INSTRUCTIONS for
PHC-402
CUTTING POWER SUPPLY
NOTE: Refer to local code requirements for correct plasma
cutting output cables. Do not use ordinary welding cable.
F-14-260
April, 1984
SPECIFICATIONS
Rated
Output
Output Current Range 100-500 Amps
Open Circuit Voltage 415 Volts DC
Input Voltage
Input Current
@
Rated Output
Power Factor @ Rated Load 0.85%
Dimensions
Weight 1830 l bs.-830 kg.
*This 100% Duty is based on a cycle in which the fans are cooling,
with no load, for 30 minutes maximum, see Section I-B.
Continuous Duty 400 Amp @ 215 Volts D C
100% Duty - 1/2 Hr.* 500 Amp @ 180 Volts D C
460 VAC, 60 Hz, 3-Ph
380 VAC, 50 Hz, 3-Ph
415 VAC, 50 Hz, 3-Ph
400 Amp
Output
500 Amp
Output
Width
Depth
Height
130 Amp @ 460 VAC, 60 Hz
144 Amp @ 415 VAC, 50 Hz
158 Amp @ 380 VAC, 50 Hz
163 Amp @ 460 VAC, 60 Hz
180 Amp @ 415 VAC, 50 Hz
198 Amp @ 380 VAC, 50 Hz
36.75 inches - 933.5 mm
43.50 inches - 1105 mm
31 inches - 787.4 mm
These INSTRUCTIONS are for experienced operators. Do NOT use with any process other than plasma cutting.
This unit has a high voltage output designed for plasma cutting only. If you are not fully familiar with the principles
of operation and safe practices for electric welding equipment, we urge you to read ESAB's free booklet, "Precautions and Safe Practices for Electric Welding and Cutting, " Form 52-529. Do not permit untrained persons to
install, operate, or maintain this 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. Be sure to read the Safety Precautions on page 2 before installing or operating this equipment.
I. INTRODUCTION
solid state circuitry. The unit can be operated in a single, fully
balanced output current range from 100 to 500 amps. A current
The PHC-402 Power Supply (P/N 679500) is designed for high
speed plasma arc cutting applications. When used with suitable plasma arc cutting equipment, such as ESAB's mechanized PCM-500 outfit (covered in Form 14-255), it is sufficiently
control Panel-Remote Switch determines the location from
which the output current will be regulated; either locally from
the power supply front panel ("Panel" position) or remotely
from the control assembly ("Remote" position).
powered to provide high quality cuts in all types of commercial
metals. If greater cutting current capability is required, parallel
operation of these units is permissible -- please consult with
the factory for instructions. For additional operating data and
electrical characteristics of this machine, refer to the Specification Table.
The PHC-402 is powered by a three-phase main transformer
which combines with solid state control to provide steep voltampere curve output characteristics required for plasma cutting. A three-phase full wave SCR and diode bridge rectifier is
used to convert the a.c. output current from the transformer to
d.c. cutting current, and also control the output current through
A. DESCRIPTION
The PHC-402 cutting power supply is a silicon controlled rec-
the SCR's. A network, of integrally-mounted capacitors and
resistors provide transient and high-frequency voltage pro-
tifier (SCR), three-phase transformer/rectifier type d.c. unit with
Be sure this information reaches the operator.
You can get extra copies through your supplier.
ESAB Welding &
Cutting Products
SAFETY PRECAUTIONS
WARNING: These Safety Precautions are for your protection. Before performing any installation or operating procedures, be sure to
read and follow the safety precautions listed below. Failure to observe these Safety Precautions can result in personal injury or death.
1. PERSONAL PROTECTION -- Skin and eye burns from exposure to
rays from an electric-arc or hot metal can be more severe than
sunburn. Therefore:
a. Use a face shield fitted with the correct filter and cover plates
to protect your eyes, face, neck, and ears from sparks and rays
of the arc when operating or observing operations. WARN bystanders not to watch the arc and not expose themselves to the
rays of the electric-arc or hot metal.
b. Wear flameproof gauntlet type gloves, heavy long-sleeve shirt,
cuffless trousers, high-toppered shoes, and a welding helmet
or cap for hair protection, to protect against arc rays and hot
sparks or hot metal. A flameproof apron may also be desirable
as protection against radiated heat and sparks.
c. Hot sparks or metal can lodge in rolled up sleeves, trouser cuffs,
or pockets. Sleeves and collars should be kept buttoned, and
pockets eliminated from the front of clothing.
d. Protect other nearby personnel from arc rays and hot sparks
with a suitable non-flammable partition.
e. Always wear safety glasses or goggles when in a work area.
