Chicago Electric 91110 User manual

INVERTER ARC WELDER -
80 AMP
Model 91110
SET UP AND OPERATING INSTRUCTIONS
Distributed exclusively by Harbor Freight Tools®.
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright©2004 by Harbor Freight Tools®. All rights reserved. No portion of this manual or any
artwork contained herein may be reproduced in any shape or form without the express written
consent of Harbor Freight Tools. Diagrams within this manual may not be drawn proportionally. Due
to continuing improvements, actual product may differ slightly from the product described herein.
For technical questions or replacement parts, please call 1-800-444-3353.
Revised 08b

Page 2SKU 91110 For technical questions, please call 1-800-444-3353.
GENERAL SAFETY RULES
WARNING Read all safety
warnings and instructions.
Failure to follow the warnings and
instructions may result in electric
shock, re and/or serious injury.
WORK AREA
Keep your work area clean and1.
well lit. Cluttered benches and dark
areas invite accidents.
Do not operate power tools in2.
explosive atmospheres, such as in
the presence of ammable liquids,
gases, or dust. Power tools create
sparks which may ignite the dust or
fumes.
Keep bystanders, children, and3.
visitors away while operating a
power tool. Distractions can cause
you to lose control. Protect others
in the work area from debris such as
chips and sparks. Provide barriers or
shields as needed.
SPECIFICATIONS
Electrical Input 120 V~ / 60 Hz / 20 A
Power Cord: 12 Gauge With 3-Prong Plug
Thermal Overload Protection
Electrode Sizes 1/16” - 3/32” (1.6mm) - (2.5mm)
Duty Cycles 35% @ 80 A
60% @ 65 A
100% @ 50 A
Electrode Cable 6 Gauge x 6’ Long
Ground Clamp Cable 6 Gauge x 5’6” Long
Overall Dimensions 9-1/2” x 5-5/8” x 3-3/4”
Additional Features Amber Temperature Warning Light
Welding Capacity 6 Gauge Steel
SAVE THIS MANUAL
You will need this manual for the safety warnings and precautions, assembly,
operating, inspection, maintenance and cleaning procedures, parts list and assembly
diagram. Keep your invoice with this manual. Write the invoice number on the inside
of the front cover. Keep this manual and invoice in a safe and dry place for future refer-
ence.
UNPACKING
When unpacking, check to make sure all the parts shown on the Parts List are
included. If any parts are missing or broken, please call Harbor Freight Tools at the
number shown on the cover of this manual as soon as possible.

Page 3SKU 91110 For technical questions, please call 1-800-444-3353.
ELECTRICAL SAFETY
Grounded tools must be plugged1.
into an outlet properly installed
and grounded in accordance with
all codes and ordinances. Never
remove the grounding prong or
modify the plug in any way. Do
not use any adapter plugs. Check
with a qualied electrician if you
are in doubt as to whether the
outlet is properly grounded. If the
tools should electrically malfunction
or break down, grounding provides a
low resistance path to carry electricity
away from the user.
Double insulated tools are2.
equipped with a polarized plug
(one blade is wider than the other).
This plug will t in a polarized out-
let only one way. If the plug does
not t fully in the outlet, reverse
the plug. If it still does not t, con-
tact a qualied electrician to install
a polarized outlet. Do not change
the plug in any way. Double insula-
tion eliminates the need for the
three wire grounded power cord and
grounded power supply system.
Avoid body contact with grounded3.
surfaces such as pipes, radiators,
ranges, and refrigerators. There is
an increased risk of electric shock if
your body is grounded.
Do not expose power tools to rain4.
or wet conditions. Water entering
a power tool will increase the risk of
electric shock.
Do not abuse the Power Cord.5.
Never use the Power Cord to carry
the tools or pull the Plug from an
outlet. Keep the Power Cord away
from heat, oil, sharp edges, or
moving parts. Replace damaged
Power Cords immediately. Dam-
aged Power Cords increase the risk
of electric shock.
When operating a power tool out-6.
side, use an outdoor extension
cord marked “W-A” or “W”. These
extension cords are rated for outdoor
use, and reduce the risk of electric
shock.
PERSONAL SAFETY
Stay alert. Watch what you are do-1.
ing, and use common sense when
operating a power tool. Do not use
a power tool while tired or under
the inuence of drugs, alcohol, or
medication. A moment of inatten-
tion while operating power tools may
result in serious personal injury.
Dress properly. Do not wear loose2.
clothing or jewelry. Contain long
hair. Keep your hair, clothing, and
gloves away from moving parts.
Loose clothes, jewelry, or long hair
can be caught in moving parts.
Avoid accidental starting.3. Be sure
the Power Switch is off before
plugging in. Carrying power tools
with your nger on the Power Switch,
or plugging in power tools with the
Power Switch on, invites accidents.
Remove adjusting keys or wrench-4.
es before turning the power tool
on. A wrench or a key that is left at-
tached to a rotating part of the power
tool may result in personal injury.
Do not overreach. Keep proper5.
footing and balance at all times.
Proper footing and balance enables

