Introduction to words and terms

AC. Alternating current. This is the type of electrical supply normally standard in South Africa on resistance welders.

AC SWITCH. One of the names used for the switch that allows electricity into the transformer and is controlled by the welding timer. See also thyristor, S.C.R 

AMP. The electrical component of the electrical supply that does the work of melting the steel during a weld.

ANALOG. Normally associated with older type timers that have adjustment by dials or knobs on the face of the timer.

COPPER CHROME ZIRCONIUM. Resistance or Spot welding copper which is an alloy of copper, chrome and zirconium. General purpose copper for welding tips and electrodes

COPPER CHROME. Resistance or Spot welding copper which is an alloy of copper and chrome. General purpose copper used for the manufacture of tips and electrodes

COPPER BERYLLIUM. Resistance or Spot welding copper which is an alloy of copper and beryllium. Really hard copper alloy used in hard work electrode such as projection welders 

COPPER TUNGSTEN.  Resistance or Spot welding copper which is an alloy of copper and tungsten. Extremely hard copper used as inserts on projection welding tooling.

COOL. The time that is allowed for the weld to cool or the drying time of the molten steel in the weld area.

CONSTANT CURRENT. The ability of the timer system to hold the welding heat or current within a preset upper and lower limit.

CONSTANT AIR. The ability of the timer system to hold the air pressure within a preset upper and lower limit.

CURRENT. Normally refers to the welding amps or welding current used to achieve a weld during the welding process.

CYLINDER. The air cylinder is the standard method used on air operated spot welders to close the welding times.

CYCLES. The standard method of measuring time with a welding timer. Its is based on the fact that in South Africa we are supplied electrical power at 50hz per second therefore a weld period of 50cycles is equivalent to one second.

DC. There was a time when resistance welders went through a period using DC or direct current. This seems to have been replaced with machines that weld using high frequency welding.

DIGITAL. Most modern timer controls have settings that are digitally based and have a keypad on the front and settings are punched in on this keypad.

DOWN SLOPE. While the welding cycle is taking place the weld is slowly reduced down in heat from its initial setting.

ELECTRODE. The part of the welding machine that comes in contact with the parts to be welded. The electrodes are manufactured from a copper alloy that has good resistance to heat deformation while still having a good conductivity.

FLASH BUTT. This type of resistance welder is used to butt weld sections where the cross sectional area is to large for normal butt welding and the flashing of the weld acts as a sort of preheating function before the parts are plunged together.

FOOT SWITCH. The foot switch is a foot operated switch that the operator can use to start the machine electrically 

FOOT PEDAL. The foot pedal is normally fitted to the foot operated machine and is part of a mechanical system using levers to place pressure on the weld area.

FEED BACK COIL. This is a sensor coil used in constant current timer controls that is placed around the secondary circuit or arm of the welder. It senses the magnetic field and sends back this information to the timer system. Also know as a toriodal or Rogowsky coil.

HEAT. This refers to the amount of current or amps passing through the weld area.

HIGH LIFT. Where a cylinder or lever is used that lifts the welding tips to a secondary position allowing a larger opening between the tips. This position is not normally part of the welding stroke.

HIGH OR MEDIUM FREQUENCY. A system where the input frequency into the transformer (normally 50hz) is changed and increased. This allows for a smaller transformer being able to put out more welding power for its size than a transformer using the standard 50hz supply.

HOLD. Once the weld is complete a period of time must be allowed to let the molten metal dry before the welding tips open.

IGNITRON. This was the old method on switching electrical power on & off to the transformer. This system has been replaced by the thyristor, S.C.R switch.

OFF TIME. Timers used in the repeat (or stitching) mode need a delay timer period after the weld is completed to when the next welding sequence is started 

PHASE HEAT. The control method used in most timer systems to increase and decrease the amount of heat or current passing through the weld area.

PLATEN, the top and bottom jaw of a projection welder. The platens are normally “T” slotted to allow different electrode layouts to be mounted and used.

PRE-SQUEEZE. An adjustable timer period introduced on some timers that is prior to the squeeze time. This is used in machines where high lift of other functions like a motor start are present during the welding process.

PRESS BUTTON. These are fitted to portable welding guns, both manual and integral types, to start the weld sequence.

PRESSURE. In the context of resistance welding this is what pressure is achieved between the welding tips i.e. Tip Pressure. It can also refer to the air pressure being fed into the system i.e. Line Pressure or the regulated air pressure being fed from the F.R.L. unit to the air cylinder.

