Welding Process & Current Measurement Challenges
For a welding process to be successful, the two parts to be welded must be exposed to an intense heating source usually created with an electrical arc, the temperature of which can reach up to 3000°C. The quality of the welding depends, among other factors, on high control of this electrical arc and of the electrical current used to produce it. LEM current transducers measure this current, contributing to the control and proper function of the welding application.
Enhance Welding Efficiency and Safety with LEM Current Sensors
LEM provides current sensors specifically designed for various welding applications. These sensors play a crucial role in ensuring the efficiency, safety, and quality of these applications. Typical applications for industrial welding include:
- Power supplies for welding
- Power supplies for plasma welding
- Plasma cutting
- Electrolysis
- Inductive heating
HOB Series: High-Performance Closed-Loop Transducers
The HOB series represents LEM’s high-performance closed-loop Hall-effect current transducers designed specifically for demanding applications such as welding, plasma cutting, and SiC-based power supplies. These transducers combine fast response time with excellent accuracy.
HOB Series — Key Features
- Response time: < 200 ns (market-leading)
- Bandwidth: up to 1 MHz
- Accuracy: ±0.2% of IPN at +25°C
- Linearity: < 0.1%
- Di/dt follow: > 200 A/μs
- Operating temperature: -40°C to +85°C
SiC MOSFET and Wide Bandgap Applications
The adoption of Silicon Carbide (SiC) MOSFETs in welding power supplies has introduced new challenges for current measurement. SiC devices switch at much higher frequencies than traditional IGBTs, requiring current sensors with exceptional bandwidth and response time.
Why HOB is Ideal for SiC Applications
The HOB series was specifically designed to address the measurement challenges of SiC-based power electronics. With a bandwidth of up to 1 MHz and response time under 200 ns, HOB transducers can accurately capture the high-frequency current waveforms generated by SiC MOSFET switching. This enables precise closed-loop control of the welding arc, resulting in superior weld quality and energy efficiency.
Benefits for Welding Power Supply Manufacturers
By using HOB transducers, welding power supply manufacturers can fully leverage the advantages of SiC technology: smaller passive components, higher efficiency, and better dynamic response. The accurate current feedback enables tighter control loops, reducing arc instability and improving weld consistency.
Typical Welding Applications
LEM current sensors are deployed across a wide range of welding and related applications:
- Plasma arc welding: precise arc current control for high-quality welds
- Plasma cutting: monitoring cutting current for optimal cut quality
- Resistance welding: measuring welding current for quality assurance
- Inductive heating: controlling heating current for surface treatment
- Electrolysis: monitoring process current for efficiency optimization
