INSTRUCTIONS for
PT-20AM
MECHANIZED PLASMA ARC CUTTING TORCH
Without Rack, 50-ft., Unshielded..................................P/N 21360
With Rack, Torch Holder, 50-ft., Shielded ....................P/N 21371
With Rack, 50-ft., Shielded...........................................P/N 22057
Without Rack, 50-ft., Shielded......................................P/N 21977
Without Rack, 4-1/2-ft., Shielded...................................P/N 21785*
Without Rack, 17-ft., Shielded.......................................P/N 21786*
* For connecting to plumbing boxes.
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles of operation and safe
practices for arc welding equipment, we urge you to read out booklet, "Precautions and Safe Practices for Arc Welding,
Cutting and Gouging", Form 52-529. Do NOT permit untrained persons to install, operate, or maintain the equipment. Do
NOT attempt to install or operate this equipment until you have read and fully understand these instructions. If you do not
fully understand these instructions, contact your supplier for further information.
torch with minimum downtime (see Table 1 for contents of
each kit):
The plasma arc cutting process employs extremely high
voltages and contact with "live" parts of the torch and
machine must be avoided. Also, the improper use of any
of the gases employed can present a safety hazard. Before
beginning operation with the PT-20AM torch, refer to the
safety precautions listed on page 2 of instruction booklet
packed with your plasma cutting console.
I. INTRODUCTION
The patented PT-20AM is a 100 amp capacity, pilot-arc
mechanized torch (see Fig. 1) available in 6 different versions
listed above. The torch uses clean, dry air as the cut gas for
cutting carbon steel, aluminum, or stainless steel. DO NOT
use oxygen; a hazardous fire may result.
This booklet covers mainly the accessories, maintenance,
and parts information for the PT-20AM torch. For installation
and operating instructions for your cutting package, refer to
appropriate booklet with your console.
II. ACCESSORIES
A. PT-20AM Torch Spare Parts Kits - The following three
spare parts kits are available for maintaining the PT-20AM
50 Amps - P/N 21370
70 Amps - P/N 21369
100 Amps - P/N 21376
Table 1 - Contents of PT-20AM Spare Parts Kits
50 Amp 70 Amp 100 Amp
Description, P/N 21370 21369 21376
Heat Shield (70/100 A), 21326 - 2` 2
Heat Shield (50 A), 21447 2 1 1
Cutting Nozzle (50 A), 21330 5 5 5
Cutting Nozzle (70 A), 21329 - 5 5
Cutting Nozzle (100 A), 21328 - - 5
Electrode, 21150 5 5 5
Electrode**, 0558001617 5** 5** 5**
Electrode Insulator, 21373 1 1 1
Electrode Holder Assy, 21332 1 1 1
Baffle Tube, 21374 1 1 1
Pilot Arc Adaptor, 19497 1 1 1
O-ring, 488157 5 5 5
Lubricant (1 oz.), 17672 1 1 1
Seat/Baffle Wrench, 21375 1 1 1
1/16: Hex-Key Wrench,
93750006 1 1 1
Tool Box, 950272 1 1 1
**For 50Hz Machines
F-15-114-E
January, 2001
Quantity
7 5/8" min. - 14 1/2" max.
5/8" Mounting Stud
17 1/2" With Rack
1 3/8" Dia.
Fig. 1 - Dimensional Data - PT-20AM
Be sure this information reaches the operator.
You can get extra copies through your supplier.
1 3/8" Dia.
13 1/2" Without Rack
III. INSTALLING FRONT END PARTS
Make sure power switch on console is in OFF position and
primary input power is deenergized.
1. The electrode holder assembly (21332) includes the baffle
tube (21374). If the baffle tube becomes damaged, it can be
replaced by threading the damaged tube out of the holder
and threading in the new one. Use the small hex end of the
wrench (21375) in the hex broach on the tube. Tighten the
tube securely but do not overtighten.
2. Install the electrode insulator (21373) onto the electrode
holder assembly (21332) and then thread the electrode
(21150) onto the electrode holder assembly. Assemble the
electrode firmly by hand. Do not use wrenches or pliers.
These three parts together are the electrode assembly.
3. Install the nozzle onto the electrode assembly by inserting
the small shoulder on the electrode insulator into the
nozzle’s rear opening. Place the nozzle and electrode
assembly into the heat shield as shown in Fig 2. If the front
end of the torch is facing down as normally in a setup, the
nozzle and electrode assembly can be stacked in the heat
shield and then assembled to the torch. Be sure to use the
proper heat shield and nozzle combination as noted in Fig.
2.
NOTE:
These parts are NOT interchangeable with origninal PT-20M
Torch. P/Ns 20598 and 20599 are covered by F-15-021.
BAFFLE TUBE - 21374
WRENCH SEAT/
BAFFLE - 21375
4. Apply a thin film of lubricant (17672) to O-ring (488157).
5. Tighten heat shield fully to hold the parts in firm contact with
each other and to the torch head.
