Cable Inductance, And Its Effects On Pulse Welding; Negative Electrode Polarity; Voltage Sensing - Lincoln Electric Power Wave 455M Operator's Manual

A-4
CABLE INDUCTANCE, AND ITS EFFECTS
ON PULSE WELDING
For Pulse Welding processes, cable inductance will
cause the welding performance to degrade. For the
total welding loop length less than
traditional welding cables may be used without any
effects on welding performance. For the total welding
loop length greater than
Coaxial Welding Cables are recommended. The
welding loop length is defined as the total of electrode
cable length (A) + work cable length (B) + work length
(C) (See Figure A.3).
FIGURE A.3
POWER
WAVE
For long work piece lengths, a sliding ground should
B
be considered to keep the total welding loop length
less than 15.24m). (See Figure A.4.)
50 ft.(
FIGURE A.4
FIGURE A.4
POWER
WAVE
K1796 COAXIAL CABLE
MEASURE FROM END
OF OUTER JACKET OF
CABLE
Output connections on some Power Waves
via 1/2-13 threaded output studs located beneath the
spring loaded output cover at the bottom of the case
front.
Most welding applications run with the electrode being
positive (+). For those applications, connect the
electrode cable between the wire feeder and 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. 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.
INSTALLATION
15.24m),
50 ft.(
15.24m), the K1796
50 ft.(
A
C
WORK
A A
C WORK
B B
SLIDING WORK
are made
®
POWER WAVE
For additional Safety information regarding the
electrode and work cable set-up, See the standard
"SAFETY INFORMATION" located in the front of the
Instruction Manuals.
Excessive voltage drops caused by poor work
piece connections often result in unsatisfactory
welding performance.
------------------------------------------------------------------------

NEGATIVE ELECTRODE POLARITY

When negative electrode polarity is required, such as
in some Innershield applications, switch 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
"Electrode Sense Polarity" DIP switch must be set to
the "Negative" position on the Wire Drive Feed Head
PC Board. The default setting of the switch is positive
electrode polarity. Consult the Power Feed
manual for further details.

VOLTAGE SENSING

The best arc performance occurs when the Power
Waves have accurate data about the arc conditions.
®
Depending upon the process, inductance within the
C
electrode and work lead cables can influence the
apparent voltage at the studs of the welder. Voltage
sense leads improve the accuracy of the arc
conditions and can have a dramatic effect on
performance. Sense Lead Kits (K940-10, -25 or -50)
are available for this purpose.
If the voltage sensing is enabled but the sense
leads are missing, improperly connected, or if the
electrode polarity switch is improperly configured,
extremely high welding outputs may occur.
------------------------------------------------------------------------
The ELECTRODE sense lead (67) is built into the
control cable, and is automatically enabled for all semi-
automatic processes. The WORK sense lead (21)
connects to the Power Wave
located underneath the output stud cover. By default
the WORK voltage is monitored at the output stud in
the POWER WAVE
the WORK sense lead (21), see "Work Voltage
Sensing" in the following paragraph.
All constant current processes sense the voltage at the
output studs of the POWER WAVE
455M
®
CAUTION
instruction
®
CAUTION
at the four pin connector
®
455M. For more information on
®
455M by default.
®
A-4