Use safety glasses with side shields or goggles when chipping
slag or grinding. Chipped slag may be hot and can travel considerable distances. Bystanders should also wear safety glasses
or goggles.
f. Some gouging and cutting processes produce excessively high
noise levels and require ear protection.
2. FIRE PROTECTION -- Hot slag or sparks can cause serious fires
when in contact with combustible solids, liquids, or gases. Therefore:
a. Remove all combustible materials well away from the work area
or completely cover the materials with a protective non-flammable covering. Such combustible materials include wood,
clothing, sawdust, gasoline, kerosene, paints, solvents, natural gas, acetylene, propane, and similar combustible articles.
b. Hot sparks or hot metal can fall into cracks in floors or wall
openings and cause a hidden smoldering fire. Make certain
that such openings are protected from hot sparks and metal.
c. Do not weld, cut or perform other hot work until the workpiece
has been completely cleaned so that there are no substances
on the workpiece which might produce flammable or toxic vapors.
d. For fire protection, have fire extinguishing equipment handy
for instant use, such as a garden hose , water pail, sand bucket,
or portable fire extinguisher.
e. After completing operations, inspect the work area to make cer-
tain there are no hot sparks or hot metal which could cause a
fire later.
f. For additional information, refer to NFPA Standard 51B, "Fire
Prevention in Use of Cutting and Welding Processes", which is
available from the National Fire Protection Association,
Batterymarch Park, Quincy, MA 02269.
3. ELECTRICAL SHOCK -- Contact with live electrical parts can cause
severe burns to the body or fatal shock. Severity of electrical shock
is determined by the path and amount of current through the body.
Therefore:
a. Never allow live metal parts to touch bare skin or any wet cloth-
ing. Be sure gloves are dry.
b. When standing on metal or operating in a damp area, make cer-
tain that you are well insulated. Wear dry gloves and rubbersoled shoes and stand on a dry board or platform.
c. Always ground the power supply by connecting a ground wire
between the power supply and an approved electrical ground.
d. Do not use worn or damaged cables. Do not overload the cable.
Use well maintained equipment.
e. When not operating, turn off the equipment. Accidental ground-
ing can cause overheating and create a fire hazard. Do not coil
or loop cable around parts of the body.
f. Be sure the proper size ground cable is connected to the
workpiece as close to the work area as possible. Grounds connected to building framework or other remote locations from
the work area increase the possibility of output current passing
through lifting chains, crane cables, or various electrical paths.
g. Keep everything dry, including clothing, work area, cables, elec-
trode holder, and power supply. Fix water leaks immediately.
h. Refer to AWS Standard Z49.1 in Item 6 below for specific ground-
ing recommendations. Do not mistake the work lead for a ground
cable.
4. VENTILATION -- Fumes, particularly in confined spaces, can cause
discomfort and physical harm. Do not breathe fumes. Therefore:
a. At all times provide adequate ventilation in the work area by natu-
ral or mechanical ventilation means. Do not weld, cut, or gouge
on materials such as galvanized zinc, lead, beryllium, or cadmium unless positive mechanical ventilation is provided. Do not
breathe fumes from these materials.
b. Do not operate in locations close to chlorinated hydrocarbon
vapors coming from degreasing or spraying operations. The
heat or arc rays can react with solvent vapors to form phosgene, a highly toxic gas, and other irritant gases.
c. If you develop momentary eye, nose, or throat irritation, while
operating, this is an indication that ventilation is not adequate.
Stop work and take necessary steps to improve ventilation in
the work area. Do not continue to operate if physical discomfort
persists.
d. Refer to AWS Standard Z49.1 in Item 6 below for specific ventila-
tion recommendations.
