DC Inverter Power Supplies for Resistance Welding Applications

The DC Tech Series has been discontinued and is no longer available, please contact a service representative to discuss best options.

We are proud however to suggest some of our other items (Adobe Acrobat Format 444K) as a replacement. Please feel free to give our expert staff a call at any time. Putting our expertise to work for you, finding the right solution is just a phone call away.

For Spot Welding:

  • IS-120A
  • IS-444B
  • IS-471B
  • ISA-500A

For Seam Welding:

  • IS-443B
  • IS-470B

Typical Applications and Uses

For Spot Welding:

  • Stainless and galvanized doors and furniture
  • Automotive sheet metal and components
  • Aluminum structural components
  • Copper wire solidification
  • High Speed copper to galvanized cross wire welding
  • Motor Armature fusing

For Seam Welding:

  • Water filtration components
  • Vehicle fuel tanks
  • Aluminum and titanium aircraft components
  • Heavy gauge wire shelving
  • High speed bi-metal electrical contacts

Features

  • High Speed Adaptive Feedback
  • Process Control
  • Closed Loop Feedback
  • Technically advanced Inverter Technology
  • Shorter Weld Times

Benefits

  • Provides consistent, reliable welds with optimal nugget formation, superior joint strength, and excellent surface appearance.
  • Provides millisecond control over the resistance welding process
  • A feedback rate of every 500 microseconds actively maintains the programmed weld current or power
  • Improves spot and seam welding of traditionally “hard to weld” materials including coated steels, aluminum, brass, and copper.
  • Compared to conventional AC welders, DC Inverter technology produces heat more efficiently, thus decreasing weld times as much as 1/3rd and reducing the heat affected zone (HAZ).

Specifications: Spot Welder Power Supplies

Power Supply ModelIS-120AIS-444BISA-500AIS-471B
Power Source:3 phase 480VAC / 440 VAC / 20VAC +10% -15% 50/60 Hz
Output Frequency:1 kHz / 800 Hz / 600 Hz (selectable)
Output Voltage:Single Phase 650V, Peak at 480V input
Rated Capacity:52 kVA at 480 VAC182 kVA at 480 VAC325 kVA at 480 VAC
Maximum Primary
 Output Current:
200 A (8% duty cycle)500 A (15% duty cycle)1000A (12% duty cycle)
Control Systems:Secondary Constant Current Secondary Constant Current 
Secondary Constant Power Secondary Constant Power 
Primary Constant Current (RMS) Primary Constant Current (RMS) 
Primary Constant Current (Peak) Primary Constant Current (Peak) 
Fixed Pulse Fixed Pulse
Secondary Constant Voltage
Control Modes:N/AForging, Chaining, 
 Successive
N/A
Weld Schedules:15 schedules
Timer Settings:ms Mode ms Mode Cycle Mode 
   Squeeze Delay 0000-9999 ms 0000-9999 ms 000-999 cycles 
   Squeeze 0000-9999 ms 0000-9999 ms 000-999 cycles 
   Weld 1 000-600 ms 000-600 ms 00-30 cycles 
   Upslope 000-400 ms 000-400 ms 00-20 cycles 
   Cool 000-999 ms 000-999 ms 00-99 cycles 
   Weld 2 000-600 ms 000-600 ms 00-30 cycles 
   Downslope 000-400 ms 000-400 ms 00-20 cycles 
   Hold 000-999 ms 000-999 ms 00-99 cycles 
   Off 0000-9999 ms 0000-9999 ms 00-99 cycles 
   Pulses1-9
and Cycle Mode (see right)
1-9 1-9 
Maximum Secondary
Current Settings:
0.1 -- 20.0 kA2.0 -- 40.0 kA4.0 -- 80.0 kA
Weld Monitors:
   Current 00.0-20.0 kA 00.0-40.0 kA 00.0-80.0 kA 
   Voltage 00.0-9.99 V 00.0-9.99 V 00.0-9.99 V 
   Power  00.0-20.0 kW 00.0-40.0 kW 00.0-80.0 kW 
   Pulse Width10%-100%10%-100%10%-100%
Program Unit:MA-627A (sold separately)
Monitor Unit:MA-628A (sold separately)
Dimensions
(H x W x D):
11 x 7 x 25 inches 
(686 x 483 x 1600 mm)
27 x 12 x 20 inches 
(1702 x 762 x 1295 mm)
27 x 12 x 26 inches 
(1702 x 762 x1664 mm)
Weight:33 lbs. (15 kg)99 lbs. (45 kg)139 lbs. (63 kg)

