Medium Frequency Inverter DC Resistance Welding Controller | MFDC Spot Welding Control Unit

Resistance Welding Machine Products

Medium Frequency Inverter DC Resistance Welding Controller

Core Advantages vs Traditional 50/60Hz AC Line-Frequency Welding Machines

1. Control Performance

• Traditional line-frequency AC welders adjust transformer secondary output via thyristor firing angle. Direct grid connection leads to low power factor, long 20ms adjustment cycle under 50/60Hz mains.
• Our medium-frequency inverter DC controller converts 3-phase AC to DC, then IGBT inversion feeds power to welding transformer. It runs at 1kHz inverter frequency with only 1ms adjustment response—20x faster than conventional units. Higher control accuracy, quicker response and ultra-stable output are guaranteed.

2. Power Grid Adaptability

• Traditional AC spot welders adopt single-phase 380V input, causing severe 3-phase unbalance, low grid utilization, high reactive power and grid harmonic pollution. Multiple units require large capacity transformers and raise customer investment cost.
• IDW MFDC controller uses balanced 3-phase 380V input with full-wave rectification, power factor above 90%, balanced current across three phases and minimal grid interference.

3. Welding Current & Energy Saving

• Line-frequency AC generates zero-cross current gaps, scattered heat, unstable welding quality and heavy heat loss. Grid voltage fluctuation causes obvious current swing; secondary circuit inductance severely disturbs welding current.
• MFDC outputs continuous DC without zero crossing. Heat concentrates on welding spot to cut heat loss and shorten welding time for remarkable energy saving. No AC peak current reduces spatter and extends electrode service life. Secondary loop inductance barely impacts welding current and eliminates loop power loss.

4. Matching Transformer

• 50/60Hz line-frequency transformers are bulky, heavy and low-efficiency under same power rating.
• Matched 1kHz medium frequency transformers feature compact size, low loss and high efficiency for easy installation.

5. Wide Material Compatibility

• Beyond above strengths, MFDC controllers support diversified welding schedules and fit all metals: coated steel, galvanized steel, stainless steel, aluminum and dissimilar metals, widely adopted across all metal processing industries.
• Core Controller Features
• Output inverter frequency: 1kHz–4kHz, millisecond-level timing precision
• Stores up to 32 groups of welding schedules, expandable to 256 groups
• 3-stage heating program: preheating, welding, tempering; customizable current ramp-up/ramp-down and cycle counts for welding stage
• 3 groups programmable I/O output ports, compatible with PLC, welding robots and automated lines
• RS485 & BCD code communication, connectable to industrial PC for remote control and centralized automatic management
• Real-time secondary current closed-loop feedback, current control accuracy up to 5‰
• Historical alarm record function for fast fault troubleshooting
• Complete Technical Parameter Table

Model	DW400L	IDW-600T	IDW-800T	IDW-1000T	IDW-1200T	IDW-1800T	IDW-2400
Inverter Mode	Medium Frequency DC
Input Voltage	3-phase 380V, fluctuation +10%/-20%, 50/60Hz±1%
Max Primary Output Current	400A	600A	900A	1100A	1300A	1800A	2400A
Matching MF Transformer	90KVA	120KVA	180KVA	200KVA	250KVA	350KVA	350KVA×2
Max Short-circuit Secondary Current	20KA	30KA	40KA	50KA	60KA	72KA	96KA
Matched Air Switch	100A	100A	125A	160A	160A	200A	400A
Current Adjustment Range	0–400A/0–20KA	0–600A/0–30KA	0–900A/0–40KA	0–1000A/0–50KA	0–1300A/0–60KA	0–1800A/0–72KA	0–2400A/0–96KA
Control Mode	Constant Primary Current / Constant Secondary Current
Solenoid Valve Output	Standard: 4 valves; seam welder version: 10 valves
Inverter Frequency	1kHz / 4kHz
Solenoid Valve Spec	DC24V±10%, single channel ≤0.15A
Communication Interface	RS485
Max Welding Schedules	32 groups, expandable to 256
Cooling Water Requirement	6L/min ≥0.15MPa ≤40℃	8L/min ≥0.15MPa ≤40℃	12L/min ≥0.15MPa ≤40℃
Working Temperature	Water cooling: -5℃ ~ 50℃
Ambient Humidity	≤80% RH
Max Working Altitude	1000m
Insulation Class	Class F
Cabinet Size	Standard size, customized available

• Full Welding Timing & Current Operating Parameters
• Timing Parameters (All Unit: ms, Range 0–9999 unless noted)
• Pre-pressure Time, Pressure Hold Time, Cooling Time, Hold Time, Idle Time: 0–9999
• Ramp-up / Ramp-down Time: 0–99
• Preheat Time, Welding Time, Temper Time: 0–999
• 3 Groups Independent Constant Current Control
• CC1 (Primary Constant Current): 0–9999A
• CC2 (Secondary Constant Current): 0–99.99KA

6. 7-inch Touch Panel Introduction

• Equipped with 7-inch industrial touch screen for parameter setting, function selection and real-time monitoring of welding current, capacitor voltage and running status. All operation steps can be finished directly on touch screen without extra controllers.

7. Operation Guide

• Working Screen: Automatically loaded after power-on; welding operation only available on this interface
• Parameter Setting Screen: Configure all welding timing & current recipes
• Function Setting Screen: Single/continuous welding, seam welding, primary/secondary constant current, water flow/temperature monitoring, electrode dressing, cyclic welding modes
• Application Scope
• Automotive sheet metal, household appliances, hardware parts, electronic components, galvanized steel, aluminum alloy, stainless steel, dissimilar metal spot & projection welding, matched with medium frequency welding transformers for full MFDC welding solutions.

Resistance Welding Machine Products