5. EQUIPMENT MAINTENANCE -- Faulty or improperly maintained
equipment can result in poor work, but most importantly it can cause
physical injury or death through fires or electrical shock. Therefore:
a. Always have qualified personnel perform the installation, trouble-
shooting, and maintenance work. Do not perform any electrical
work unless you are qualified to perform such work.
b. Before performing any maintenance work inside a power sup-
ply, disconnect the power supply from the electrical power
source.
c. Maintain cables, grounding wire, connections, power cord and
power supply in safe working order. Do not operate any equipment in faulty condition.
d. Do not abuse any equipment or accessories. Keep equipment
away from heat sources such as furnaces, wet conditions such
as water puddles, oil or grease, corrosive atmospheres and inclement weather.
e. Keep all safety devices and cabinet covers in position and in
good repair.
f. Use equipment for its intended purpose. Do not modify it in any
manner.
6. ADDITIONAL SAFETY INFORMATION -- For more information on
safe practices for setting up and operating electric welding and
cutting equipment and on good working habits, ask for a free copy
of ESAB's "Precautions and Safe Practices for Electric Welding and
Cutting," Form 52-529. The following publications which are available from the American Welding Society, P.O. Box 351040, Miami,
FL 33135, are recommended to you:
a. "Safety in Welding and Cutting" - AWS Z49.1 (ANSI)
b. "Recommended Safe Practices for Gas-Shielded Arc Welding"
- AWS A6.1
c. "Recommended Safe Practices for the Preparation for Welding
and Cutting of Containers and Piping That Have Held Hazardous Substances" AWS F4.1
d. "Recommended Safe Practices for Plasma Arc Cutting" - AWS
A6.3
e. "Recommended Safe Practices for Plasma Arc Welding: - AWS
C5.1
f. "Recommended Safe Practices for Air Carbon Arc Gouging and
Cutting" - AWS C5.3
2
F-14-260
tection to the rectifier SCR's and diodes. Protection for the
main transformer, bridge rectifier, and inductor is provided by
over-temperature thermal switches located in or on these components. These switches interrupt power in the event of an
overload or overheating condition and automatically reset when
the components have cooled to their normal operating temperature. Dynamic smoothing of the d.c. output current is
provided by an integrally-mounted, fixed inductor.
The solid state circuitry of the PHC-402 produces stable current range and eliminates the "drift" in output of the power
supply as the control components heat up. In addition, this
control circuit has built-in line voltage compensation, which
corrects the output of the power supply for various changes in
the input line voltage. This feature ensures consistency in
cutting conditions even if line voltage changes. The Current
Control potentiometer, on the front panel, sets and regulates
the desired amount of output current for your operation. The
panel-faced dial provides a convenient reference for resetting
previously known conditions. Actual load current and voltage are indicated by an ammeter and voltmeter mounted on the
front panel.
Connections for control functions and auxiliary apparatus are
made from three-plug receptacles. Two three-pin receptacles
are connected in parallel and therefore can be used interchangeably for remote contactor operation or to parallel the
operation of two PHC-402's. The remaining eight-pin receptacle provides connection for auxiliary 115-volts out, remote
current control and remote ammeter indication.
The power supply is designed for ease in moving and handling. Sufficient clearance and reinforcement at its base permits lifting with a fork-lift truck; or raising with a crane or hoist,
using the lifting rings in the top cover.
B. OUTPUT RATING/DUTY CYCLE
II. INSTALLATION
Proper installation can contribute materially to the satisfactory
and trouble-free operation of the power supply. It is suggested that each step in this section be studied carefully and
followed as closely as possible.
A. UNCRATING THE POWER SUPPLY
Immediately upon receipt of the power supply, it should be
inspected for damage which may have occurred in transit.
Notify the carrier of any defects or damage at once.
Carefully remove the power supply from the shipping container. Do not use any lever device which might damage the
unit. Check the container for any loose parts which might
otherwise be lost. Remove all packing materials and make sure
that the passages for cooling air are not obstructed. Check
the contents against the packing list for shortages.
If the unit is not to be installed immediately, store it in a clean,
dry, well ventilated area.
B. LOCATION
The location of the power supply should be carefully selected
to ensure satisfactory and dependable service.
The power supply components are maintained at proper operating temperatures by forced air which is drawn through the
cabinet by the fan unit. For this reason, it is important that the
power supply be located in an indoor-open area where air can
circulate freely at the front, bottom and rear openings of the
cabinet. If space is at a premium, leave at least 2 feet of clearance at the rear of the cabinet. The location should be such
that a minimum of dirt, dust or moisture will be drawn into the
air stream. It is also desirable to locate the unit so that the
cover can be removed easily for cleaning and troubleshooting.