Specifications: Seam Welder Inverter Power Supplies

Power Supply ModelIS-433BIS-470B
Power Source:3 phase 480 VAC  /  440 VAC  /  220 VAC  +10% -15%  50/60 Hz
Output Frequency:1 kHz  /  800 Hz  /  600 Hz (selectable)
Output Voltage:Single Phase 650V, Peak at 480V input
Rated Capacity:182 kVA at 480 VAC325 kVA at 480 VAC
Maximum Primary Output Current:500 A (15% duty cycle)1000 A (12% duty cycle)
Control Systems:Primary Constant Current 
(PWM RMS Value) 
Primary Constant Current 
(PWM Effective Peak) 
Fixed Pulse
Control Modes:N/A
Weld Schedules:7 schedules
Timer Settings: ms Mode 
   Squeeze Delay n/a 
   Squeeze 0000-9999 ms 
   Delay 000-999 ms 
   Weld 1 000-600 ms 
   Upslope 000-400 ms (included in Weld 1) 
   Cool 000-999 ms 
   Weld 2 n/a 
   Downslope n/a 
   Hold 000-999 ms 
   Off n/a 
   Pulses1-9
Maximum Secondary Current Settings:1.0 - 20.0 kA2.0 - 40.0 kA
Weld Monitors: 
   Current 00.0-20 kA 00.0-40 kA 
   Pulse Width10%-100%10%-100%
Program Unit:MA-627A (sold separately)
Monitor Unit:N/A
Dimensions (H x W x D): 27 x 12 x 20 inches 
(1702 x 762 x 1295 mm)
27 x 12 x 26 inches 
(1702 x 762 x 1664 mm)
Weight: 99 lbs (45 kg)139 lbs. (63 kg)

Specifications: DC Inverter Transformers

Transformer ModelIT-40IT-85IT-130IT-250
Rated Capacity:40 kVA at 50%85 kVA at 50%130 kVA at 50%250 kVA at 50%
Maximum Input Voltage:650 V650 V650 V650 V
Input Frequency:1000 Hz1000 Hz1000 Hz1000 Hz
Unloaded Secondary
Voltage/Turns Ratio:
4.28 V (152:1) 8.9 V (73:1) 13.0 V (50:1) 13.0 V (50:1)
8.55 V (76:1)9.5 V (68:1)13.8 V (41:1)
Cooling Water:1 gal/min2 gal/min4 gal/min4 gal/min
Dimensions
(H x W x D):
6.75 x 5.0 x 14.85 in
 (432 x 330 x 965 mm)
6.75 x 6 x 11.9 in
(432 x 381 x 762 mm)
10.26 x 6 x 15.5 in
(660 x 381 x 991 mm)
10.25 x 7.75 x 19 in
(660 x 483 x 1219 mm)
Weight:60 lbs. (27 kg)60 lbs. (27 kg)110 lbs. (50 kg)130 lbs. (59 kg)

Inverter Welding Delivers Performance and Payback

Courtesy of Miyachi

With quality and production demands increasing, DC inverter resistance welding offers benefits that traditional AC welding cannot address. In the broadest sense, inverter welding offers more flexibility than conventional AC welding. Virtually any application that can be done with an AC weld control can be done with inverter technology.

Inverter Performance Benefits

Many resistance weld failures can be traced to inconsistent secondary welding current. Adaptive feedback systems used in inverter technology utilize pulse width modulation to continuously monitor and adjust the weld current throughout the weld, compensating for non-uniform workpiece resistance, worn electrodes, and power source fluctuations, resulting in extremely consistent weld current delivery throughout every weld. The benefits derived include shorter weld times, lower currents and forces, faster speed and throughput, longer electrode life, less weld splash, and less surface deformation of the part.

