Miller PSW-1020ATT Owner's manual

Brand: Miller

Model: PSW-1020ATT

Category: Welding System

Type: Owner's manual

January 1991 FORM: OM-744B

Effective With Serial No. KA788188

MODEL: PSW-1020ATT

PSW-2020ATT

SSW-1020ATT

SSW-2020ATT

SSW-1040ATT

SSW-2040ATT

OWNER’S MANUAL

IMPORTANT: Read and understand the entire contents of this manual, with

special emphasis on the safety material throughout the manual, before

installing, operating, or maintaining this equipment. This unit and these

instructions are for use only by persons trained and experienced in the safe

operation of welding equipment. Do not allow untrained persons to install,

operate, or maintain this unit. Contact your distributor if you do not fully

understand these instructions.

MILLER ELECTRIC Mfg. Co.

A Miller Group Ltd., Company

P.O. Box 1079

Appleton, WI 54912 USA

Tel. 414-734-9821

SC 112 847-A PRINTED IN U.S.A

LIMITED WARRANTY − Subject to the terms and conditions

hereof, Miller Electric Mfg. Co., Appleton, Wisconsin warrants to

its Distributor/Dealer that all new and unused Equipment fur-

nished by Miller is free from defect in workmanship and material

as of the time and place of delivery by Miller. No warranty is made

by Miller with respect to engines, trade accessories or other

items manufactured by others. Such engines, trade accessories

and other items are sold subject to the warranties of their respec-

tive manufacturers, if any. All engines are warranted by their

manufacturer for one year from date of original purchase, except

Tecumseh and Onan engines which have a two year warranty.

Except as specified below, Miller’s warranty does not apply to

components having normal useful life of less than one (1) year,

such as spot welder tips, relay and contactor points, MILLER-

MATIC parts that come in contact with the welding wire including

nozzles and nozzle insulators where failure does not result from

defect in workmanship or material.

Miller shall be required to honor warranty claims on warranted

Equipment in the event of failure resulting from a defect within the

following periods from the date of delivery of Equipment to the

original user:

1. Arc welders, power sources, robots, and 1 year. . . . . . . .

components

2. Load banks 1 year. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. Original main power rectifiers 3 years. . . . . . . . . . . . . . . . .

(labor − 1 year only)

4. All welding guns, feeder/guns and torches 90 days. . . . . .

5. All other Millermatic Feeders 1 year. . . . . . . . . . . . . . . . . . .

6. Replacement or repair parts, exclusive of labor 60 days. .

7. Batteries 6 months. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

provided that Miller is notified in writing within thirty (30) days of

the date of such failure.

As a matter of general policy only, Miller may honor claims sub-

mitted by the original user within the foregoing periods.

In the case of Miller’s breach of warranty or any other duty with

respect to the quality of any goods, the exclusive remedies

therefore shall be, at Miller’s option (1) repair or (2) replacement

or, where authorized in writing by Miller in appropriate cases, (3)

the reasonable cost of repair or replacement at an authorized

Miller service station or (4) payment of or credit for the purchase

price (less reasonable depreciation based upon actual use)

upon return of the goods at Customer’s risk and expense.

MILLER’s option of repair or replacement will be F.O.B., Factory

at Appleton, Wisconsin, or F.O.B. at a MILLER authorized serv-

ice facility, therefore, no compensation for transportation costs

of any kind will be allowed. Upon receipt of notice of apparent de-

fect or failure, Miller shall instruct the claimant on the warranty

claim procedures to be followed.

ANY EXPRESS WARRANTY NOT PROVIDED HEREIN

AND ANY IMPLIED WARRANTY, GUARANTY OR REPRE-

SENTATION AS TO PERFORMANCE, AND ANY REMEDY

FOR BREACH OF CONTRACT WHICH, BUT FOR THIS PRO-

VISION, MIGHT ARISE BY IMPLICATION, OPERATION OF

LAW, CUSTOM OF TRADE OR COURSE OF DEALING, IN-

CLUDING ANY IMPLIED WARRANTY OF MERCHAN-

TABILITY OR OF FITNESS FOR PARTICULAR PURPOSE,

WITH RESPECT TO ANY AND ALL EQUIPMENT FUR-

NISHED BY MILLER IS EXCLUDED AND DISCLAIMED BY

MILLER.

EXCEPT AS EXPRESSLY PROVIDED BY MILLER IN WRIT-

ING, MILLER PRODUCTS ARE INTENDED FOR ULTIMATE

PURCHASE BY COMMERCIAL/INDUSTRIAL USERS AND

FOR OPERATION BY PERSONS TRAINED AND EXPERI-

ENCED IN THE USE AND MAINTENANCE OF WELDING

EQUIPMENT AND NOT FOR CONSUMERS OR CONSUMER

USE. MILLER’S WARRANTIES DO NOT EXTEND TO, AND

NO RESELLER IS AUTHORIZED TO EXTEND MILLER’S

WARRANTIES TO, ANY CONSUMER.

LIMITED WARRANTY

EFFECTIVE: MARCH 15, 1989

This warranty supersedes all previous MILLER warranties and is exclusive with no other guarantees or warranties expressed or implied.

