating inside the STP pump
When the motor inside the STP pump overheats due to an abnormal high temperature or overload
operation, the STP pump decelerates and stops.
The "FAILURE" LED illuminates and the LCD displays error message "PUMP OVERTEMP".
6.1.7 Overheating inside the SCU-350
The temperature in the SCU-350 increases when the ventilating duct is blocked or the ambient
temperature is high. When the inside of the SCU-350 overheats, the STP pump decelerates and
stops.
The "FAILURE" LED illuminates and the LCD displays error message "CONTROLLER OT".