Page 4SKU 91110 For technical questions, please call 1-800-444-3353.
better control of the power tool in
unexpected situations.
Use safety equipment. Always6.
wear eye protection. Always wear
ANSI-approved safety glasses under
a properly shaded welding helmet.
Respirator, leather work shoes with
rubber soles, hard hat or hearing pro-
tection must be used for appropriate
conditions.
TOOL USE AND CARE
Use clamps (not included) or other1.
practical ways to secure and sup-
port the work piece to a stable
platform. Holding the work by hand
or against your body is unstable and
may lead to loss of control.
Do not force the tool. Use the cor-2.
rect tool for your application. The
correct tool will do the job better and
safer at the rate for which it is de-
signed.
Do not use the power tool if the3.
Power Switch does not turn it on
or off. Any tool that cannot be con-
trolled with the Power Switch is dan-
gerous and must be replaced.
Disconnect the Power Cord Plug4.
from the power source before
making any adjustments, changing
accessories, or storing the tool.
Such preventive safety measures
reduce the risk of starting the tool ac-
cidentally.
Store idle tools out of reach of chil-5.
dren and other untrained persons.
Tools are dangerous in the hands of
untrained users.
Maintain tools with care. Keep cut-6.
ting tools sharp and clean. Prop-
erly maintained tools with a sharp
cutting edge are less likely to bind
and are easier to control. Do not use
a damaged tool. Tag damaged tools
“Do not use” until repaired.
Check for misalignment or binding7.
of moving parts, breakage of parts,
and any other condition that may
affect the tool’s operation. If dam-
aged, have the tool serviced before
using. Many accidents are caused
by poorly maintained tools.
Use only accessories that are8.
recommended by the manufac-
turer for your model. Accessories
that may be suitable for one tool may
become hazardous when used on
another tool.
SERVICE
Tool service must be performed1.
only by qualied repair personnel.
Service or maintenance performed by
unqualied personnel could result in
a risk of injury.
When servicing a tool, use only2.
identical replacement parts. Fol-
low instructions in the “Inspec-
tion, Maintenance, And Cleaning”
section of this manual. Use of
unauthorized parts or failure to follow
maintenance instructions may create
a risk of electric shock or injury.
SPECIFIC SAFETY RULES
Maintain a safe working environ-1.
ment. Keep the work area well lit.
Make sure there is adequate sur-
rounding workspace. Always keep

