The Rexroth PSI63C0.620L1 and its variants like the PSI63C0.737L1 (Part Number 107091446) are high-performance medium-frequency (MF) welding control inverters. These units are part of the Bosch Rexroth PSI 6000 series, designed specifically for resistance welding applications in highly automated production lines. By converting standard line frequency into a 1000Hz medium-frequency output, these inverters provide superior control over the welding current, resulting in higher quality joints, reduced energy consumption, and longer electrode life compared to traditional AC welding systems.

Product Technical Description

The PSI63C0 series utilizes advanced IGBT (Insulated Gate Bipolar Transistor) technology to provide a high-speed, regulated current output. The inverter functions by rectifying the three-phase AC input into a DC bus and then “chopping” it at a high frequency (1kHz) through a welding transformer. This allows for millisecond-level precision in current regulation. The unit features integrated I/O for communication with PLC systems via Fieldbus (such as Profibus, Profinet, or DeviceNet) and includes sophisticated monitoring for “U-I” (Voltage-Current) regulation to compensate for material variations during the weld nugget formation.

 

Product Datasheet & Parameters

• Model Series: PSI 63C0 (Medium Frequency)
• Part Number: 107091446 (Standard variant)
• Nominal Power: 60 kVA to 80 kVA (Depending on cooling and duty cycle)
• Input Voltage: 3-Phase 400V – 480V AC (+10% / -15%)
• Output Frequency: 1000 Hz (1 kHz)
• Maximum Welding Current: Typically up to 20kA (depending on transformer ratio)
• Cooling Method: Water-cooled (requires consistent flow rate for high duty cycles)
• Communication: Modular Fieldbus Interface (Profibus/Profinet/Ethernet IP)
• Protection Rating: IP20 (intended for cabinet mounting)
• Internal Memory: Storage for up to 256 welding programs (sequences)

 

Country of Origin

This welding control inverter is manufactured by Bosch Rexroth AG in Germany.

 

Application Fields

• Automotive Body-in-White: High-speed spot welding of vehicle frames and galvanized steel sheets.
• Aerospace Manufacturing: Precision resistance welding of aluminum and specialized alloy components.
• Battery Production: Micro-welding of battery tabs and busbars for EV battery packs.
• Appliance Manufacturing: Automated assembly of stainless steel cabinets and drums for white goods.
• Electronics: Precise thermal compression bonding and small-scale component welding.

 

Product Usage Instructions

The PSI63C0.620L1 must be installed in a clean, dry control cabinet with sufficient clearance for electrical connections. Ensure that the water-cooling circuit is connected and bled of air before applying power; operating the unit without proper coolant flow will lead to immediate IGBT failure. All high-current secondary cables should be kept as short as possible to minimize inductive losses. Programming of the weld schedules (squeeze time, weld time, hold time) is typically performed using the Rexroth “Weld-as-Assistant” or “BOS-6000” software interface.

 

Common Questions & Answers (Q&A)

Q: What is the main advantage of 1000Hz welding over standard 50/60Hz AC welding? A: The 1000Hz frequency allows for much faster adjustment of the welding current (every 1ms), which leads to more stable heat input, less spatter, and the ability to weld complex materials like aluminum or high-strength steel more effectively.

Q: Can this inverter be air-cooled? A: The PSI63C0 series is primarily designed for water cooling to maintain its compact power density. While low-duty applications might exist, standard automotive and industrial use requires a closed-loop water chiller system.

Q: How do I troubleshoot a “Current Not Reached” alarm? A: This usually indicates an issue in the secondary circuit. Check for worn electrodes, loose cable connections, or a failing welding transformer. Also, verify that the primary line voltage is not sagging during the weld pulse.

Q: Is the firmware compatible across the 620L1 and 737L1 models? A: While the power stages are similar, the control firmware may vary based on the specific Fieldbus module installed. Always back up your welding parameters before attempting a hardware swap.

 

Similar Model Recommendations

1. Rexroth PSI63C0.600L1
2. Rexroth PSI63C0.700L1
3. Rexroth PSI6100.100L1
4. Rexroth PSI63C0.737L1 (Alternative Revision)
5. Rexroth PSG 6000 Series Transformers (Matching components)