MIB-200A AC Inverter Welding Power Supply

Experience the benefits of an DC inverter power supply for microwelding without the expense and complication

DC Inverter power supplies have become popular due to their ability to precisely join small materials. Some users hesitate to purchase DC inverters because they require expensive specialized transformers with built-in rectifiers. Now Miyachi has developed an AC inverter power supply that has all of the advantages of a DC inverter, but can be used with a conventional AC transformer. This new power supply is the MIB-200A.

The AC inverter heats more efficiently

Phase control systems with SCR’s like conventional AC welders have off-time during the weld cycle. The MIB-200A has no off time so weld times can be shortened, resulting in less heat-affected area, and more attractive welds.


Existing equipment does not have to be replaced

Since the MIB-200A uses a conventional AC transformer, existing transformers or heads do not need to be replaced. Only the power supply has to be changed.Cost and time for retrofit is minimized.

Excellent for fusing applications

The MIB-200A features a high duty cycle rating for greater throughput.Used with the MM-720A or the MM-730A Miyachi displacement checkers, theMIB-200A can stop welding at a preset electrode displacement (InterruptFunction), thus penetration can be controlled. Stable fusing quality and constant penetration are possible.

Output frequency is variable

AC frequency can be set in 16 steps from commercial frequency up to250 Hz. Using this function, weld times can be shortened compared to conventionalAC welders.



  1. The AC inverter has greater heat efficiency than single-phase AC welders so better quality welds with less splash are achieved.
  2. Picture 1 shows a conventional single phase AC output. Current level drops to zero at every half cycle. Also, there is cool time, (t2 and t4) for phase control.

    The MIB-200A AC inverter has no cool time for phase control or zero level, so weld current is supplied continuously. Picture 2 shows the intermittent temperature output of a conventional AC welder. The conventional AC weld has a higher peak current which causes weld splash. The AC inverter increases temperature linearly and supplies stable welding heat without creating peaks. For this reason, better heat efficiency, less splash and greater weld quality are possible.

  3. The AC inverter reduces electrode wear
  4. Picture 3 shows an application of a battery tab weld. Using a DC inverter, current flows in only one direction as shown in picture 3-1. Due to the directional current flow, heat distribution to the electrodes is uneven.One electrode wears faster than the other. Using the AC inverter, weld current flows through both electrodes alternately as shown in picture 3-2,thus heat is generated equally. Using the MIB-200A, asymmetrical electrodewear can be avoided and greater weld quality can be obtained even in series welds.

  5. The MIB-200A, AC inverter reduces insulation burning in fusing applications.
  6. The MIB-200A, AC Inverter wave form, picture 2, allows the user to precisely control the heat into the fusing material. This improved process control can lead to a reduction in the total amount of heat required to fuse, reducing or eliminating discoloration of the commutator and excessive burning of the insulation typically associated with too much heat.


How the unit fits into a microwelding total system:

MA-627A Remote Program Unit(Optional)

This optional remote control boxis used to store weld schedules and program multiple units.

  • Programing Functions:
    • Timer Settings
    • Weld Current
    • Current Monitor Limits
  • Display Functions:
    • Weld 1 and 2 Programmable
    • Weld Current, Voltage, and Time-Monitoredvalues
    • Trouble Data and Error Codes


  • CURRENT MONITOR (current high/low) 0.00~9.99kA 15 schedules (Monitoris turned off, if set to 00.0kA)
  • VOLTAGE MONITOR (voltage high/low) 0.00~9.99V 15 schedules (Monitoris turned off, if set to 00.0V)
  • COOLING SYSTEM Forced Air Cooling
Input Power:3-phase 480/440/400/380/240/220VAC
+10% -15%, common to 50Hz and 60Hz
Output Frequency:Frequency of welding current can be selected as per the chart below:
Control Method:200A (Peak Value) Duty Cycle:8%
Control Method:Primary Constant Current peak value control
Weld Schedules:15
Time Settings:Squeeze Delay:0-9999ms
Upslope 1, 2:0-99.5 cycles
Weld 1, 2:0-99.5 cycles
Down slope:0-99.5 cycles
Cool:0-99.5 cycles
Off:10-9990ms (10ms step settings)
Pulsation:1-9 times
Current Setting Range:0.10 ~ 9.99kA
Current Monitor:0.00 ~ 9.99kA 15 schedules
(current high/low)Monitor is turned off if set to 00.0kA
Voltage Monitor:0.00 ~ 9.99V 15 schedules 
(voltage high/low)Monitor is turned off if set to 00.0V
Cooling System:Forced Air Cooling
Weight:33 lbs. (15 Kg)


For more information, or help selecting or pricing a controlssystem, feel free to contact T. J. Snow.