Page 5SKU 91110 For technical questions, please call 1-800-444-3353.
the work area free of obstructions,
grease, oil, trash, and other debris.
Do not use the Inverter Arc Welder
in areas near ammable chemicals,
dusts, and vapors.
Maintain labels and nameplates2.
on the Inverter Arc Welder. These
carry important information. If un-
readable or missing, contact Harbor
Freight Tools for a replacement.
Never plug the Power Cord of this3.
product into an electrical outlet
while standing on a wet or damp
surface.
Do not unplug the Inverter Arc4.
Welder by pulling on the Power
Cord. Keep the Power Cord away
from heated surfaces.
Always turn off the Inverter Arc5.
Welder and unplug the unit from
its electrical outlet before perform-
ing any inspection, maintenance,
or cleaning procedures.
Never leave the Inverter Arc Weld-6.
er unattended when it is plugged
into an electrical outlet. Make sure
to unplug it from its electrical outlet
before leaving the area.
Do not allow children to handle or7.
play with this product.
Store idle equipment.8. When not in
use, tools and equipment should be
stored in a dry location to inhibit rust.
Always lock up tools and equipment,
and keep out of reach of children.
Do not use this product if under9.
the inuence of alcohol or drugs.
Read warning labels on prescrip-
tions to determine if your judgement
or reexes are impaired while taking
drugs. If there is any doubt, do not
attempt to use this product.
WARNING
INHALATION HAZARD:
Welding and Plasma Cutting Produce
TOXIC FUMES.
Exposure to welding or cutting
exhaust fumes can increase the risk
of developing certain cancers, such as
cancer of the larynx and lung cancer.
Also, some diseases that may be linked
to exposure to welding or plasma cutting
exhaust fumes are:
• Early onset of Parkinson’s Disease
• Heart disease • Ulcers
• Damage to the reproductive organs
• Inammation of the small intestine or
stomach • Kidney damage
• Respiratory diseases such as
emphysema, bronchitis, or pneumonia
Use natural or forced air ventilation and
wear a respirator approved by NIOSH to
protect against the fumes produced to
reduce the risk of developing the above
illnesses.
Use eye, skin, and breathing pro-11.
tection. Always wear ANSI approved
safety glasses with side shields under
an ANSI approved welding helmet.
Wear re resistant work gloves, a
heavy, long-sleeved shirt, trousers
without cuffs, high top leather work
boots to protect skin from arc rays
and metal sparks. Also wear an ANSI
approved air respirator.
REV 04e

Page 6SKU 91110 For technical questions, please call 1-800-444-3353.
Industrial applications must follow12.
OSHA requirements.
Maintain this product with care.13.
Keep this product clean and dry for
better and safer performance.
Maintenance:14. For your safety,
service and maintenance should be
performed regularly by a qualied
technician.
Check for damaged parts.15. Before
using this product, carefully check
that it will operate properly and per-
form its intended function. Check for
damaged parts and any other condi-
tion that may affect the operation of
this product. Replace or repair dam-
aged or worn parts immediately.
Connect the earth ground as near16.
as possible to the operating area.
Earth connections to structural
parts of the building or other plac-
es distant to the operating area
will reduce their effectiveness and
increase the danger of electric
shock.
Do not pass equipment cables17.
through or near lifting chains,
crane cables, or any electrical
lines.
In addition to grounding the work18.
piece with the Inverter Arc Welder
Grounding Cable, an earth ground-
ing of the work piece is recom-
mended. Ground it directly to an
earth pipe or grounding rod with a
separate cable of appropriate size.
IMPORTANT: Only a qualied, certi-
ed electrician should perform this
procedure.
Do not touch the electrode if you19.
are in contact with the work piece,
ground, or another electrode from
a different machine.
Never use the Inverter Arc Welder20.
near water. Ensure that the sur-
rounding area and cutting objects
are dry. Do not spray water or other
liquids on or near the Inverter Arc
Welder.
Avoid all direct contact between21.
the skin and wet garments and
metal parts under electrical power.
Check that gloves and protective
clothing are dry.
Always wear welding gloves and22.
rubber soled leather work boots
when working in damp areas or
standing on metal objects.
Always turn off the Inverter Arc23.
Welder in the event of a power
failure.
Do not allow the Electrode Holder24.
to touch earth ground. Accidental
earth discharges may cause over-
heating and re hazards.
Signicant DC voltage exists af-25.
ter turning off and unplugging the
Inverter Arc Welder. Discharge the
electrode to ground before handling.
Position a re-resistant screen 26. (not
included) around the welding area
to protect people in the vicinity
from arc rays, sparks, and slag.
Clear away or protect ammable 27.
objects. Protect objects such as
wood, sawdust, clothing, paints,
solvents, petroleum products, natural
gas, acetylene, propane, and other
substances with reproof material
(not included).