PRIMARY. This is normally associated with the input side or  the electrical supply to the transformer.

PROJECTION WELD. This machine uses flat electrodes or tips that cover the parts being welded. One part of the parts in the assembly to be welded has dimples pressed into it and these dimples localize the welding heat / current at the point where the  parts touch.

PULSATION. The ability of the timer to pulse the weld area multiple times. Weld pulsing normally has one weld setting that is used several time over.

P.F. or Power factor. This is where the balance between the timer control system and the transformer is set to ensure optimum output or efficiency of the system.

REPEAT. The ability of the timer to repeat the welding process as long is the start switch is held on or in the on position.

RETRACT. Where a cylinder or lever is used that lifts the welding tips to a secondary position allowing a larger opening between the tips. This position is not normally part of the welding stroke.

ROGOWSKY COIL. See feed back coil

S.C.R. Silicon controller rectifier, see AC switch and thyristor switch. This is the device that controls electrical flow to the transformer 

SEAM WELDER. This machine uses copper electrode discs that rotate during welding. As the discs rotate the timer system pulses the transformer allowing a stitch type weld to take place at the point of contact between the discs. This type of machine is commonly used in tank and automotive fuel tank manufacture.

SOLENOID VALVE. The air valve that controls the air flow to and from the welding cylinder used to open and close the welding tips.

SOLENOID COIL. The electrical coil that is fitted to the air solenoid valve. This electric coil is switched or controlled by the timer system to operate the solenoid valve 

SQUEEZE. The time a welding timer allows for air to flow from the solenoid valve to the cylinder, fill the cylinder with air, close the tips and build up pressure between the welding tips before welding commences.

SECONDARY. This is normally associated with the output side of the transformer or the arm / tip side of a resistance welder 

SPOT WELD. The most common resistance welding process so call due to the finished weld looking like a round spot.

THYRISTOR.  See also S.C.R. (Silicon controller rectifier), AC switch. This is the device that controls electrical flow to the transformer

TORIODAL COIL. See feed back co

TRANSFORMER. This device that converts electrical power in this case from high voltage (380Volts in S.A) and low amperage (80 – 200amps) to low voltage (5 – 25volts) and high amperage (5000amps – 50 000amps). These are fitted internally in the machine rame.

TIMER. The device that controls the welding functions such as squeeze, weld, hold and off times, the operation of air cylinders and the interface between the operator and the machine.

THERMOSTAT. The sensing unit that watches for heat build up in the system and switches the machine off should it detect an abnormal rise in the heat within the machine 

UPSLOPE. The ability of the Timer to slowly increase the heat / current passing through the weld area during the first three or four cycles of the welding process 

WATER COOLED. Water is used as a cooling agent within the welding system to remove heat from the tips, thyristor and the transformer. These items are referred to as being water cooled.

WELD ON/OFF. A switch available either on the machine or one the timer to allow the machine to function without allowing weld current to pass through the tips. This function is normally used during the tip dressing to allow the tips to open and close without welding 

ZERO CROSSING. The point on an AC sine wave where the voltage changes from positive to negative or visa versa.  

Abbreviations used in resistance welding 

%                     Percentage

AC                   Alternating Current

CuCrZr           Copper Chrome Zirconium

CuCr               Copper Chrome

CuBe              Copper Beryllium

BSP                 British Standard Pipe

DC                   Direct Current

EMF                Electromagnetic Field

FRL                 Filter, Regulator, Lubricator

Hz                    Electrical Supply Frequency in Cycles / Sec

Kg                   Kilogram

KVA                Kilo Volt Amps

L/min              Liter per Minute

MT1                Morse Taper Number One

MT2                 Morse Taper Number Two

Psi                   Pounds per Square Inch

RMS                Root Mean Squared

SCR                 Silicon Controlled Rectifier

Sqz                  Squeeze

I hope this was of some help to you. There are many publications that give a more in-depth study of terminology. Should you need a bit more help understanding any of the above we are only a phone call away and will try our best to help.

Introduction to Words and Terms

There are a lot of words that are used to explain functions and facilities used on a resistance welding, spot welders and their timers so let have a look at some of them. Please note this is a generalization of words / terms meant to help those new to this industry, not an in depth study of what each word or term means so please understand that...

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