The PHC-402 has two output ratings: the 100% continuous
duty @ 400 amperes means that this rated load (400 amps) can
be applied continuously without a cool-down period; and a
100% duty-1/2 hour @ 500 amperes, which means that this
rated load (500 amps) can be applied continuously for 30 minutes and must then cool down (with fan motors running) for 30
minutes. Cooling periods would be proportionate with shorter
operating periods.
IMPORTANT: Output ratings are designed and based on
an unobstructed supply of clean (no conductive dust) cooling air flow over its internal
components. DO NOT USE FILTERS ON
THIS UNIT. Periodically blow out dirt accumulations, using low pressure air.
C. PRIMARY ELECTRICAL INPUT CONNECTIONS
Precautionary measures should be taken to provide
maximum protection against electrical shock. When
electrical connections are made from the power supply to the main line disconnect switch, be sure that
all power is off by opening the line disconnect switch.
This power supply is a three-phase unit and must be connected to a three-phase power line. Although designed with
line voltage compensation, it is suggested the unit be operated on a separate circuit to assure the performance of the
machine is not impaired due to an overloaded circuit.
1. A line (wall) disconnect switch, with fuses or circuit breakers, should be provided at the main power panel (see Fig.
3
1). The primary power leads should include three power
leads and one ground wire. The wires may be heavy rubber
covered cable, or may be run in a solid or flexible conduit.
Refer to the following table for recommended input conductors and line fuse sizes.
Recommended Sizes for Input Conductors
and Line Fuses
Rated
Output
400
Amp
500
Amp
*Sized per National Electric Code for 75° C rated copper
conductors @ 30° C ambient. Not more than three
conductors in raceway or cable. Local codes should be
followed if they specify sizes other than those listed above.
Rated Input
Voltage/Fre Amps
460V., 60 Hz.
415V., 50 Hz.
380V., 50 Hz
460V., 60 Hz.
415V., 50 Hz.
380V., 50 Hz.
130
144
158
163
180
198
Input
Cond.*
CU/AWG
1
1/0
2/0
2/0
3/0
3/0
Grd
Wire*
CU/AWG
6
3
3
3
3
3
Fuse
Size
Amps
200
225
250
250
300
300
2. For access to primary power input connections on main
contactor and chassis ground connection remove power
supply right side panel.
3. Thread the input conductor cable from the wall disconnect
switch through the 3-1/2-in. dia. access hole in the rear
panel of the power supply. Secure the input cable with a
customer-supplied strain relief or conduit coupling, then
connect the primary power leads to terminals L1, L2, and L3
of the main contactor as shown in Fig. 1. Also connect the
ground wire to the stud provided on the chassis base inside the right-rear of the cabinet.
CAUTION: It is of the utmost importance that the chassis
be connected to an approved electrical
ground to prevent accidental shocking.
4. The primary windings of the main transformer (MTR) and
the primary of the control transformer (CTR) are tapped to
allow reconnection for different primary input voltages. As
shipped from the factory, the power supply is wired for a
460 volt, 60 Hz. input.
To reconnect the unit for a 380 or 415 volt, 50 Hz. input
the following wiring modifications must be made (also refer to schematic and wiring diagrams):
a. Locate the No. 2 AWG insulated cables which connect
the main transformer primary taps MTR-A-H1 to -H4,
MTR-B-H1 to -H4, and MTR-C-H1 to -H4 -- these connections provide the 460 volt, 60 hertz input.
b. Next, locate the H3 and H2 alternate input bus taps on
the face of each primary coil MTR-A, -B, and -C. The
H3 taps provide the connections for a 415 volt, 50 hertz
input, and the H2 taps provide the connections for a
380 volt, 50 hertz input.
c. To change to either the 415 or 380 volt input, you sim-
ply unbolt the 460 volt cable connections on the H4
taps (described in "a" above); and using the same hardware, reconnect the loose end of the cables as follows:
(i) For 415 volt, 50 hertz input, connect:
MTR-A-H1 cable to bus tap MTR-A-H3,
MTR-B-H1 cable to bus tap MTR-B-H3,
MTR-C-H1 cable to bus tap MTR-C-H3.