OM-744B − 1/91

Before unpacking equipment, check carton for any

damage that may have occurred during shipment. File

any claims for loss or damage with the delivering car-

rier. Assistance for filing or settling claims may be ob-

tained from the distributor and/or the equipment manu-

facturer’s Transportation Department.

When requesting information about this equipment, al-

ways provide the Model Description and Serial or Style

Number.

Use the following spaces to record the Model Designa-

tion and Serial or Style Number of your unit. The infor-

mation is located on the data card or the nameplate.

Model

Serial or Style No.

Date of Purchase

RECEIVING-HANDLING

TABLE OF CONTENTS

Section No. Page No.

SECTION 1 − SAFETY RULES FOR OPERATION OF PORTABLE RESISTANCE

SPOT WELDING EQUIPMENT

1-1. Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-2. Installation 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3. Safety Devices 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4. Personal Safety 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-5. Burn Prevention 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-6. Fumes 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-7. Fire Prevention 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-8. Protection Of Others 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-9. Cords 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-10. Hoses 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-11. Maintenance 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-12. Standard Index 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2 − SAFETY PRECAUTIONS AND SIGNAL WORDS

2-1. General Information And Safety 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-2. Safety Alert Symbol And Signal Words 2. . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 3 − SPECIFICATIONS

3-1. Duty Cycle 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-2. Description 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 4 − INSTALLATION OR RELOCATION

4-1. Location 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-2. Tong Installation 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-3. Coolant Connections 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-4. Air Connections 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-5. Tong Pressure Adjustment 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-6. Remote Foot Switch Receptacle And Installation

(Stationary Models Only) 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-7. Hanging Bracket Installation (Portable Models Only) 7. . . . . . . . . . . . .

4-8. Electrical Input Connections 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section No. Page No.

SECTION 5 − OPERATOR CONTROLS

5-1. Power Switch 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-2. Pilot Light 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-3. Weld Current Control 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-4. Weld Time Control 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-5. Squeeze Time Control 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-6. Weld Switch 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-7. Start Switch 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-8. Speed Control Valve 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 6 − SEQUENCE OF OPERATION

6-1. Spot Welding 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-2. Shutting Down 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 7 − MAINTENANCE & TROUBLESHOOTING

7-1. Routine Maintenance 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-2. Dressing Tong Tips 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-3. Replacing Tong Tips 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-4. Changing Tongs 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-5. Control Circuit Protection 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-6. Troubleshooting 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 8 − ELECTRICAL DIAGRAMS

Diagram 8-1. Circuit Diagram For Portable 10 KVA Models

And Portable 20 KVA Models 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 8-2. Circuit Diagram For Stationary 10 KVA Models

And Stationary 20 KVA Models 15. . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 8-3. Wiring Diagram For SSW-1020ATT And

SSW-1040ATT Model Spot Welders 16. . . . . . . . . . . . . . . . . . . . . .

Diagram 8-4. Wiring Diagram For SSW-2020ATT And

SSW-2040ATT Model Spot Welders 16. . . . . . . . . . . . . . . . . . . . . .

Diagram 8-5. Wiring Diagram For Model PSW-2020ATT Spot Welder 17. . . . .

Diagram 8-6. Wiring Diagram For Model PSW-1020ATT Spot Welder 17. . . . .

SECTION 9 − PARTS LIST

Figure 9-1. Main Assembly 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-2. Resistance Spot Welder, Air 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-3. RFS-10/20 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-4. Pedestal, Air Operated 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-5. Control Box 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-6. Tongs 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9-7. Valve-Air w/Components 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LIST OF CHARTS AND TABLES

Table 3-1. Specifications 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4-1. Input Conductor And Fuse Size 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7-1. Maintenance Schedule 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7-2. Troubleshooting 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

OM-744 Page 3

SECTION 3 − SPECIFICATIONS

Table 3-1. Specifications

Model

Work Capacity

Combined Thickness

Mild Steel

Rated Output

50% Duty Cycle

Weight

Net Ship

Portable

10 KVA

Portable

20 KVA

Stationary

10 KVA

Stationary

20 KVA

150 lbs.

(68 kg)

165 lbs.

(75 kg)

182 lbs.

(83 kg)

195 lbs.

(89 kg)

222 lbs.

(101 kg)

246 lbs.

(112 kg)

199 lbs.

(90 kg)

217 lbs.

(98 kg)

3/16 in. (4.7 mm)

1/4 in. (6.3 mm)

3/16 in. (4.7 mm)

1/4 in. (6.3 mm)

10 KVA

20 KVA

10 KVA

20 KVA

Spot

Welder

Ratings

Tongs-Length

Output Amps ±10%

Input Amps At 220

Volts

10 KVA Models 20 KVA Models

6 in.

(152 mm)

9500

100

12 in.

(304 mm)

7500

18 in.

(457 mm)

6500

6 in.

(152 mm)

12500

200

12 in.

(304 mm)

10500

170

18 in.

(457 mm)

9000

142

*Dimension depends upon length of tongs.

SC-112 847-A

1/2 in.

