HTP MicroCut 875S User manual

MicroCut 875S

Index
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Plasma/Cooling Gas Connection . . . . . . . . . . . . . . . . . . 7
Electrical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MicroCut 875S Controls . . . . . . . . . . . . . . . . . . . . . . . . . 8
Ground Cable Connection . . . . . . . . . . . . . . . . . . . . . . . . 9
Plasma Torch Connection . . . . . . . . . . . . . . . . . . . . . . . . 9
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Maintenance and Service . . . . . . . . . . . . . . . . . . . . . . . . 10
Cutting Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
MicroCut 875S Plasma Torch Parts Breakdown . . . . . . . 12
MicroCut 875S Parts Breakdown . . . . . . . . . . . . . . . . . . 13-16
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Introduction
Congratulations on your purchase of an HTP America Micro Cut 875S Air Plasma
Cutting System. Your purchase of a Micro Cut 875S means you have purchased one
of the most technologically advanced, safest and economical plasma cutters
available today.
The owner's manual has been designed to instruct you on the safe operation of your
Micro Cut 875S. If you read and follow the instructions in this manual, your plasma
cutter will provide you with years of trouble free operation. If you fail to read and
understand this manual, as well as correctly follow the operating instructions, you
will significantly shorten the operating life of your plasma cutter.
Operation of your plasma cutting system without proper understanding of the facts
contained within this manual or under unsafe or hazardous conditions, may lead to
SERIOUS INJURY OR DEATH!
2

of repair or replacement will be F.O.B., Factory at
Arlington Heights, Illinois, therefore; no
compensation for transportation costs of any kind
will be allowed. Upon receipt of notice of apparent
defect or failure, HTP shall instruct the claimant on
the warranty claim procedures to be followed.
HTP America, Inc. has reserved the right to make
changes in design or add any improvements to its
products at any time without incurring any obligation
to install same on equipment.
This warranty is null and void unless warranty card
is sent to HTP America, Inc. within 15 days from
date of purchase.
ANY EXPRESS WARRANTY NOT PROVIDED
HEREIN AND ANY IMPLIED WARRANTY,
GUARANTY OR REPRESENTATION AS TO
PERFORMANCE, AND ANY REMEDY FOR
BREACH OF CONTRACT WHICH, BUT FOR
THIS PROVISION, MIGHT ARISE BY
IMPLICATION, OPERATION OF LAW, CUSTOM
OF TRADE OR COURSE OF DEALING,
INCLUDING ANY IMPLIED WARRANTY OF
MERCHANTABILITY OR OF FITNESS FOR
PARTICULAR PURPOSE, WITH RESPECT TO
ANY AND ALL EQUIPMENT FURNISHED BY
HTP IS EXCLUDED AND DISCLAIMED BY HTP.
FOR THIS PROVISION, MIGHT ARISE BY
IMPLICATION, OPERATION OF LAW, CUSTOM
OF TRADE OR COURSE OF DEALING,
INCLUDING ANY IMPLIED WARRANTY OF
MERCHANTABILITY OR OF FITNESS FOR
PARTICULAR PURPOSE, WITH RESPECT TO
ANY AND ALL EQUIPMENT FURNISHED BY
HTP IS EXCLUDED AND DISCLAIMED BY HTP.
Limited Warranty
Subject to the terms and conditions hereof, HTP
warrants to its Distributor/Dealer that all MicroCut
875S Plasma Cuffers furnished by HTP are free from
defect in workmanship and material as of the time
and place of delivery by HTP. No warranty is made
by HTP with respect to trade accessories or other
items manufactured by others. Such trade
accessories and other items are sold subject to the
warranties of their respective manufacturers, if any.
HTP shall be required to honor warranty claims on
MicroCut 875S Plasma Cuffers in the event of failure
resulting from a defect within the following periods
from the date of delivery of MicroCut 875S to the
original user:
1. Plasma cutters, power sources and
components: 2 years.
2. All plasma torches: 90 days.
3. The electrode, cutting nozzle,
insulator, spring, and gas
diffuser are consumable
items, WHICH CARRY NO WARRANTY.
provided that HTP is notified in writing within thirty
(30) days of the date of such failure.
As a matter of general policy only, HTP may honor
claims submitted by the original user within the
foregoing periods.
In the case of HTP's breach of warranty or any other
duty with respect to the quality of any goods, the
exclusive remedies therefore shall be, at HTP's option
(1) repair or (2) replacement or, where authorized in
writing by HTP in appropriate cases, (3) the
reasonable cost of repair or replacement at an
authorized HTP service station upon return of the
goods at Customer's risk and expense. HTP's option
3

