Olicom 9600 - Manual (Page 41)

Operation
4-2 P/N 8040540
C
HELIX TECHNOLOGY CORPORATION
- TI CRYOGENICS
NOTE: The use of a higher helium charge pressure for 50 HZ operation is
necessary in order to compensate for the slower speed at which the
compressor operates at 50 HZ. The static charge level for 60 Hz remains
at 240-250 PSIG.
CAUTION
Exceeding the recommended system static helium charge pressure will
result in the compressor and cryopump safety relief valves opening and
releasing excess helium gas.
5. If the static helium charge pressure is not within the ranges as indi-
cated in Table 4-1, then adjust the charge pressure as described in
Section 5- Maintenance.
Compressor Operation
The system may be operated once the helium charge pressure is correct.
Perform the following steps to start the compressor:
1. Set the System Circuit Breaker to the ON (UP) position.
2. Set the Control Circuit Breaker to the ON (UP) position.
3. Close all Cryopump gate valves.
4. Refer to the On-Board Module Programming and Operation
manual or Cryo-Torr Cryopump Installation and Service man-
ual (that came with your cryopump) and perform the cryopump
start-up procedure.
5. Once the second stage temperature for all cryopumps is below 17K,
record the compressor pressure gauge reading as the normal system
operating pressure.
NOTE: During compressor operation, the compressor gauge reads the
pressure of the gas entering the compressor prior to it being compressed.
6. Affix a copy of the data next to the compressor gauge on each com-
pressor. This data is to be verified for each tool installation and
whenever a configuration change is made affecting the amount of
system helium gas and line volume.
The compressor pressure reading will decrease from the normal system
operating pressure during cryopump regeneration or if fewer cryopumps
are being operated. These are normal variations in the compressor pressure
reading and should not be cause for concern.