(12.7 mm)

Dia. 4 Holes

Inches

37-1/8

26 + Tong Length

10-7/8

9-1/2

11/16

Millimeters

1244.6

943

660.4 + Tong Length

152.4

304.8

457.2

276.2

241.3

17.5

19-1/2

20-7/8

11/16

495.3

530.2

17.5

Figure 3-1. Overall Dimensions And Base Mounting Hole Layout For Stationary Models

OM-744 Page 4

SB-112 8451-A

Inches

14-3/8

12-1/4

1-1/2

15-1/8

Millimeters

365.1

406.4

311.2

38.1

384.2

Figure 3-2. Overall Dimensions For Portable Models

3-1. DUTY CYCLE

The duty cycle of a resistance spot welder is the per-

centage of a one minute period that a resistance spot

welder can be operated without causing overheating or

damage to the unit. These resistance spot welders are

rated at 50% duty cycle, which means that they can be

operated for thirty seconds out of every minute.

EXCEEDING DUTY CYCLE RATINGS will

damage the resistance spot welder

• Do not exceed 50% duty cycle.

3-2. DESCRIPTION

These models of resistance spot welders are air oper-

ated, and require a supply capable of providing 60 to 100

psi (414 to 689 K Pa) of air pressure.The welders are

water cooled, and require a supply capable of providing

4 psi (28 KPa) of water pressure.These models are

available as portable or stationary units. The portable

models operate on 50 or 60 Hertz, 220 volts ac, single-

phase power. The stationary models operate on 50 or 60

Hertz, 220 or 440 volts ac, single-phase power. In addi-

tion to a ten-step WELD CURRENT Control and a

WELD TIME Control, all models have a SQUEEZE

TIME Control, which allows the tongs sufficient time to

close before energizing the weld control, and a Speed

Control Valve, which controls the rate at which the tongs

close.

IMPORTANT: For a complete listing of Accessories

and Optional Equipment, see back cover of this Owner’s

Manual.

SECTION 4 − INSTALLATION OR RELOCATION

4-1. LOCATION

WARNING: FALLING EQUIPMENT can

cause serious personal injury and equip-

ment damage.

• Use equipment of adequate capacity to lift the

unit.

• Place unit on a proper skid.

• Secure unit during transport so it cannot tip or

fall.

• If using lift forks to handle this unit, be sure the

lift forks are long enough to extend out of the

opposite side of the base.

Using lift forks too short will expose internal

components to damage should the tips of the lift

forks penetrate the bottom of the unit.

When installing the unit, allow at least 6 in. (152 mm) of

clearance space at the rear of the unit for making neces-

sary connections. Consider the input power require-

ments as well as coolant (water) needs when choosing a

location.

The location should allow room to remove the side panel

for installation, maintenance, and repair procedures.

The service life and efficiency of this unit are reduced

when the unit is subjected to high levels of dust, dirt,

moisture, corrosive vapors, and extreme heat.

IMPORTANT: All directions, such as left or right, are

with respect to the operator facing the unit front panel.

Retain all hardware removed during this procedure for

reinstallation unless specifically told otherwise.

OM-744 Page 5

4-2. TONG INSTALLATION (Figure 4-1)

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting or installing.

• Allow tongs and tong tips to cool before touch-

ing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

SA-135 051-A

COOLANT IN Hose

To COOLANT IN Tube

COOLANT IN Hose

From Water Supply

(Customer Supplied)

Water Pressure

Switch

COOLANT OUT

Tube

COOLANT IN

Tube

Top Tong

Securing

Screws

Spatter

Guard

Top Tong Output

Hose To Bottom

Tong Input Hose

Bottom Tong

Input Hose

Tong

Tips

Coolant

Hose

Fitting

Hose

Clamp

Bottom Tong

Output Hose

Top Tong

Input Hose

Setscrew

Cam Nut

Figure 4-1. Tong Installation And Coolant Connections

IMPORTANT: Be sure ends of tongs are clean and free

of corrosion before installing.

A. Bottom Tong Installation

WARNING: INCORRECT PARTS can cause

electric shock hazard and transformer dam-

age.

• Do not replace polyester glass insulating strip

with a metal strip.

• Always use only correct replacement parts

according to parts list at the end of this manu-

al.

1. Loosen socket head setscrew located below the

spatter guard on the front of the transformer

housing (see Figure 4-1).

2. Rotate cam nut on left side of housing counter-

clockwise to release pressure from bottom tong

holder.

3. Insert tong into bottom tong holder as far as pos-

sible, positioning tong so that tip is pointing

straight up.

IMPORTANT: Before proceeding to Step 4, make sure

that the polyester glass insulating strip is not cracked or

broken, and that it is properly positioned above the bot-

tom tong.

4. Turn cam nut clockwise to secure tong in bottom

tong holder.

5. Tighten socket head setscrew, locking the cam in

place.

B. Top Tong Installation

1. Loosen the four top tong securing screws located

on top of transformer housing (see Figure 4-1).

2. Insert top tong into top tong holder, positioning

tong so that the tip mates against bottom tong tip

when tongs are closed.