Safety Precautions
Plasma Arc Cutting Hazards
▲ The safety information given below is only a summary of
the more complete safety information found in the Safety
Standards listed in Section M. Read and follow
all Safety Standards.
▲ Only qualified persons should install, operate,
maintain, and repair this unit.
▲ During operation, keep everybody, especially children, away.
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Hot metal and sparks blow out from the plasma cutting
arc. The flying sparks and hot metal, hot work pieces,
and hot equipment can cause fires and burns. Check
and be sure the area is safe before doing any cutting.
Protect yourself and others from flying sparks and hot metal.
Do not cut where flying sparks can strike flammable material.
Remove all flammables within 35 ft of the plasma cutting arc.
If this is not possible, tightly cover them with approved
covers.
Be alert that sparks and hot materials from cutting can easily
go through small cracks and openings to adjacent areas.
Watch for fire, and keep a fire extinguisher nearby.
Be aware that cutting on ceiling, floor, bulkhead, or partition
can cause fire on the opposite side.
Connect ground cable to the work as close to cutting area as
practical to prevent cutting current from traveling long,
possibly unknown paths and causing electric shock and fire
hazards.
Do not cut pressurized cylinders, pipes, or vessels.
Do not cut on closed containers such as tanks or drums.
Never cut containers with potentially flammable materials
inside- they must be emptied and properly cleaned first.
Do not cut containers that have held combustibles.
Do not cut in atmospheres containing explosive dust or
vapors.
Wear oil-free protective garments such as leather gloves,
heavy shirt, cuffless trousers, high shoes, and a cap.
Do not locate unit on or over combustible surfaces.
Remove any combustibles, such as butane lighter or matches
from your person before doing any cutting.
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Touching live electrical parts can cause fatal shocks or
severe burns. The plasma torch and circuit are
electrically live whenever the output is on. The input power
circuit and machine internal circuits are also live when power is
on. Plasma arc cutting requires higher voltages than welding to
start and maintain the arc (100 -300 volts dc are common), but
also uses torches designed with safety interlock systems which
turn off the machine when the shield cup is loosened or if tip
touches electrode inside the nozzle. Incorrectly installed or
improperly grounded equipment is a hazard.
Do not touch live electrical parts.
Wear dry, hole-free insulating gloves and body protection.
Insulate yourself from work and ground using dry insulating
mats or covers big enough to prevent any physical contact
with work or ground.
Do not touch torch parts if in contact with the work or ground.
Turn off power before checking, cleaning, or changing torch parts.
Disconnect input power before servicing this equipment.
Lockout/tagout input power according to OSHA CFR
1910.147
Properly install and ground this equipment according to the
Owner’s Manual and national, state, and local codes.
Check and be sure that input power cord ground wire is
properly connected to ground terminal in disconnect box or
that cord plug is connected to properly grounded receptacle
outlet-always verify the supply ground.
When making input connections, attach proper grounding
conductor first.
Frequently inspect input power cord, plasma torch and ground
cable for damage or bare wiring. Replace cord immediately if
damaged. Bare wiring can kill.
Turn off all equipment when not in use.
Do not wrap torch cable around your body.
Ground the work piece to a good electrical (earth) ground if
required by codes.
Use only well-maintained equipment. Repair or replace
damaged parts at once.
Wear a safety harness if working above floor level.
Keep all panels and covers securely in place.
Do not bypass or try to defeat the safety interlock systems.
Use only the Plasma Torch specified in the Owner’s Manual.
Keep away from torch tip and pilot arc when the plasma torch
trigger is pressed.
Clamp work cable with good metal-to-metal contact to work
piece (not piece that will fall away) or worktable as near the
cut as practical.
Insulate work clamp when not connected to work piece to
prevent contact with any metal object.
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4