Page 7SKU 91110 For technical questions, please call 1-800-444-3353.
Keep an ABC type re extinguisher 28.
near the work area.
Never perform welding or cutting29.
operations on closed pipes or
containers, as the possible internal
fumes may cause an explosion.
Never perform welding or cutting30.
operations on open pipes or con-
tainers that may have come in con-
tact with moisture, chemicals, or
ammable materials. Always clean
and dry the areas rst.
Welding and cutting fumes and31.
gases may be hazardous if inhaled
for long periods of time.
Install a natural or forced-air ven-32.
tilation system in the work area. If
the ventilation system is inadequate,
use an air respirator.
Use a forced-air ventilation system33.
when welding or cutting lead, be-
ryllium, cadmium, zinc, zinc-coat-
ed or painted materials. Always
wear an air respirator.
When welding or cutting in small34.
areas, the operator should be
externally accompanied by an-
other person (standing near the
enclosed work area) to observe
accident prevention procedures.
Do not perform welding or cut-35.
ting operations near chlorinated
hydrocarbon vapors produced by
degreasing or painting. The heat
generated by arc rays can react to
form phosgene, a highly toxic gas.
Irritation of the eyes, nose, and36.
throat are symptoms of inadequate
ventilation. Take immediate steps to
improve ventilation. Do not continue
operations if symptoms persist.
Electric shock can be fatal.37. Never
touch exposed electrical parts.
Switch off and disconnect the38.
power source before installing the
Inverter Arc Welder.
Installation must be performed by39.
a qualied technician. Installation
procedures must comply with the
National Electric Code, and all other
relevant regulations.
When welding or cutting, be aware40.
that high frequency radiation may
be produced which can interfere
with radio navigation, safety de-
vices, computers, and communica-
tions equipment. Before operating,
have a qualied technician check out
that possibility.
Keep high frequency source doors41.
and panels tightly shut. Keep
spark gaps at the correct settings.
Use proper grounding and shielding
to minimize the possibility of interfer-
ence. Keep all cables close together
and close to the ground. Locate the
welding or cutting operation as far
as possible from sensitive electronic
equipment, or have the electronic
equipment shut down temporarily.
Performance of this Inverter Arc42.
Welder may vary depending on
variations in local line voltage.
Extension cord usage may also affect
tool performance.
Welding and cutting operations are43.
a source of radiation, noise, heat,
and noxious fumes. The protec-
tion of the operator and any specta-
tors must be guaranteed with suit-

Page 8SKU 91110 For technical questions, please call 1-800-444-3353.
able safety devices and precautions.
Never approach arc rays or hot metal
without protection. Failure to observe
these standards during operation
could lead to serious health risks.
Use the right tool or attachment44.
for the right job. Do not attempt to
force a small tool or attachment to do
the work of a larger industrial tool or
attachment. There are certain ap-
plications for which this product was
designed. It will do the job better
and more safely at the rate for which
it was intended. Do not modify this
product, and do not use this product
for a purpose for which it was not
intended.
Replacement parts and acces-45.
sories: When servicing, use only
identical replacement parts. Only use
accessories intended for use with this
product.
WARNING: The brass components46.
of this product contain lead, a chemi-
cal known to the State of California
to cause birth defects (or other repro-
ductive harm). (California Health &
Safety code § 25249.5, et seq.)
WARNING: This product, when used47.
for welding, plasma cutting, solder-
ing, or similar applications, produces
chemicals known to the State of
California to cause cancer and birth
defects (or other reproductive harm).
(California Health & Safety Code §
25249.5, et seq.)
People with pacemakers should48.
consult their physician(s) before use.
Electromagnetic elds in close prox-
imity to heart pacemaker could cause
pacemaker interference or pacemak-
er failure. In addition, people with
pacemakers should:
Avoid operating alone.•
Don’t use with power switch locked•
on.
Properly maintain and inspect to•
avoid electrical shock.
Any power cord must be properly•
grounded. Ground Fault Circuit
Interrupter (GFCI) should also be
implemented – it prevents sustained
electrical shock.
The warnings, precautions, and in-49.
structions discussed in this instruction
manual cannot cover all possible con-
ditions and situations that may occur.
It must be understood by the operator
that common sense and caution are
factors which cannot be built into this
product, but must be supplied by the
operator.

