Lincoln Electric IM420-D manual SET-UP for Various Procedures, Remote Output Control Optional

B-2 INSTALLATION B-2

Remote Output Control - (Optional)

The K775 Remote Output Control consists of a control box with 28 ft. (8.4m) of four conductor cable. This connects to terminals 75, 76, 77 on the terminal strip, and the case grounding screw so marked with the

symbol on the machine. These terminals are made available by opening the terminal access cover on the left side of the case front. This control will give the same control as the output control on the machine.

Mode Switch

The toggle switch labeled C (I) Innershield, CV(S) Submerged Arc, CC (or Variable Voltage) is used to select the proper welder characteristics for the process being used. The CC (or Variable Voltage) mode is primarily available for use with older wire feeding equipment such as the LAF-3, LT-34 and so forth. Use of this type of older equipment requires the addition of an NL Option Kit.

SET-UP FOR VARIOUS PROCEDURES

1.Selection of mode switch position - There are several general rules to follow in the selection of the mode switch position.

a.Use the CV(I) mode for all FCAW and GMAW processes. The CV(I) mode is also used for air carbon arc using carbon rods up to and including 5/8” (15.9mm) dia.

Welding with NR®-151, 202, 203 and other electrodes below 20 volts, is not recommend- ed.

b.Use the CV(S) mode for all submerged arc welding. This applies to both low and high travel speeds.

c.The CC (Variable Voltage) mode is available for high current large puddle submerged arc procedures that cannot be done as well with the constant voltage mode. CC mode should be used for 3/16” (4.8mm) diameter electrode and above where high current surges cause machine shutdown when starting. This occurs primarily when the slag ball is not cut from the electrode prior to starting. (Also requires a wire feeder that has a constant current mode - i.e. NA-3S).

NOTE: Some processes and procedures may be bet- ter with the mode switch in the other CV position. If the mode switch position initially selected is not pro- ducing the desired results, then place the mode switch in the other CV position and make a test weld. Then use the CV mode switch position that gives the desired results.

2.NA-3 - The NA-3 should be set for the mode being used on the power source. If using either of the CV modes, the NA-3 CC board switch should be set for CV. If the power source is used in the CC mode, then the NA-3 CC board mode switch should be placed in the CC position.

All the NA-3’s when used with the DC-1000 are capa- ble of cold starting with the constant current board mode switch in CC. Cold starting permits the wire to be inched down to the work, automatically stop, and automatically energize the flux hopper valve. All NA- 3’s made after September, 1976 are capable of cold starting on either CV or CC settings of the constant current board.

On the NA-3, set the open circuit voltage control to the same dial setting as the arc voltage control. If the pro- cedure has not yet been established, a good starting point is to set the OCV to #6.

Run a test weld, setting the proper current, voltage and travel speed. Once the proper welding procedure is established and if the start is poor - wire blast off, stub, etc. - adjust the NA-3 OCV and inch speed con- trols for optimum starting. In general, a low inch speed and an OCV dial setting identical to the voltage dial setting will provide the best starting.

To further optimize starting, adjust the OCV by making repeated starts and observing the NA-3 voltmeter action. With proper adjustment of the OCV control, the voltmeter needle will swing smoothly up to the desired

arc voltage and thus provide repeatable starts.

If the voltmeter swings above the set voltage and then backtootohighthe desired welding voltage, the OCV setting

is . This usually results in a bad start where the wire tends to “blast off”.

before

If the voltmeter needle hesitates too cominglow up to

the desired voltage, the OCV is set . This will cause the electrode to stub.

IDEALARC® DC-1000