Turn Off unit, disconnect input power, check voltage on input
capacitors, and be sure it is near zero (0) volts before
touching any parts. Check capacitors according to
instructions in Maintenance Section of Owner’s Manual or
Technical Manual before touching any parts.
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On inverter power sources, failed parts can
explode or cause other parts to explode
when power is applied. Always wear a face
shield and long sleeves when servicing inverters.
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Sparks and hot metal blow out from the cutting arc.
Chipping and grinding cause flying metal.
Wear approved face shield or safety goggles with side shields.
Wear proper body protection to protect skin.
Wear flame-resistant ear plugs or ear muffs to prevent sparks
from entering ears.
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Arc rays from the cutting process produce intense
visible an invisible (ultraviolet and infrared) rays that
can burn eyes and skin.
Wear face protection (helmet or shield) with correct shade of
filter to protect your face and eyes when cutting or watching.
ANSI Z49.1 (see Safety Standards) suggests No. 9 shade
(with No. 8 as minimum) for all cutting currents less than 300
amperes. Z49.1 adds that lighter filter shades may be used
when the arc is hidden by the work piece. As this is normally
the case with low current cutting, the shades suggested in
Table 1 are provided for the operator’s convenience.
Wear approved safety glasses with side shields under your
helmet or shield.
Use protective screens or barriers to protect other form flash
and glare; warn others not to watch the arc.
Wear protective clothing made from durable, flame-resistant
material (leather and wool) and foot protection.
Table 1. Eye Protection for Plasma Arc Cutting
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Cutting produces fumes and gases. Breathing these
fumes and gases can be hazardous to your health.
Keep your head out of the fumes. Do not breathe the fumes.
If inside, ventilate the area and/or use exhaust at the arc to
remove cutting fumes and gases.
If ventilation is poor, use an approved air-supplied respirator.
Read the Material Safety Data Sheet (MSDS) and the
manufacturer’s instruction for metals to be cut, coating, and
cleaners.
Work in a confined space only if it is well ventilated, or while
wearing an air-supplied respirator. Fumes from cutting and
oxygen depletion can alter air quality causing injury or death.
Be sure the breathing air is safe.
Do not cut in locations near degreasing, cleaning, or spraying
operations. The heat and rays of the arc can react with vapors
to form highly toxic and irritating gases.
Do not cut on coated metals, such as galvanized, lead, or
cadmium plated steel, unless the coating is removed from the
cutting area, the area is well ventilated, and if necessary,
while wearing an air supplied respirator. The coatings and any
metals containing these elements can give off toxic fumes
when cut.
Do not cut containers with toxic or reactive materials inside
or containers that have held toxic or reactive material-they
must be emptied and properly cleaned first.
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The heat from the plasma arc can cause serious burns.
The force of the arc adds greatly to the burn hazard.
The intensely hot and powerful arc can quickly cut
through gloves and tissue.
Keep away from the torch tip.
Do not grip material near the cutting path.
The pilot arc can cause burns-keep away from torch tip when
trigger is pressed.
Wear proper flame-retardant clothing covering all exposed
body areas.
Point torch away from your body and toward work when
pressing the trigger. Caution - pilot arc comes on immediately.
Turn off power source and disconnect input power before
disassembling torch or changing torch parts.
Use only the plasma torch specified in the Owner’s Manual.
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Gas cylinders contain gas under high pressure. If
damaged, a cylinder can explode. Since gas cylinders
are normally part of metalworking processes, be sure
to treat them carefully.
Protect compressed gas cylinders from excessive heat,
mechanical shocks, slag, open flame, sparks, and arcs.
Install and secure cylinders in an upright position by chaining
them to a stationary support or equipment cylinder rack to
prevent falling or tipping.
Keep cylinders away from any cutting or other electrical circuits.
5