3. Tighten securing screws, locking tong in place.

OM-744 Page 6

4-3. COOLANT CONNECTIONS (Figure 4-1)

IMPORTANT: This unit is equipped with a Water Con-

trol Pressure Switch to insure proper cooling. If the wa-

ter supply has not been turned on, or does not have suf-

ficient pressure to activate the switch, no weld output

will be available at the tongs.

1. Connect tong coolant hoses to barbed fittings on

tongs as shown in Figure 4-1,and secure with

hose clamps.

2. Obtain two coolant hoses of desired length with

an inside diameter of 5/16 in. (7.9 mm) for con-

nections to COOLANT IN supply and coolant re-

turn or waste drain.

3. Connect end of one customer supplied hose to

COOLANT IN fitting. Secure hose using supplied

hose clamps (see Figure 4-1). Connect remain-

ing end of this customer supplied hose to water

supply.

4. Connect one end of remaining customer supplied

hose to COOLANT OUT tube extending from

rear of unit, and connect other end to coolant re-

turn or waste drain. Secure hose using supplied

hose clamps (see Figure 4-1).

SC-112 848-A

Portable Models

Air In Hose

Stationary Models

Air In Hose

Lubricator

Pressure Gauge

Pressure Adjustment Control

Pressure Regulator

Regulator Plug

To Air Supply

Air Filter

Figure 4-2. Air Connections

4-4. AIR CONNECTIONS (Figure 4-2)

The air supply used to operate these units must be ca-

pable of providing 60 to 100 psi (414 to 689 kPa) of air

pressure. Install a valve at the air supply that can turn

the air supply on and off.

To keep the air lines and associated components in the

resistance spot welder clean, trouble free, and function-

ing properly, an air filter, pressure regulator, pressure

gauge, and lubricator are provided. These components

are shipped assembled with the exception of the pres-

sure gauge. Install the pressure gauge in one of the

holes on either side of the pressure regulator (see Fig-

ure 4-2). Install one of the supplied plugs into the unused

hole.

IMPORTANT: See manufacturer’s instructions

supplied with air filter assembly for complete installation

and preparation instructions.

1. Obtain two hoses of desired length with an inside

diameter of 5/16 in. (7.9 mm) for making required

air connections.

2. Connect one hose from air supply to input con-

nector on air filter.

3. Connect remaining hose from lubricator output

connector to AIR IN connector on control box of

resistance spot welder.

4. Set pressure regulator so that air pressure at re-

sistance spot welder is in the 60 to 100 psi (414 to

689 kPa) range.

OM-744 Page 7

4-5. TONG PRESSURE ADJUSTMENT (Figure

4-3)

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting or installing.

• Allow tongs and tong tips to cool before touch-

ing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

CAUTION: EXCESSIVE TONG PRESSURE

can damage tong tips.

• Do not use the tongs as a clamp or vice to hold

workpiece together.

If the two pieces of material to be welded do not

make good contact at the point of the intended

weld, clamp material to provide good contact

between surfaces.

IMPORTANT: Correct tong pressure is necessary to

create a quality weld and to prevent damage to tong tips.

Excessive tong pressure causes the weld nugget area

to dimple, material to splash out around the nugget area,

and molten material to eject from the weld area.

If tong pressure is too weak, parts are loose when the

tongs are closed, severe arcing occurs between all ma-

terial interfaces, and no weld can be made.

Ref. SB-112 849-A

Figure 4-3. Tong Pressure Adjustment

IMPORTANT: Tong pressure is adjustable, and must be

checked and/or set before operation.

To adjust tong pressure, proceed as follows:

A. Increasing Tong Pressure

1. Rotate nut A counterclockwise.

2. Rotate nut B counterclockwise until it is tight.

3. Check tong pressure.

B. Decreasing Tong Pressure

1. Rotate nut A clockwise.

2. Rotate nut B clockwise until it is tight.

3. Check tong pressure.

4-6. REMOTE FOOT SWITCH RECEPTACLE AND

INSTALLATION (Stationary Models Only)

(Figure 4-4)

The FOOT CONTROL Receptacle provides a connec-

tion point for the Remote Foot Switch. See Section 5

−

for operation of Remote Foot Switch. To make connec-

tion, insert plug from foot control into FOOT CONTROL

receptacle on front of the control box, and rotate plug ful-

ly clockwise.

Ref. SC-112 663-A

Remote Foot

Switch

Remote Foot

Switch

Cord And Plug

Figure 4-4. Remote Foot Switch Installation

4-7. HANGING BRACKET INSTALLATION (Porta-

ble Models Only) (Figure 4-5)

WARNING: ELECTRIC SHOCK can kill; HOT

SURFACES can burn skin.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting, maintaining, or servicing.

Lockout/tagging procedures consist of padlock-

ing line disconnect switch in open position, re-

moving fuses from fuse box, or shutting off and

red-tagging circuit breaker or other disconnect-

ing device.

MOVING PARTS can cause serious injury.

• Keep away from pinch points.

HOT SURFACES can cause severe burns.

• Allow cooling period before servicing.

1. Remove hardware from front of resistance spot

welder handles.

