Lincoln Electric IM714 POWER WAVE 455 - Manual (Page 12)

A-4 INSTALLATION
POWER WAVE 455
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 50 feet, traditional
welding cables may be used without any effects on
welding performance. For the total welding loop length
greater than 50 feet, the K1796 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.2).
For long work piece lengths, a sliding ground should
be considered to keep the total welding loop length
less than 50 feet. (See Figure A.3.)
Output connections on some Power Waves are made
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 elec-
trode 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 con-
nection 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.
For additional Safety information regarding the elec-
trode and work cable set-up, See the standard "SAFE-
TY 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, 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
"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 instruction
manual for further details.
VOLTAGE SENSING
The best arc performance occurs when the
PowerWaves have accurate data about the arc condi-
tions. Depending upon the process, inductance within
the electrode and work lead cables can influence the
voltage apparent 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 series) 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 con-
trol cable, and is automatically enabled for all semi-
automatic processes. The WORK sense lead (21) con-
nects to the Power Wave at the four pin connector
located underneath the output stud cover. By default
the WORK voltage is monitored at the output stud in
the Power Wave 455. For more information on 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-455 by default.
CAUTION
CAUTION
B
A
C
FIGURE A.2
POWER
WAVE
WORK
A
C
B
POWER
WAVE
FIGURE A.3
K1796 COAXIAL CABLE
MEASURE FROM END
OF OUTER JACKET OF
CABLE
C
A
B
WORK
SLIDING GROUND