Safety and Health Standards, OSHA 29 CFR 1910, from
Superintendent of Documents, U.S. government Printing Office,
Washington, D.C. 20402.
Recommended Practices for Plasma Arc Cutting, American
Welding Society Standard AWS C5.2 from American Welding
Society, 550 N.W. LeJeune Rd, Miami, FL 33126
National Electrical Code, NFPA Standard 70, from National
Fire Protection Association, Batterymarch Park, Quincy, MA
02269
Safe Handling of Compressed Gases in Cylinders, CGA
Pamphlet P-1, from Compressed Gas Association, 1235
Jefferson Davis Highway, Suite 501, Arlington, VA 22202
Code for Safety in Welding and Cutting, CSA standard W117.2
from Canadian Standards Association, Standards Sales, 178
Rexdale Boulevard, Rexdale, Ontario, Canada M9W 1R3.
Safe Practices for Occupation and Educational Eye and Face
Protection, ANSI Standard Z87.1, from American National
Standards Institute, 1430 Broadway, New York, NY 10018
Cutting and Welding Processes, NFPA Standard 51B, from
National Fire Protection Association, Batteymarch Park, Quincy,
MA 02269.
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Considerations about Welding or Cutting and the Effects of Low
Frequency Electric and Magnetic Fields.
Welding or cutting current, as it flows through the welding or
cutting tables, will cause electromagnetic fields. There has been
and still is some concern about such fields. However, after
examining more than 500 studies spanning 17 years of research,
a special blue ribbon committee of the Nation Research
Council concluded that: “The body of evidence, in the
committee’s judgment, has not demonstrated that exposure to
power-frequency electric and magnetic fields is a human health
hazard.” However studies are still going forth and evidence
continues to be examined. Until the final conclusions of the
research are reached, you may wish to minimize your exposure
to electromagnetic fields when welding or cutting.
To reduce magnetic fields in the work place, use the following
procedures:
1. Keep cables close together by twisting or taping them.
2. Arrange cables to one side and away from the operator.
3. Do not coil or drape cables around your body.
4. Keep cutting power source and cables as far away from
operator as practical.
5. Connect work clamp to work piece as close to the cut as
possible.
About Pacemakers:
Pacemaker wearers consult your doctor first. If cleared by your
doctor, then following the above procedures is recommended.
Never allow electrical contact between a plasma arc torch
and cylinder.
Never cut on a pressurized cylinder. Explosion will result.
Keep protective cap in place over valve except when cylinder
is in use or connected for use.
Read and follow instructions on compressed gas cylinders,
associated equipment, and CGA publication P-1 listed in
Safety Standards.
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Do not touch hot parts bare handed.
Allow a cooling period before disassembling the plasma torch.
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Wear safety glasses with side shields or face shield.
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Pacemaker wearers keep away.
Wearers should consult their doctor before going near
plasma arc cutting operations.
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Allow cooling period; follow rated duty cycle.
Reduce amperage (thickness) or reduce duty cycle
before staring to cut again.
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When cutting aluminum underwater or with the
water touching the underside of the aluminum, free
hydrogen gas may collect under the work piece.
See your cutting engineer and water table instructions for
help.
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Electromagnetic energy can interfere with sensitive
electronic equipment such as computers and computer-
driven equipment such as robots.
To reduce possible interference, keep cables as short as
possible, close together, and down low, such as on the floor.
Locate cutting operation 300 feet from any sensitive
electronic equipment.
Be sure this cutting power source is installed and grounded
according to manual.
If interference still occurs, the user must take extra measures
such as moving the machine, using shielded cables, using
line filter, or shielding the work area.
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Safety in Welding and Cutting, ANSI standard A49.1 from
American Welding Society, 550 N.W. LeJuene Rd, Miami FL 33126
6