2. Install and secure bracket to transformer housing

using hardware removed in Step 1. (Discard

supplied mounting hardware.)

3. Install and secure eye bolt to top of hanging

bracket using supplied hardware.

OM-744 Page 8

SC-113 041-A

Eye Bolt

Hanging Bracket

Split Washer

Lock Nut

Split Washer

Bolt

Spacer

Figure 4-5. Hanging Bracket Installation

4-8. ELECTRICAL INPUT CONNECTIONS (Fig-

ure 4-6)

A. Electrical Input Requirements

These resistance spot welders are designed to operate

from a single-phase, 50 or 60 Hertz, ac power supply

which has a line voltage rating that matches the voltage

shown on the nameplate. Consult the local electric utility

if there is any question about the type of electrical sys-

tem available at the installation site or how proper con-

nections to the resistance spot welder are to be made.

B. Input Conductor Connections

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Install a fusible line disconnect switch in the

input circuit to the resistance spot welder.

This provides a safe and convenient means to

completely remove all electrical power from the

resistance spot welder whenever it is necessary

to inspect or service the unit.

• Shut down unit and disconnect input power

employing ”lockout/tagging procedures” be-

fore inspecting or installing.

Lockout/tagging procedures consist of padlock-

ing line disconnect switch in open position, re-

moving fuses from fuse box, or shutting off and

red-tagging circuit breaker or other disconnect-

ing device.

• Connect input conductors to the resistance

spot welder before connecting to single-

phase input power.

Table 4-1 provides guidelines for selecting the

proper size input conductors and line fuses. The

input conductors should be covered with an in-

sulating material that complies with national,

state, and local electrical codes.

• Ground in accordance with the National Elec-

trical Code, state, and local codes.

Proper installation can contribute to the satisfactory and

trouble-free operation of the resistance spot welder.

Follow the instructions in this section carefully.

1. Install terminal lugs of adequate amperage ca-

pacity and correct stud size onto input and

ground conductors.

2. Remove left side panel from resistance spot

welder.

3. Loosen strain relief clamp located on rear panel

of unit.

4. Insert and route the two input conductors and the

ground conductor through the strain relief, up to

the power switch on the front panel.

WARNING: ELECTRIC SHOCK can kill.

• Do not connect an input conductor to the

ground conductor in the unit.

• Do not connect the ground conductor to an

input line conductor.

Incorrect input connections can result in an elec-

trically energized chassis of the resistance spot

welder. The ground terminal is connected to the

chassis of the resistance spot welder and is for

grounding purposes only.

S-0092/9-90

OM-744 Page 9

5. Connect the two input conductors to the line ter-

minals on the power switch, and connect the

ground conductor to the ground terminal (see

Figure 4-6). Secure connections using supplied

hardware.

6. Tighten strain relief clamp.

7. Reinstall and secure left side panel.

8. Connect remaining end of ground conductor to a

proper ground. Use a grounding method that is

acceptable to the local electrical inspection au-

thority.

Table 4-1. Input Conductor And Fuse Size*

Model

Input

Voltage

Input

Conductor

Size

(AWG)

Ground

Conductor

Size

(AWG)

Fuse

Size In

Amperes

10KVA 220 6 10 80

440 10 10 40

20KVA 220 3 8 150

440 6 10 70

*Conductor size is based on the 1990 Edition of the National

Electrical Code (NEC) specifications for allowable ampacities

of insulated copper conductors, having a temperature rating of

167

°F (75°C), with not more than three single current-carrying

conductors in a raceway (Article 310 of NEC). (The ground

conductor is not counted as a current-carrying conductor.)

*Fuse size is based on not more than 200 percent of the rated

input amperage of the welding power source (Article 630 of

NEC).

SC-113 033-B

Ground Conductor

Line

Disconnect

Switch

20 KVA Models

10 KVA Models

Line

Power

Ground

Switch

Terminal

Line Terminals

Terminals

Power

Switch

Ground

Terminal

Figure 4-6. Input Conductor Connections (Stationary Model Illustrated)

SECTION 5 − OPERATOR CONTROLS

5-1. POWER SWITCH (Figures 5-1 And 5-2)

The POWER switch provides on and off control of the

input electrical power. Placing the POWER switch in the

ON position energizes the unit and places it in a ready-

OM-744 Page 10

to-operate status. Placing the switch in the OFF position

shuts the unit down.

5-2. PILOT LIGHT (Figures 5-1 And 5-2)

The pilot light indicates when the unit is energized and in

a ready-to-weld status. The pilot light is on whenever the

POWER switch is in the ON position.

5-3. WELD CURRENT CONTROL (Figures 5-1

And 5-2)

This control provides a means of selecting weld current.

The scale surrounding the WELD CURRENT Control is

a relative scale only, it does not indicate a specific am-

perage value. Rotating the control clockwise increases

weld current. Position 1 represents minimum current,

and position 10 represents maximum current. Changing

the weld current value does not affect the duty cycle rat-

ing.

5-4. WELD TIME CONTROL (Figures 5-1 And 5-2)

This control provides a means of selecting the duration

of the spot weld. The weld time period may be adjusted

from 0 (zero) to 9.99 seconds by rotating the control’s

three adjustment knobs. Rotating each knob clockwise

increases the weld time.