Efficient Weld Current Delivery Improves Quality

In resistance welding, a weld joint (or nugget) is formed as weld current flows through the workpieces, encountering different electrical resistanaces and generating heat. AC controls, by definition, cycle weld current on and off twice per cycle. The AC “cycling” can cause embrittlement and irregular nugget formation, hurting weld quality and strength. By contrast, inverter systems deliver current without cycling, thus continuously heating the weldments. Weld times can be adjusted in one millisecond increments. This precise control allows inverter welders to utilize shorter weld times and control how current can be introduced into the parts by “shaping” the current weldform. Lower weld current and less force (compared to AC weld controls) and be utilized to achieve the desired molten state of the weldments for optimal nugget formation.

Hard to Weld Materials

Inverters are capable of successfully welding a broad range of materials. Softer metals, particularly those with high electrical and thermal conductivity are good candidates for inverter resistance welding. Higher electrical conductivity means that higher weld currents must be used. High thermal conductivity requires that the weld current must be delivered quickly to minimize the heat affected zone. Zinc coated galvanized steels also fall into this category.

High Current Output – Small Transformer Package

Compact inverter equipment features small, lightweight welding transformers for use in manual, automated, and robotic (transgun) configurations. In AC resistance welding, higher current outputs generally require extremely large transformers. The physical size and weight of the AC welding transformer is especially critical in transgun configurations, often limiting the current output available. Inverter transformers are often as much as 50% smaller, lighter, and deliver higher current outputs than conventional AC transguns.

Inverter Realities

Inverter performance benefits can result in higher production rates with less time lost to electrode maintenance and changes. According to many manufacturers, weld failures, part rejects, and costly re-works have been dramatically reduced. Shorter weld times, lower weld currents, and balanced line loads, lessen the primary current demand – reducing electrical usage and expense. Adaptive feedback control modes and millisecond programming make precise control over the resistance welding process a reality. DC inverter welding allows for a broader process window to overcome workpiece variances and production changes. This larger process window is one of the primary reasons that inverter welding meets today’s demand for higher quality and delivers such an attractive return on investment.

DC inverter power supplies offer large benefits in some resistance welding applications. Offered in capacities of up to 325 kVA, dc inverter technology is able to deliver superior weld quality by using lower weld currents, shorter weld times, and lower weld forces than conventional AC controls. Through the use of a high speed control monitoring multiple weld functions using adaptive feedback, the user is able to regulate the welding process.

Superior control over current and heat generation results in a reduction in energy use and increase in electrode life, as well as improved weld quality, increased production efficiency, and reduced cost.

Closed Loop Feedback Control

A closed loop feedback system means that the control receives input as to how this particular weld is progressing and adjusts to maintain the weld at the entered specification. The control is able to maintain either weld current or power (user selected) by measuring and adjusting the secondary current and voltage. The control gets new feedback every 500 microseconds, consistent weld current (or power) at the electrodes is maintained, overcoming power fluctuations and workpiece material variances that hurt weld quality.

For more information, or help selecting or pricing a DC Inverter system, feel free to contact T. J. Snow. We will be glad to help in any way we can.

MA-627A
Remote Program Unit

Used to store weld schedules and program multiple units.

MA-628A Monitor Unit

Adds process security by displaying Current, Power, time and error data while inhibiting access to programming functions.

To put together a complete system you need the following separate components:

  • Inverter Power Supply (specs below)
  • Program Unit (MA-627A)
  • Toroidal Coil (the pickup for the feedback loop)
  • Inverter Transformer (selction table below)
  • Monitor Box — MA-628A (optional)

Transformer Selection Table

ModelIT-40IT-85IT-130IT-250
IS-120A (Spot)XXXX
IS-444B (Spot)XXXX
ISA-500A (Spot)XX
IS-471B (Spot)XXXX
IS-443B (Seam)XXXX
IS-470B (Seam)XXXX

Navigation