Inspection
After removing your plasma cutter from its shipping carton,
inspect the plasma cutter for any concealed damage not seen
upon receiving the unit. Any claims for loss or damage
occurring during shipping must be filed by the purchaser with
the freight company.
Check the inlet air supply at the rear of the cabinet to be sure no
packing materials have gotten inside to obstruct the air flow to
the plasma torch.
Plasma/Cooling Gas Connection
Your Micro Cut 875S has been designed to use clean, dry
compressed air as both the plasma and cooling gas. Water
and/or oil in the air will significantly reduce the life of the
electrode and the cutting nozzle, at the same time reducing the
quality of the cut.
Safety sensing circuitry has been installed to eliminate arc-
initiation if the pressure and volume are inadequate. The filter
regulator is mounted on the back of your Micro Cut 875S. The
inlet to the regulator is a standard 1/4” NPT female thread.
Install a quick disconnect fitting which is compatible with your
air line in the regulator.
Plasma/Cooling Gas Pressure Volume
70 psi 3.2 cfm
To correctly set the air pressure, depress the purge button on the
front of your Micro Cut 875S. While the air is flowing, lift up
on the regulator adjusting knob, and set the air pressure to 70
psi. Push the regulator adjusting knob down to lock when
finished.
Damage to your plasma cutter due to excessive water and/or oil
in the air supply line is not covered under warranty. Your Micro
Cut 875S comes equipped with a regulator/filter. In addition,
HTP has 2 filters available for removing any impurities from the
air. If you already have a drier on your compressor, we
recommend the HTP Super Dry (Part # 25300) which is a
disposable in-line filter. This filter uses a desiccant to
completely remove all moisture from the air. The desiccant is
blue when new and turns clear when the filter needs to be
discarded.
If you do not have a drier on your compressor, we strongly
recommend the HTP Max Dry (Part # 25310). This is a 3 stage
filter which
completely removes
all oil and water
from the air. The
first stage of the
Max Dry removes
the water which is
present in the air.
The second stage of
the filter removes
any oil which may
be in the air along
with particulate down to .03 microns. The final stage is the
desiccant drier, which removes the humidity from the air. The
desiccant in the final stage is reusable. It is blue when it is
fresh, and changes to pink when it has absorbed moisture. Just
put the pink desiccant in the oven to bake the moisture out and
reuse. This filter extends the life of your air tools and is great
for painting also.
WARNING: Check the air regulator set every day for
proper pressure, volume and water/oil levels.
Electrical Connection
All electrical connections should be performed by a qualified
electrician in accordance with the National Electrical Code and
local codes and ordinances. When connecting your plasma
cutter, the yellow-green wire MUST BE CONNECTED TO
GROUND, OR SERIOUS INJURY OR DEATH MAY
RESULT!
ELECTRICAL SHOCK CAN KILL! Do not connect an
input wire to the ground terminal. Do not connect the ground
(yellow-green or green) wire to an input (hot) line terminal.
It is also strongly recommended that a fusible line disconnect
switch be installed in the input power circuit to the plasma
machine. This would provide a safe and easy method to remove
all electrical power from your plasma system whenever it is
necessary to perform internal inspection or servicing.
BEFORE ATTEMPTING TO MAKE ANY PRIMARY POWER
CONNECTIONS TO YOUR PLASMA CUTTER, BE SURE
THAT ALL POWER IS OFF BY OPENING THE LINE
DISCONNECT SWITCH.
Your MicroCut 875S has been designed to operate from 220 volt
single phase power wired for a minimum of 42 amps. The green
or yellow-green wire must be connected to ground. The blue
and brown wires must be connected to the hot legs of the 220-
volt power.
7
Fig.1
#25300
HTP Super Dry
Fig.2 #25300
HTP Super Dry

8
1
5
2
3
11
7
6
8
9
4
10
FRONT PANEL COMNTROLS
1) Input Power Light
2) Air Pressure Light
3) Thermo Switch Light
4) Safety Alarm
5) Cutting Power Adjustment
6) Reset Switch
7) Gas Purge Switch
8) Main Power Switch
9) Expanded Metal Switch
10) Plasma Torch Connection
11) Ground Cable Connection
Fig. 3
Micro Cut 875S Controls
1) INPUT POWER LIGHT - when the machine
is correctly connected to a 220 volt input power
supply, and the Main Power Switch (#8) is turned
on, a green light will be illuminated, indicating your
Micro Cut 875S is connected to the correct power
supply.
2) AIR PRESSURE LIGHT - when the machine
is correctly connected to an air supply and the
regulator adjusted so the air pressure gauge reads
above 40 psi, the green air pressure light will be
illuminated. If the pressure falls below 40 psi, the
green air pressure light will go out, and the Safety
Alarm light will turn red.
It is important that the air pressure is set to 70 psi for
the correct operation of the machine with the air
pressure flowing.
3) THERMO SWITCH LIGHT - if the duty
cycle of the machine is exceeded (40% at 60 amps)
the yellow thermo switch light will be illuminated. If
this happens, leave the machine on so the cooling fan
will continue to run, cooling the machine. When the
machine has cooled down, the yellow light will go
out.
4) SAFETY ALARM LIGHT - this lamp will
illuminate red when the machine is first turned on.
Pressing the reset button (# 6) turns the red Safety
Alarm light off. If the red trouble light remains on,
either the plasma torch is not installed correctly on
the machine, the consumable parts are not installed
correctly on the plasma torch or the air pressure is
below 40 psi.
5) CUTTING POWER ADJUSTMENT - the
cutting power adjustment controls the cutting
amperage of your Micro Cut 875S. It is infinitely
variable from 30 to 55 amps. At the lower power
settings, the machine will throw fewer sparks - but
will also cut slower. The maximum cutting power
will give you the maximum cutting speed through all
materials.