Weld time begins to elapse when the time set on the

SQUEEZE TIME Control has expired (see Section 5-5).

CAUTION: ARCING can damage WELD

CURRENT CONTROL contacts.

• Do not rotate the WELD CURRENT CON-

TROL while welding.

5-5. SQUEEZE TIME CONTROL (Figures 5-1 And

5-2)

This control is provided to allow the tongs sufficient time

to close and make contact with the work before weld

current is available. The length of squeeze time may be

adjusted from 0 (zero) to 9.99 seconds by rotating the

control’s three adjustment knobs. Rotating each knob

clockwise increases the squeeze time. Squeeze time

starts to elapse when the Remote Foot Switch or Start

Switch is depressed (see Section 5-8).

CAUTION: ARCING can damage tong tips.

• Be sure tongs close before time set on

SQUEEZE TIME control has elapsed.

5-6. WELD SWITCH (Figures 5-1 And 5-2)

The WELD SWITCH allows the operator to check tong

pressure and alignment without weld current present at

the tongs. When the WELD SWITCH is OFF, depress-

ing the Remote Foot Switch or Start Switch (see Section

5-8) will close the tongs without starting current. When

the WELD SWITCH is ON, the tongs will have weld cur-

rent present after the squeeze time expires.

SC-112 847-A

Fuse F2

Pilot

Light

Power

Switch

Foot

Control

Receptacle

Weld Time

Control

Weld Switch

Fuse F1

Squeeze Time

Control

Weld Current

Control

Figure 5-1. Operator Controls For Stationary

Models

SB-112 845-A

Pilot

Light

Fuse F1

Power

Switch

Weld Time

Control

Weld Current

Control

Squeeze Time

Control

Weld

Switch

Fuse F2

Figure 5-2. Operator Controls For Portable Mod-

els

5-7. START SWITCH (Figure 5-3)

On portable models, the Start Switch is located on the

left handle of the unit. On stationary models, the Remote

Foot Switch functions as the Start Switch. When the

Start Switch is depressed, the tongs close, and squeeze

time begins. If the Start Switch or Remote Foot Switch is

released while the SQUEEZE TIME Control is operating

(see Section 5-5), the tongs open, and the unit resets for

another weld cycle. However, if the Start Switch or Re-

mote Foot Switch is depressed until the squeeze time

has elapsed and weld time has begun, the Starat Switch

or Remote Foot Switch may be released and the tongs

will stay closed until the weld time set on the WELD

OM-744 Page 11

TIME Control has elapsed. If the workpiece is to be left

between the tongs after the weld time has elapsed, the

operator must keep the Start Switch or Remote Foot

Switch closed for the entire weld sequence and whatev-

er holding time is desired after weld time has elapsed.

5-8. SPEED CONTROL VALVE (Figure 5-3)

The Speed Control Valve is used to control the speed at

which the tongs close. Rotating the speed adjustment

handle clockwise decreases air flow, thus reducing the

speed at which tongs close. Rotating the handle coun-

terclockwise increases air flow, thus increasing speed at

which tongs close. Adjust the valve to close the tongs as

quickly as required for the spot welding application.

To adjust the Speed Control Valve, loosen lock nut lo-

cated below speed adjustment handle, rotate speed ad-

justment handle to required position, and tighten lock

nut.

SB-112 846-

Lock Nut

Speed Adjustment Handle

Speed Control Valve

*Start Switch

*Portable Models Only

Figure 5-3. Start Switch And Speed Control Valve

OM-744 Page 12

SECTION 6 − SEQUENCE OF OPERATION

6-1. SPOT WELDING

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Keep all covers and panels in place while

operating.

Warranty is void if the wire feeder is operated

with any portion of the outer enclosure removed.

SPARKS AND HOT SURFACES can burn

eyes and skin and start fires.

• Wear correct eye, ear, and body protection.

• Watch for fire.

• Keep a fire extinguisher nearby, and know

how to use it.

• Do not use near flammable material.

• Allow work and equipment to cool before han-

dling.

FUMES AND GASES can seriously harm

your health.

• Keep your head out of the fumes.

• Ventilate to keep from breathing fumes and

gases.

• If ventilation is inadequate, use approved

breathing device.

MOVING PARTS can cause serious injury.

• Keep clear of pinch points.

MAGNETIC FIELDS FROM HIGH CUR-

RENTS can affect pacemaker operation.

• Wearers should consult their doctor before

going near arc welding, gouging, or spot

welding operations.

See Section 1 - Safety Rules For Operation Of

Portable Resistance Spot Welding Equipment.

1. Install and connect unit according to Section 4.

2. Set SQUEEZE TIME Control for required pre-

weld time (see Section 5-5).

3. Set WELD TIME Control for required weld time

(see Section 5-4).

4. Rotate WELD CURRENT Control to required set-

ting (see Section 5-3).

5. Turn on air supply.

6. Place WELD SWITCH in ON position (see Sec-

tion 4-6).

7. Start coolant flow.

8. Place POWER Switch in ON position.

9. Position workpieces to be welded between the

tongs.

