Hypertherm HT4100 Plasma Arc Cutting System Operating - Manual (Page 30)

3-4
OPERATION
HT4100 Instruction Manual: Operation
FRONT PANEL CONTROLS AND INDICATORS (Cont.)
Gas Console (Fig. 3-3)
• PLASMA N
2
/O
2
Toggle Switch (S1)
The O
2
position selects oxygen as the plasma cutting gas. The N
2
position is for the
future availability of nitrogen as the plasma cutting gas.
• Test Preflow/Run/Test Cut Flow Toggle Switch (S2)
Test Preflow - This test position is used when setting the plasma and shield gas preflow
flow rates on the flowmeters for plasma oxygen cutting as specified in the
Cut Charts on
pages 3-12 to 3-13. A nitrogen and oxygen mixture is used as the preflow gas in order to
promote easier starts and longer electrode life when using oxygen. In this position the
contactor is disabled, so that current is not delivered to the electrode and the arc cannot
be fired.
• PLASMA O
2
(FM1) and N
2
(FM3) flowmeters - In test preflow, indicate the percentage of
nitrogen and oxygen required for the preflow gas mixture for oxygen cutting.
• PLASMA Preflow O
2
(MV1) and N
2
(MV4) metering valves - Adjusts plasma gas preflow.
• SHIELD O
2
(FM2) and N
2
(FM4) flowmeters - In test preflow, indicate the percentage of
nitrogen and oxygen required for the shield preflow gas mixture.
• SHIELD Preflow O
2
(MV3) and N
2
(MV6) metering valves - Adjusts shield gas preflow.
Test Cut Flow - This test position is used when setting the plasma and shield gas flow
rates on the flowmeters for cutting conditions as specified in the
Cut Charts on pages
3-12 to 3-13. In this position the contactor is disabled, so that current is not delivered to
the electrode and the arc cannot be fired.
• PLASMA O
2
flowmeter (FM1) - In test cut flow, indicates the percentage of plasma
(oxygen) gas flow required for cutting conditions.
• PLASMA Cut Flow Toggle switch (S3) - This switch controls a motor-driven metering
valve in the motor valve console which adjusts the plasma gas (oxygen) in test cut flow.
• SHIELD O
2
(FM2) and N
2
(FM4) flowmeters - In test operate, indicate the percentage of
nitrogen and oxygen required for cutting conditions.
• SHIELD Cut Flow O
2
(MV2) and N
2
(MV5) metering valves - Adjusts shield gas test cut
flow.
Run - This position enables the contactor and the subsequent firing of the arc after the
gas flow rates have been set in the Test Preflow and Test Cut Flow positions.