Hydraulic-Powered Scrap Magnet Integration for 70,000 lb Excavators

[MikePhua]

Scrap Handling and Magnet Evolution in Heavy Equipment
Hydraulic-driven magnets have become essential tools in demolition, recycling, and scrap yard operations. Mounted on excavators, these magnets allow operators to lift, sort, and load ferrous materials with precision and speed. For machines in the 70,000 lb class—such as large excavators from Caterpillar, Komatsu, or Volvo—the integration of a hydraulic magnet must balance lifting capacity, hydraulic flow, and electrical conversion.
Traditional magnets relied on diesel generators or auxiliary power units mounted on the machine. These setups were bulky, maintenance-intensive, and prone to failure in harsh environments. The shift toward hydraulic-powered magnets simplified installation and improved reliability, especially for machines already equipped with auxiliary hydraulic circuits.
Terminology Annotation

• Hydraulic Magnet: A lifting magnet powered by hydraulic flow, using a generator or converter to produce DC current for magnetization.
  
• Excavator Auxiliary Circuit: A secondary hydraulic line used to power attachments like thumbs, hammers, or magnets.
  
• Magnet Controller: An electronic unit that regulates magnet activation, demagnetization, and safety timing.
  
• Demag Cycle: A brief reverse current pulse used to release material from the magnet quickly and cleanly.
  

Sizing and Compatibility for Large Excavators
A 70,000 lb excavator typically supports magnets in the 36" to 48" diameter range, depending on boom reach and material density. Key parameters include:

• Hydraulic flow requirement: 20–40 GPM
  
• Operating pressure: 2,500–3,500 psi
  
• Electrical output: 230–250 VDC
  
• Magnet weight: 2,000–3,500 lbs
  
• Lift capacity: 6,000–10,000 lbs of scrap steel
  

Before installation, technicians must verify:

• Auxiliary hydraulic circuit availability and flow rate
  
• Return line routing and cooling capacity
  
• Electrical interface for magnet controller
  
• Mounting bracket compatibility with quick coupler or pin-on setup
  

In one Midwest scrap yard, a Komatsu PC360LC was retrofitted with a hydraulic magnet system. After calibrating flow and installing a pressure-compensated valve, the machine lifted entire car bodies with ease, reducing cycle time by 40%.
Hydraulic Generator and Control Integration
Hydraulic magnets use a hydraulic generator—also called a hydraulic-driven alternator or converter—to transform fluid power into electrical current. This unit is mounted near the boom base or on the stick, depending on space and hose routing.
Installation steps:

• Mount generator securely with vibration isolators
  
• Connect pressure and return lines from auxiliary circuit
  
• Wire magnet controller to cab switch or joystick button
  
• Install fuse and relay protection for electrical system
  
• Test magnet pickup and demag cycle under load
  

Some systems include a soft-start feature to prevent hydraulic shock and extend magnet life. Others offer programmable demag timing to optimize release speed.
Operational Tips and Field Recommendations
To maximize magnet performance:

• Warm up hydraulic system before heavy lifting
  
• Avoid prolonged magnet activation without load
  
• Use demag cycle consistently to prevent material buildup
  
• Monitor hydraulic temperature during extended use
  
• Clean magnet face regularly to maintain pickup efficiency
  

In one demolition project, an operator used a 48" hydraulic magnet to clear rebar from a collapsed parking structure. By alternating magnet and grapple use, the team reduced cleanup time by two days and recovered over 20 tons of steel.
Maintenance and Troubleshooting
Common issues include:

• Weak pickup due to low hydraulic flow
  
• Magnet not releasing material (demag failure)
  
• Overheating of hydraulic generator
  
• Hose leaks or connector fatigue
  
• Electrical faults in controller or cab switch
  

Solutions:

• Check hydraulic filter and flow restrictors
  
• Inspect magnet face for wear or debris
  
• Test voltage output from generator under load
  
• Replace worn connectors with sealed Deutsch plugs
  
• Update controller firmware if available
  

Some operators install inline pressure gauges and flow meters to monitor magnet performance in real time.
Conclusion
Hydraulic-driven magnets offer powerful, efficient scrap handling for large excavators. With proper sizing, installation, and control integration, they transform a standard machine into a high-productivity material handler. In scrapyards, demolition zones, and recycling centers, the magnet is more than an attachment—it’s a force multiplier. When powered by clean hydraulics and smart electronics, it turns steel chaos into organized profit.