CAUTION: EXCESSIVE TONG PRESSURE

can damage tong tips.

• Do not use the tongs as a clamp or vice to hold

workpiece together.

If two pieces of material do not make good con-

tact at the point of the intended weld, some type

of clamping device must be employed.

10. Depress Start Switch or Remote Foot Switch to

initiate weld sequence.

11. When weld time has expired, release Start

Switch or Remote Foot Switch. The resistance

spot welder will be ready for another weld cycle.

CAUTION: EXCEEDING DUTY CYCLE

RATINGS will damage resistance spot weld-

er.

• Do not exceed indicated duty cycles.

6-2. SHUTTING DOWN

1. Place POWER Switch in OFF position.

2. Turn off coolant supply.

3. Turn off air supply.

SECTION 7 − MAINTENANCE & TROUBLESHOOTING

7-1. ROUTINE MAINTENANCE (Table 7-1)

IMPORTANT: Every six months inspect the labels on

this unit for legibility. All precautionary labels must be

maintained in a clearly readable state and replaced

when necessary. See Parts List for part number of

precautionary labels.

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting, maintaining, or servicing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

MOVING PARTS can cause serious injury.

• Keep away from pinch points.

HOT SURFACES can cause severe burns.

• Allow cooling period before servicing.

Maintenance to be performed only by qualified

persons.

OM-744 Page 13

Table 7-1. Maintenance Schedule

Frequency* Maintenance

Every month. Units in heavy service environ-

ments:

Check labels and input cable.

Every 3 months. Check input cable (see Section

7-1A).

Lubricate tong assembly (see

Section 7-1D).

Every 6 months. Check all labels (see IMPORT-

ANT block, Section 7-1).

Clean internal parts (see Section

7-1B).

Inspect tongs and tips (see Sec-

tions 7-1C and 7-2).

*Frequency of service is based on units operated

40 hours per week. Increase frequency of maint-

enance if usage exceeds 40 hours per week.

A. Input Cables

WARNING: Read and follow safety informa-

tion at beginning of entire Section 7-1 be-

fore proceeding.

Every three months inspect cables for breaks in insula-

tion. Repair or replace cables if insulation breaks are

present. Clean and tighten connections at each inspec-

tion.

B. Internal Cleaning

WARNING: Read and follow safety informa-

tion at beginning of entire Section 7-1 be-

fore proceeding.

Every six months blow out or vacuum dust and dirt from

the inside of the unit. Remove the side panel, and use a

clean, dry airstream or vacuum suction for the cleaning

operation. If dusty or dirty conditions are present, clean

the unit monthly.

C. Tong Inspection

WARNING: Read and follow safety informa-

tion at beginning of entire Section 7-1 be-

fore proceeding.

Every six months or as often as is required to maintain

equipment in good working condition, inspect tong tips

for dents, nicks, or mushrooming, and inspect tong ends

for bends or nicks.

D. Lubricating Tong Assembly (Figure 7-1)

WARNING: Read and follow safety informa-

tion at beginning of entire Section 7-1 be-

fore proceeding.

Lubricate the tong assembly every three months (every

month if usage is heavy) using silicone or synthetic lubri-

cants. An oil hole is provided on the top side of the trans-

former housing. Do not over oil.

Ref. SB-112 849-A

Oil Hole

Figure 7-1. Lubricating Tong Assembly

7-2. Dressing Tong Tips

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting, maintaining, or servicing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

HOT SURFACES can cause severe burns.

• Allow tongs and tong tips to cool before serv-

icing.

• Keep away from pinch points.

Obtain Tip Dresser from Distributor to dress tong tips,

and use it according to its instructions. For a complete

listing of Accessories and Optional Equipment, see

back cover of this Resistance Spot Welder Owners

Manual.

Tong tips are most effectively dressed by machining the

tips. One of the most common mistakes in tip dressing is

the hand filing of the face of the tip which usually results

in a dome-shaped surface where a flat surface is re-

quired. Only in the hands of a very experienced person

can tips be properly dressed, and filed tip faces usually

are not parallel. Therefore, hand filing is discouraged.

The tendency for the file to be used at an angle is always

present, resulting in gross tip mismatching and poor

quality welds.

A file, however, can be advantageously used in remov-

ing the ”mushroom” from the tips providing the filing is

confined to the tapered sides of the tip instead of on the

surface of the tip.

One of the hand operated tip dressers uses emery cloth,

crocus cloth or sandpaper. These abrasives are placed

over a hardened tip contour die in a special holder and a

very light pressure is exerted on the tips. The rapid twist-

OM-744 Page 14

ing motion of the dresser in sanding the tips results in a

perfectly dressed tip face.

7-3. REPLACING TONG TIPS

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting or installing.

• Allow tongs and tong tips to cool before touch-

ing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

EXCESSIVE FORCE can damage tips or

tongs.

• Be careful not to deform tips or tongs during

replacement.

To replace tong tip, remove present tip using a welding

tip extractor or similar device, and press new tip into end

of tong.

7-4. CHANGING TONGS

When changing resistance spot welder tongs, or if tongs

become worn, replace tongs according to Section 4-2.