9
You can do drag cutting (resting the plasma torch on
the work) when the amperage is set to 40 amps or
less with the deflector and the 40 amp tip installed in
the machine. For drag cutting over 40 amps, the drag
shield cap and 60 amp cutting tip should be used.
6) RESET SWITCH - when the machine is
turned on for the first time, the red trouble light will
be illuminated. If the machine is connected to the
correct power source, the correct air supply, and the
torch is installed correctly; depressing the reset
button will turn off the red trouble light and allow
you to begin cutting.
7) GAS PURGE SWITCH - the gas purge
switch allows you to purge air through the torch,
allows you to manually cool the cutting torch after
long periods of cutting, and allows you to set the air
pressure while the air is flowing through the plasma
torch.
To purge the torch, simply press the gas purge
button. Air will start to flow. The air will stop
flowing automatically.
8) MAIN POWER SWITCH – Turning the main
power switch will supply 230 volt power to your
Micro Cut 875S. When you are finished operating
the machine, turn the power switch off.
9) MANUAL/AUTOMATIC CUTTING
SWITCH - The manual/automatic selection switch
allows you to select between manual cutting and
automatic cutting. In the manual mode, when the
plasma arc loses contact with the material being cut,
the arc will extinguish. To reestablish the arc, the
trigger must be released and then depressed. The arc
will then ignite. Manual cutting is designated by the
solid line, or the upper switch position.
In the Automatic Cutting mode, the machine will
automatically re-start the arc if contact is lost with
the metal. This setting is good if you are trying to cut
expanded metal. The Automatic mode is designated
by the dashed line, or the lower position.
We recommend leaving the machine in the manual
setting unless there is some need to have the arc
automatically ignite once contact is lost with the
metal.
10) PLASMA TORCH CONNECTION - the
central adapter block is where the plasma torch
connects to the front of your Micro Cut 875S. Your
machine will not operate without the torch properly
connected. (see page 5 - plasma torch connection)
11) GROUND CABLE CONNECTION - this is
where the ground cable connects to the front of your
Micro Cut 875S. Align the tab on the ground clamp
with the notch in the connection. Insert the ground
clamp and twist to lock in place. Be sure to connect
the ground clamp to a clean freshly ground off spot
on the work piece.
Ground Cable Connection
Assemble the ground cable as shown in Figure 3. The ground
cable is connected to the front (See Fig 3, #11) of the machine.
Plug the cable into the receptacle and twist clockwise until
tight.
Connect the ground clamp as close to the workpiece as
possible. This will reduce the possibility of current loss
through stray paths. Always connect the clamp to clean, bare
metal. Do not connect the ground clamp to the piece which
will be cut off.
Plasma Torch Connection
Disconnect power from the machine. The plasma cutting torch
on your Micro Cut 875S is a quick-disconnect design, allowing
you to easily remove and install the cutting torch without any
tools. This makes it very easy to transport your machine or
service the cutting torch.
To install the cutting torch, insert the copper plug into the center
of the adapter block mounted on the front of the plasma cutter.
(See Fig 3, #10)Rotate the plasma torch until the male plastic
tab on the plasma torch fits into the cutout on the bottom of the
adapter block. Firmly push the plasma torch into the adapter
block and secure it by tightening the adapter nut until snug.

