Commissioning | 6
Instruction Manual COBRA NC 2500 B WCV_EN_en
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• Make sure that the installation conditions (see
met.
• Turn on the water supply.
If the machine is equipped with a barrier gas system:
• Turn on the barrier gas supply.
• Adjust the barrier gas pressure and volume flow.
• Switch on the machine.
• Make sure that the maximum permissible number of starts does not exceed 6 starts
per hour. Those starts should be spread within the hour.
• Make sure that the operating conditions comply with the
.
• After a few minutes of operation, perform an
.
• After a few minutes of operation, perform a
Cooling Liquid Level Inspection [
.
As soon as the machine is operated under normal operating conditions:
• Measure the motor current and record it as reference for future maintenance
and troubleshooting work.
6.1 Recommendations on Operation
6.1.1 Operating frequency
Operate the machine continuously at 35 ... 60 Hz (2100 ... 3600 min
-1
).
For continuous operation at 20 ... 35 Hz, for example for stand-by purposes, an accel-
eration ramp of 12 minutes for 0 … 60 Hz must be used (acceleration of 5 Hz per min-
ute) or the inlet pressure must be kept at >100 mbar for cooling purposes. The G 1/2
connection at the machine inlet spool piece can be used to inject ambient cooling air.
Operation below 20 Hz is not recommended.
Maximum allowed operation frequency is 60 Hz (3600 min
-1
).
6.1.2 Stop & Start
Frequent stop-start operation to avoid. Use acceleration ramp of 12 minutes for
0 … 60 Hz for start.
Or, for fast start (30 seconds for 0 … 60 Hz), wait >60 minutes between stop and start.
6.1.3 Use with Argon
Pumping of high Argon concentrations (up to 50-80% of Argon) requires additional lim-
its of operation:
– Rotational speed: max 50 Hz = 3000 min
-1
– Gas inlet temperature: max. 80 °C
– Cooling gas: air or nitrogen
– Temperature monitoring: standard setting