7-5. CONTROL CIRCUIT PROTECTION

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting, maintaining, or servicing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

INCORRECT FUSE can damage unit.

• Use only replacement fuse of same size,

type, and rating (see Parts List).

Fuses F1 And F2

For control circuit protection, these resistance spot

welders are equipped with two fuses, F1 and F2, located

on the front control panel (see Figure 5-1 and 5-2).

If F1 and/or F2 should open, the unit would be complete-

ly inoperative. If F1 and/or F2 open repeatedly, contact

the nearest Factory Authorized Service Station. To re-

place either fuse, proceed as follows:

1. Place the POWER switch in the OFF position.

2. Depress and rotate fuse holder cover counter-

clockwise.

3. Pull out fuse with cover when fuse holder cover is

free.

4. Insert new fuse into fuse holder cover.

5. Install fuse with fuse holder cover back into unit.

6. Depress and rotate fuse holder cover clockwise

until cover is secure.

7. Resume operation.

7-6. TROUBLESHOOTING

WARNING: ELECTRIC SHOCK can kill.

• Do not touch live electrical parts.

• Shut down unit and disconnect input power

employing lockout/tagging procedures be-

fore inspecting, maintaining, or servicing.

Lockout/tagging procedures consist of pad-

locking line disconnect switch in open position,

removing fuses from fuse box, or shutting off

and red-tagging circuit breaker or other discon-

necting device.

MOVING PARTS can cause serious injury.

• Keep away from pinch points.

HOT SURFACES can cause severe burns.

• Allow cooling period before servicing.

Troubleshooting to be performed only by

qualified persons.

It is assumed that the unit was properly installed accord-

ing to Section 4 of this manual, the operator is familiar

with the function of controls, the resistance spot welder

was working properly, and that the trouble is not related

to the welding process.

The following table is designed to diagnose and provide

remedies for some of the troubles that may develop in

this resistance spot welder. Use this table in conjunction

with the circuit diagram while performing troubleshoot-

ing procedures. If the trouble is not remedied after per-

forming these procedures, contact the nearest Factory

Authorized Service Station. In all cases of equipment

malfunction, strictly follow the manufacturer’s proce-

dures and instructions.

OM-744 Page 15

Table 7-2. Troubleshooting

TROUBLE CAUSE REMEDY

No weld current. Open line fuse. Check and replace line fuse, if necessary.

Fuse F1 and/or fuse F2 open. Check and replace F1 and/or F2, if necessary

(see Section 7-5).

Contactor W. Check W points for wear, and replace points if

necessary.

POWER switch S1. Replace S1.

Start switch PB1 or Remote

Foot Switch S4.

Replace PB1 or S4.

No water, or insufficient water

pressure.

Check to see if valve from water supply is open

and has sufficient pressure (see Section 4-4).

Longer than normal WELD

TIME required.

Condition of tong tips. Replace or resurface tong tips (see Sections 7-2

and 7-3).

Low line voltage. Check for loads on same circuit and remove.

Material being welded is dirty or

has excessive oxide coating.

Clean material.

Incorrect tong pressure. Adjust tong pressure (see Section 4-5).

Burn through at point of weld. Weld time too long. Readjust weld time (see Section 5-4). Check

timer TD1 and replace if necessary.

Incorrect tong pressure. Adjust tong pressure (see Section 4-5).

Squeeze time too short. Increase squeeze time (see Section 5-5). Check

timer TD2, and replace if necessary.

Shape of tips. Replace or dress tong tips (see Sections 7-2 and

7-3).

Tong tips not aligned. Realign tong tips (see Section 4-2).

Tongs close too slowly. Low air pressure. Correct air pressure at source or at regulator

(see Section 4-4).

Air valve AS1 not opening all

the way.

Replace AS1 if necessary.

Speed Control Valve. Adjust or replace Speed Control Valve (see Sec-

tion 5-8).

OM-744 Page 16

SECTION 8 − ELECTRICAL DIAGRAMS

Circuit Diagram No. SA-128 142

Diagram 8-1. Circuit Diagram For Portable 10 KVA Models And Portable 20 KVA Models

Circuit Diagram No. SA-128 145

Diagram 8-2. Circuit Diagram For Stationary 10 KVA Models And Stationary 20 KVA Models

OM-744 Page 17

Wiring Diagram No. SB-128 125

Diagram 8-3. Wiring Diagram For SSW-1020ATT And SSW-1040ATT Model Spot Welders

Wiring Diagram No. SB-128 126

Diagram 8-4. Wiring Diagram For SSW-2020ATT And SSW-2040ATT Model Spot Welders

OM-744 Page 18

Wiring Diagram No. SB-128 128

Diagram 8-5. Wiring Diagram For Model PSW-2020ATT Spot Welder

Wiring Diagram No. SB-128 129

Diagram 8-6. Wiring Diagram For Model PSW-1020ATT Spot Welder

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Miller PSW-1020ATT Owner's manual

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Model: PSW-1020ATT

Category: Welding System

Type: Owner's manual

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Miller PSW-1020ATT Owner's manual

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