Lincoln Electric IM690-A manual Electrode and Work Cable Connections, Negative Electrode Polarity

A-6 INSTALLATION A-6

ELECTRODE AND WORK CABLE CONNECTIONS

Connect a work lead of sufficient size and length (Per Table 1) between the proper output terminal on the power source and the work. Be sure the connection to the work makes tight metal-to-metal electrical contact. To avoid interference problems with other equipment and to achieve the best possible operation, route all cables directly to the work or wire feeder. Avoid excessive lengths and do not coil excess cable. Do not tightly bundle the electrode and work cables together.

Use K1796 Coaxial welding cables wherever possible. (See Section F-5 Connection Diagram).

Minimum work and electrode cables sizes are as follows:

TABLE 1

(Current (60% Duty Cycle) MINIMUM COPPER WORK CABLE SIZE AWG

	Up To-100 Ft. Length (30 m)
400 Amps	2/0 (67 mm2)
500 Amps	3/0 (85 mm2)
600 Amps	3/0 (85 mm2)

NOTE: K1796 coaxial welding cable is recommended to reduce the cable inductance in long distance Pulse and STT applications up to 300 amps.

When using an inverter type power source like the Power Waves, use the largest welding (electrode and ground) cables that are practical. At least 2/0 copper wire - even if the average output current would not normally require it.

CAUTION

When pulsing, the pulse current can reach very high levels. Voltage drops can become excessive, leading to poor welding characteristics, if under- sized welding cables are used.

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Most welding applications run with the electrode being positive (+). For those applications, connect one end of the electrode cable to the positive (+) output stud on the power source (located beneath the spring loaded output cover near the bottom of the case front). Connect the other end of the electrode cable to the wire drive feed plate using the stud, lockwasher, and nut provided on the wire drive feed plate. The electrode cable lug must be against the feed plate. Be sure the connection to the feed plate makes tight metal-to-metal electrical contact. The electrode cable should be sized according to the specifications given in the work cable connections section. Connect a work lead from the negative (-) power source output stud to the work piece. The work piece connection must be firm and secure, especially if pulse welding is planned.

CAUTION

Excessive voltage drops caused by poor work piece connections often result in unsatisfactory welding performance.

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When welding with the STT process, use the positive output connection labeled (STT) for STT welding. (If desired, other welding modes can be used on this stud; however, their average output current will be lim- ited to 325 amps.) For non-STT processes, use the positive output connection labeled (Power Wave), so that the full output range of the machine is available.

CAUTION

Do not connect the STT and Power Wave stud together. Paralleling the studs will bypass STT cir- cuitry and severely deteriorate STT welding perfor- mance. (See Section F-3 Connection Diagram)

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NEGATIVE ELECTRODE POLARITY

When negative electrode polarity is required, such as in some Innershield applications, reverse the output connections at the power source (electrode cable to the negative (-) stud, and work cable to the positive (+) stud).

When operating with electrode polarity negative the switch 7 must be set to ON on the Wire Feed Head PC Board. The default setting of the switch is OFF to rep- resent positive electrode polarity.

Set the Negative Polarity switch on Wire Feed Head PC board as follows:

WARNING

ELECTRIC SHOCK can kill.

• Do not touch electrically live parts or electrodes with your skin or wet clothing.

•Insulate yourself from the work and ground.

•Always wear dry insulating gloves.

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1.Turn off power to the power source at the disconnect switch.

2.Remove the front cover from the power source.

3.The wire feed head board is on the right side of

the power source. Locate the 8-position DIP	8
	6 7
switch and look for switch 7 of the DIP switch.
	5
4. Using a pencil or other small object, slide the	4
switch right to the OFF position for positive	3
	2
electrode polarity. Conversely, slide the switch
	1
left to the ON position for negative electrode
	O N
polarity.

POWER WAVE 455/R