Page 9SKU 91110 For technical questions, please call 1-800-444-3353.
GROUNDING
TO PREVENT
ELECTRIC SHOCK
AND DEATH FROM
INCORRECT GROUNDING
WIRE CONNECTION:
Check with a qualied
electrician if you are in doubt
as to whether the outlet is
properly grounded. Do not
modify the power cord plug
provided with the tool. Never
remove the grounding prong
from the plug. Do not use the
tool if the power cord or plug
is damaged. If damaged, have
it repaired by a service facility
before use. If the plug will not
t the outlet, have a proper
outlet installed by a qualied
electrician.
Grounded Tools: Tools with Three
Prong Plugs
1. Tools marked with “Grounding Re-
quired” have a three wire cord and
three prong grounding plug. The
plug must be connected to a properly
grounded outlet. If the tool should
electrically malfunction or break
down, grounding provides a low
resistance path to carry electricity
away from the user, reducing the risk
of electric shock. (See 3-Prong Plug
and Outlet.)
The grounding prong in the plug is2.
connected through the green wire in-
side the cord to the grounding system
in the tool. The green wire in the cord
must be the only wire connected to
the tool’s grounding system and must
never be attached to an electrically
“live” terminal. (See 3-Prong Plug
and Outlet.)
The tool must be plugged into an3.
appropriate outlet, properly installed
and grounded in accordance with all
codes and ordinances. The plug and
outlet should look like those in the
preceding illustration. (See 3-Prong
Plug and Outlet.)
Double Insulated Tools: Tools
with Two Prong Plugs
1. Tools marked “Double Insulated” do
not require grounding. They have
a special double insulation system
which satises OSHA requirements
and complies with the applicable
standards of Underwriters Labora-
tories, Inc., the Canadian Standard
Association, and the National Electri-
cal Code. (See Outlets for 2-Prong
Plug.)

Page 10SKU 91110 For technical questions, please call 1-800-444-3353.
Double insulated tools may be used2.
in either of the 120 volt outlets shown
in the preceding illustration. (See
Outlets for 2-Prong Plug.)
Extension Cords
Grounded1. tools require a three wire
extension cord. Double Insulated
tools can use either a two or three
wire extension cord.
As the distance from the supply outlet2.
increases, you must use a heavier
gauge extension cord. Using exten-
sion cords with inadequately sized
wire causes a serious drop in voltage,
resulting in loss of power and pos-
sible tool damage.
(See Table A.) The smaller the
gauge number of the wire, the greater
the capacity of the cord. For ex-
ample, a 14 gauge cord can carry a
higher current than a 16 gauge cord.
(See Table A.)
When using more than one exten-3.
sion cord to make up the total length,
make sure each cord contains at
least the minimum wire size required.
(See Table A.)
If you are using one extension cord4.
for more than one tool, add the
nameplate amperes and use the sum
to determine the required minimum
cord size. (See Table A.)
If you are using an extension cord5.
outdoors, make sure it is marked with
the sufx “W-A” (“W” in Canada) to
indicate it is acceptable for outdoor
use.
Make sure the extension cord is prop-6.
erly wired and in good electrical con-
dition. Always replace a damaged
extension cord or have it repaired by
a qualied electrician before using it.
Protect the extension cords from7.
sharp objects, excessive heat, and
damp or wet areas.
RECOMMENDED MINIMUM WIRE
GAUGE FOR EXTENSION CORDS*
(120/240 VOLT)
NAMEPLATE
AMPERES
(at full load)
EXTENSION CORD
LENGTH
25’ 50’ 75’
100’ 150’
0 – 2.0 18 18 18 18 16
2.1 – 3.4 18 18 18 16 14
3.5 – 5.0 18 18 16 14 12
5.1 – 7.0 18 16 14 12 12
7.1 – 12.0 18 14 12 10 -
12.1 – 16.0 14 12 10 - -
16.1 – 20.0 12 10 - - -
TABLE A
* Based on limiting the line
voltage drop to ve volts at
150% of the rated amperes.
Symbology
Double Insulated
Canadian Standards Association
Underwriters Laboratories, Inc.
V~ Volts Alternating Current
AAmperes
n0xxxx/min. No Load Revolutions per Minute
(RPM)