(ii) Fo r 380 volt, 50 hertz input, connect:
MTR-A-H1 cable to bus tap MTR-A-H2,
MTR-B-H1 cable to bus tap MTR-B-H2,
MTR-C-H1 cable to bus tap MTR-C-H2.
d. To complete the input voltage wiring modifications,
you must also reconnect the control transformer
(CTR). Locate the brown wire (coming from main
contactor) which connects 460 volts from MC-L1 to
the CTR-H9. To change voltages, disconnect this
brown wire from CTR-H9 and reconnect as follows:
MC-L1 to CTR-H6 for 415 volt input, or MC-L1 to CTRH5 for 380 volt input.
5. Recheck all connections to make sure that they are tight,
well insulated, and that the proper connection has been
made.
D. SECONDARY ELECTRICAL OUTPUT CONNECTIONS
Before making any connections to the power supply output
busbars, make sure that the power supply is deenergized. To
be doubly safe, check the output busbars (POS. and NEG.) with
a voltmeter to make sure all power is OFF.
For access to the PHC-402 output voltage busbar/cutting lead
connections and nozzle (pilot arc ground) connection, remove
the left side panel of the power supply.
1. Select the output cables on the basis of one 4/0 AWG, 600
volt insulated copper cable for each 400 amperes of output
current. Do not use ordinary welding cable. Bring these
cables through the large openings provided at the bottom
of the front panel and connect them to the two busbar
terminals mounted in the unit using UL listed pressure wire
connectors (refer to schematic diagram and Figure 1). Each
busbar terminal is labeled with a decal to help facilitate the
basic plasma arc hookup (negative bus to torch electrode
and positive bus to the workpiece).
2. If parallel operation of two units is to be used, consult with
the factory.
3. Make the "Pilot Arc Work" connection between the power
supply bridge assembly and plumbing box using a high
voltage (15,000 v.) Pilot Arc Work Wire (10-ft.) P/N 994065
supplied as part of the PCM-500 Cutting Outfit (also refer
to note in Fig. 1). The Pilot Arc stud connection is adjacent
to the PILOT ARC WORK decal positioned on the left side
4
F-14-260
of the bridge heat sink (see Fig. l). Earlier models contained
a decal identifying this connection as "NOZZLE."
CAUTION: Do not make the "pilot arc work" connec-
tion at any other place. Making the connection elsewhere will cause the pilot arc current to pass through the shunt, and the power
supply will mistake the pilot arc current for
main arc current. The result will be arc current instability during arc starting which can
result in short nozzle and electrode life.
E. CONTROL CONNECTIONS
All control functions are provided from three receptacles located on the power supply's front panel. (Refer to schematic
diagram for proper terminations, and to Figure 1 for location.)
Connections to a remote welding or cutting control assembly
are provided through the 8-pin receptacle (P4), marked "Remote Control." When used, this receptacle supplies 10 amperes of 115-volt a.c. control power for auxiliary apparatus,
remote current control, and connections for remote ammeter
indication.
The two 3-pin receptacles (P3 and P5) marked "Contactor" are
internally connected in parallel and are used for remote
contactor operation. Either of the 3-pin receptacles may be
used to energize the power supply's main contactor from a
remote control station. The remaining receptacle can then be
used to connect to one of the two 3-pin receptacles on a second unit if parallel operation of two units is desired. In this
manner, the main contactor in both units can be actuated from
one remote control source at the same time. An optional 8-foot
interconnecting cable assembly, P/N 993963, with a 3-pin plug
on each end is available for this purpose.
III. OPERATION
CAUTION: Never, under any circumstances, operate the
power supply with cover or side panels removed. In addition to the safety hazard, improper cooling may cause damage to internal components. Also make sure you are
adequately protected before you start cutting -- welders helmet, gloves and ear protection should always be worn.
The current potentiometer indicator dial located on the power
supply front panel primarily serves as a handy reference for
presetting known load conditions that have been derived
through previous operating experience. The accuracy of these
approximated settings can be affected by arc voltage, or the
voltage drop in the secondary output cables. Final current
adjustment of the unit should always be obtained by utilizing
the meters.
A. CUTTING CONTROLS AND SEQUENCE OF OPERATION
The power supply controls and their functions are described
in the operating sequence below:
1. Make the secondary output connections to the positive
and negative output busbar terminals as explained in Section II-D.
Fig. 1 - Interconnection Diagram
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