10
Operation
1. Be sure your Micro Cut 875S is connected to a clean, dry
source of compressed air with a line pressure of at least 80
but not more than 140 psi.
2. Connect your Micro Cut 875S to a 230 volt power supply.
(see electrical connection). Turn the On-Off switch on. The
green 230 V light and the green air pressure light will turn on.
The fan will begin to run. The red trouble light will be on.
Press the reset switch to turn the trouble light off.
3. Refer to the safety suggestions to be sure the operator has
the correct eye protection, gloves, clothing, and that all of the
safety precautions have been followed.
4. Place the cutting torch on the edge of the material to be
cut. Depress the trigger on the cutting torch. Pre-air flowwill
occur for about 1/2 second. The pilot arc will start
immediately after that. Once themain arc is established,
KEEPTHE PLASMA TORCH IN CONTACT WITH THE
WORKPIECE if you are using the drag cutting tip. Adjust
the cutting speed based on the thickness and type of material
you are cutting. Hold the plasma torch perpendicular to the
work. Move the plasma torch at a speed which keeps the
plasma arc bent anywhere from 5 to 15 degrees. (See Fig 4).
When you release the trigger, the arc will stop, but air will
continue to flow for about 30 seconds to cool the plasma
torch. When using the drag cutting tip, the highest cutting
efficiency is achieved by keeping the plasma cutting tip
perpendicular and in contact with the work surface putting
very little downforce on the plasma torch. If you move too
fast, sparks will shoot up and you will not cut all the way
through the work. If you are cutting correctly all the plasma
sparks will go beneath the panel you are cutting.
Fig. 4
5. When piercing a thicker sheet of steel (1/4” and greater)
hold the torch at approximately a 45 degree angle and
gradually roll the torch until it is perpendicular to the work
piece (See Fig. 5) If the torch is held perpendicular to the
work to start, there will be no where for the slag to flow, and it
will come straight up and damage the gas diffuser, cutting tip,
and electrode.
Fig. 5
WARNING: Never disassemble the cutting torch unless the
machine has been disconnected from its power supply.
Maintenance and Service
Always disconnect the machine from the main power source
before performing any maintenance or service work.
Consumable Parts:
1. Check nozzle and electrode often for excessive wear due to
cutting. The electrode will develop a pit in the center of it. When
the pit reaches approximately 1/16" deep, the electrode should
be replaced. (See Fig. 6)
Fig. 6
Likewise, when the hole in the center of the cutting tip becomes
enlarged to approximately 1/16" in diameter, the cutting
efficiency will be reduced and the cutting tip should be
replaced. (See Fig. 7)

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Fig. 7
2. Clean exposed torch consumables often. This will maintain
their life.
3. Check nozzle and electrode often for proper installation.
4. Frequently check the air supply quality. This is the single
most important factor in the maintenance of the plasma system.
After Each Use:
1. Check the cutting tip, electrode, and shield cap for wear.
2. Make sure the air is set to 70 psi while it is flowing.
Every Week
1. Check the parts in place safety circuit to make sure it is
working
Every 3 Months
1. Remove the side panels and blow the dust out of the machine
with compressed air.
2. Replace any cracked parts.
3. Check the torch handle for cracks and replace if necessary.
4. Frequently check the air supply quality. This is the single
most important factor in the maintenance of the plasma system.
5. If any damage to the machine or torch is noticed, contact
your local distributor or HTP America, Inc. directly at 1-800-USA-
WELD.
IF ANY SERVICE OTHER THAN THE AFOREMENTIONED
IS NECESSARY, IT SHOULD BE PERFORMED BY
AUTHORIZED PERSONNEL ONLY.
Cutting Tips
1. When making long, straight cuts, it may be easier to use a
metal straight edge as a guide. Simply clamp it to the work
piece to be cut. HTP America, Inc. also manufactures a
complete Circle-Cutting and Straight-Line Traversing Assembly
for frequent cutting of circles and lines.
Fig. 8 Circle Cutting Attachement
2. When cutting heavier gauge material (up to the machine
capability) it is recommended to initiate the pilot arc off the
edge of the material and dragging the pilot arc to the work piece.
3. When making rust repairs, it is possible to place the new
metal over the rusted area and then cut your patch panel at the
same time you cut the rust. This process works similarly when
splicing a quarter panel.
4. Please note that sparks from cutting arcs can damage painted
surfaces. The sparks will also pit glass. We recommend the use
of a welding blanket to protect these surfaces.
5. The best cutting speed is achieved when the plasma arc
penetrates the work piece at an angle of 5-15 degrees. The
cutting speed is dependent on material thickness and
composition as well as operator proficiency.
6. Never turn the machine off immediately after cutting. Always
allow the post air flow circuitry to run its complete cycle to
ensure proper cooling of the torch head.
7. It is highly recommended that piercing requirements be kept
to a maximum of 75% of rated cutting thickness. This will
greatly enhance the plasma torch's consumable life. When
piercing thick pieces of metal, it is best to hold the cutting torch
at a 45 degree angle to the work until the plasma arc has pierced
the material. Holding the torch perpendicular to the work will
result in sparks and slag firing back up into the plasma torch,
greatly reducing consumable life.

