Intertron Model 301B

3 Phase Frequency Converter and 3 Phase Rectified D.C. Resistance Welding Controller

Pictures of the 301B
Installed on a Machine

Remote Control Panel
(Mounted beside the Welder Face)

The Complete Setup

  • Unmatched Versatility
  • Programming in English. “No Codes Required”
  • 6 Months Memory Retention Without Power
  • Electronic Air Pressure Control
  • Programmable Slope Synthesizer
  • 3 Phase Line Voltage Compensator
  • 140 Weld Schedules Data Retention
  • Multiple Foot Switch Pedal Operation
  • Program Integrity Secureable by a Lock and Key Control
  • Data Storage on PC (optional)
  • Serial Interface to Other Computers (optional)
  • Interface With Automation Equipment (optional)
  • Intertron Scanner (optional)
  • Motor Control with Wheel Encoder Feedback (optional)
  • 9 Channel Data Acquisition System (Model 304A, optional)

Welder controller cabinet with locking key, and containing the following:

  • 1 Monolithic front panel with a display of 68 digits and touch keypads with visual tactile feedback.
  • 1 Display front panel printed circuit board.
  • 1 Processor printed circuit board, containing the microprocessor, associated memory with battery backup, parallel and serial I/O ports, variable baud rate, cassette interface circuits, visual INPUT/OUTPUT diagnostics, computer memory diagnostics, independent 3 phase line voltage monitoring and compensation, and the voltage generators for programming WELD and FORGE pressure.
  • 1 Peripheral interface printed circuit board, containing the internal power supplies, the solid state relays for valve solenoid operation, the INTERTRON transceiver, and the SCR/IGNITRON pulse amplifiers.
Physical Specifications:
  • Input voltage and power consumption: 220/240/440/480 VAC 60 HZ – 15 watts
  • Operating temperature: 0 to 60 degrees Centigrade
  • Weight: 24 lbs.
  • Physical Dimensions: 12 1/4″h x 20 1/2″w x 6 1/2″d
Standard Features:
  • Control Features:
    • Weld / No Weld, Repeat / One Shot, Tip / Wheel Dress, Foot Switch Lock, Motor ON and 110VAC/30VA Outputs for controlling up to seven valve solenoids and relays
    • Water Saver Timer. Shuts itself off when head is raised.
    • Tip Arc Relay Control
    • Two Stage Foot Switch Inputs, direct connection up to four foot pedals
    • Interrupt input to halt control and sound internal alarm if detects overheating, no water flow, or lack of adequate air pressure. (Detection devices not included.)
    • Line Voltage Compensator manual override
    • Programmable Slope in all three modes for generating complex heat wave forms
    • Weld schedule program under key lock. (Operator can still vary % heat ±5% of previous heat setting.)
    • Internal switch (jumper) selects Frequency Converter of Full Wave Rectified D.C. operation.
    • Thumb wheel switch for instantaneous selection of 140 preprogrammed weld schedules, with all variables parameters as viewed on the front panel
  • Weld & Forge psi display: 00-99
  • Operating Modes: SPOT – SEAM – ROLL (intermittent drive)
  • Fixed timing functions, Tip travel 20 cycles, Precompression 4 cycles
  • Variable timing functions:
  • SQUEEZE0-99 
    PREHEATImp. - Cool - Heat - Heat % -
    Heat decay - Heat decay %
    WELDImp. - Cool - Heat - Heat % -
    Heat decay - Heat decay %
    POST HEATImp. - Cool - Heat - Heat % -
    Heat decay - Heat decay %
    TEMPERImp. - Cool - Heat - Heat % -
    Heat decay - Heat decay %
    FORGEHi - Low - Var. Delay Start000.0-999.9 
  • Standard components supplied with each system:
    • Welder controller cabinet
    • Power distribution transformer
    • Ignitron firing modules, or SCR firing modules
Optional Features and Components:
  • RS 232 Interface for downloading, storing, and editing weld schedules on a PC.
  • Interlock Scanner. It interlocks the operation of up to ten controllers per scanner for sequential welding.
  • Interface for control from a central computer.
  • SCR firing package
  • IGNITRON firing package
  • Motor control with wheel surface speed encoder feedback
  • Model 304A Data Acquisition System
  • Model 350A Electronic Air Pressure Controller
Intertron Products:
Single Phase:

100 | PC100 | 105 | 108

109A | IN200/300 | 375 | 1000

Three Phase:

301B | 302A | 302C | 375

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Model 304 Monitor

Model 350A Electronic Air Pressure Controller

Electronic Air Pressure Controller with dual outputs, for supplying pilot air pressure to WELD and FORGE air pressure regulators.


  • Operating range: 05 psi to 90 psi
  • Resolution and Accuracy: ±0.5 psi
  • Input air pressure: 120 psi typical
  • Physical dimensions: 10″ x 3″ x 10″ (H x W x D)
  • Weight: 14 lbs.