IMPORTANT: See Maintenance section.
Follow all instructions in the booklet packed with your unit. DO
NOT install or attempt to operate this torch without following
these instructions.
To connect PT-20AM torch to the console, connect the power
cable of the torch to the ‘‘NEG’’ terminal and pilot arc cable to
the ‘‘POS’’ terminal of the unit using pilot arc adaptor (19497
- supplied with spare parts kit). A separate remote control
switch cable is required for connecting to the switch receptacle
on the console.
The front end of the torch contains a gas flow check valve that
acts in conjunction with the circuitry provided in the power
supply. This patented system provides a safety interlock
preventing the torch from being accidentally energized with
high voltage when the heat shield is removed and the torch
switch is accidentally closed.
NOTE:
Torch body insulator design was changed to eliminate the
need for a replaceable electrode seat. This drawing and parts
list reflects that change. The insulator material color was
changed for indentification of the part revision level.
Brown torch body insulators were used on torches
before 12/99 and do require a separate electrode seat.
Gray torch body insulators indicate there is not a replaceable
electrode seat...
DO NOT ATTEMPT TO REMOVE THE ELECTRODE SEAT
FROM THESE TORCHES AS EQUIPMENT DAMAGE WILL
OCCUR.
ELECTRODE INSULATOR - 21373
ELECTRODE - 21150
ELECTRODE-50Hz - 0558001617
ELECTRODE ASSEMBLY
ELECTRODE HOLDER ASSEMBLY - 21332
(INCLUDES BAFFLE TUBE - 21374)
NOZZLE
100 AMP - 21328
70 AMP - 21329
HEAT SHIELD
70 & 100A (Blue) - 21326
50 Amp (White) - 21447
50 AMP - 21330
Fig. 2 - Front End Assembly
2
TORCH BODY INSULATOR
(Reference,
not replaceable)
O-RING - 488157
CUTTING PARAMETERS FOR THE PT-20AM TORCH
ON CARBON STEEL
Table 2: 100 Amp Data, Nozzle P/N 21328, Heat Shield P/N 21326
Metal
Thickness
(in.) (mm)
0.250 6
0.500 13
0.750 19
1.000 25
1.250 32
1.500 38
Metal
Thickness
(in.) (mm)
0.125 3
0.250 6
0.500 13
0.750 19
1.000 25
1.250 32
Air
Pressure
(psig) (bar)
85 6
85 6
85 6
85 6
85 6
85 6
Stand-off
(in.) (mm)
0.250 6
0.250 6
0.250 6
0.250 6
0.312 8
0.312 8
Arc
Voltage
DC Volts
110
120
125
130
140
145
Pierce
Time
(sec.)
0.1
0.3
1.0
2.75
*N.R.
*N.R.
M ild Ste el
(ipm) (mm/min)
100 2540
45 1143
27 686
15 381
10 254
7 178
Trave l Speed
Aluminum
(ipm) (mm/min)
105 2667
50 1270
35 889
20 508
13 330
10 254
Table 3: 70 Amp Data, Nozzle P/N 21329, Heat Shield P/N 21326
Air
Pre ssure
(psig) (bar)
75 5
75 5
85 6
85 6
85 6
85 6
Stand-off
(in.) (mm)
0.188 5
0.188 5
0.250 6
0.250 6
0.312 8
0.312 8
Arc
Voltage
DC Volts
105
110
115
130
140
155
Pierce
Time
(sec.)
0.1
0.2
0.6
2.3
*NR
*NR
Mild Steel
(ipm) (mm/min)
190 4826
80 2032
30 762
15 381
7 178
5 127
Travel Spee d
Aluminum
(ipm) (mm/min)
180 4572
85 2159
30 762
25 635
12 305
10 254
Stainless
(ipm) (mm/min)
80 2032
30 762
15 381
10 254
7 178
5 127
Stainless
(i pm) ( mm/ mi n)
80 2032
55 762
20 381
8 254
6 152
3 76
Table 4: 40 & 50 Amp Data, Nozzle P/N 21330, Heat Shield P/N 21447
Metal
Thickness
(in.) (mm)
0.063 2
0.125 3
0.188 5
0.250 6
0.375 10
0.500 13
* NR - Indicates piercing is not recommended.
Air
Pressure
(psig ) (bar)
75 5
75 5
85 6
85 6
85 6
85 6
Stand-off
(in.) (mm)
0.125 3
0.125 3
0.125 3
0.188 5
0.250 6
0.312 8
Arc
Voltage
DC Volts
110
110
110
120
130
150
Curr ent
Amp s
3
Arc
40
40
50
50
50
50
Mild Steel
(ipm) (mm/min)
150 3810
100 2540
100 2540
65 1651
40 1016
18 457
Travel Speed
Alumin um
(ipm) (mm/min)
150 3810
105 2667
90 2286
75 1905
30 762
8 2034
Stainless
(ipm) (mm/min)
130 3302
75 1905
50 1270
30 762
8 203
6 76
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