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MicroCut 875S Torch Parts Breakdown
Ref # Description Part #
1 Shield Cap - Drag Cutting 87005D
1A Shield Cap - Stand Off 87005SO
Shield Cap - Gouging 87005G
2 Safety Cup 87005
Ref # Description Part #
3 Cutting Tip - 60 Amp 870030-60
Cutting Tip - 40 Amp 870030-40
Cutting Tip - Wide 870030-W
Cutting Tip - Medium 870030-M
4 Start Cartridge 87058
5 Electrode 87003
Cutting Speed Chart
MicroCut 875S 40 amps
HTP MICROCUT 875S SPECIFICATIONS:
Primary Voltage . . . . . . . . . . . . . . . . . . 230 volts
Primary Amperage . . . . . . . . . . . . . . . . 40 amps
Cutting Current. . . . . . . . . . . . . . . . . . . 30 to 55 amps
Infinitely Variable
Open Circuit Voltage . . . . . . . . . . . . . . 320 Volts DC
Duty Cycle . . . . . . . . . . . . . . . . . . . . . . 40% @ 55 amps
100% @ 45 amps
Cutting Voltage . . . . . . . . . . . . . . . . . . 102 VDC @ 55 amps
96 VDC @ 45 Amps
Quality Cutting Capacity . . . . . . . . . . . _” @ 7 _”/min
Severance Cutting Capacity . . . . . . . . 1 1/8” @ 3”/min
Weight. . . . . . . . . . . . . . . . . . . . . . . . . . 40 lbs.
Dimensions . . . . . . . . . . . . . . . . . . . . . . 22” L x 8” W x 11 1/2” H
Cutting Torch Length . . . . . . . . . . . . . . 20ft.
Ground Cable Length . . . . . . . . . . . . . . 10 ft.
Input power cord length . . . . . . . . . . . . 12 ft.
Plasma/Cooling Gas Pressure. . . . . . . . 70 psi
Plasma/Cooling Gas Volume . . . . . . . . 3.2 cfm

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Part # Illus # Description
66109 1 Handle
62019 3 Top Cover
66231 4 Knob - On-Off Switch
64188 5 Manual/Auto Switch
660554 6 ID Label
660555 7 Torch - Ground Label
20320 8 Female Ground Receptacle
22312 Male Ground Plug
22310 Ground Clamp Complete
61471 9 Female Torch Receptacle
660556 17 Decal - Side Panel
62020 18 Side Panel
66028 19 Knob - Amperage
660553 38 Front Panel Label
MicroCut 875S Parts Breakdown part 1

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Part # Illus # Description
610889 10 PCB - Primary Power
64393 11 Gas Solenoid Valve
64032 12 Pressure Safety Switch
650193 13 Control Transformer
64180 14 Fuse Holder
203335-2 15 Fuse
MicroCut 875S Parts Breakdown part 2

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Part # Illus # Description
611124 20 PCB - Front Panel
61307 27 Choke Coil
66160 28 Gas Hose
61733 29 PCB - Input Power
62018 30 Cabinet - Base
64215 31 Thermoswitch - 70°C
63053 32 Pressure Guage
63055 33 Regulator
64132 34 MicroSwitch - Safety
62639 35 Center Panel
62022 36 Regulator Bracket
MicroCut 875S Parts Breakdown part 3

Part # Illus # Description
64182 21 Cooling Fan
610784 22 SPCB - Secondary Powe
65775 23 Thermoswitch - 80°C
610833 24 PCB - Pilot Switchover
62572 25 Front Panel
64154 26 On-Off Switch
MicroCut 875S Parts Breakdown part 4
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17
MicroCut 875S Wiring Diagram

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