Elmagco 7838 Drawworks Brake

Elmagco 7838W Brake — Specification Sheet

General Information

• Manufacturer: NOV / Elmagco Baylor

• Model: 7838W

• Type: Eddy-current / electromagnetic brake

• Cooling: Water-cooled

Electrical / Brake Excitation

• Input Voltage (DC): ~ 250 VDC

• Input Current (at ~20-25 °C): ~ 74 A

• Coil Configuration: 2 magnets, 2 coils per magnet

• Coil Internal Resistance @ 20 °C: ~ 13.4-13.9 Ω (later versions) / ~ 11.0-11.5 Ω (earlier versions)

Duty / Performance

• Maximum RPM: ~ 600 rpm

• Maximum Torque @ ~150 rpm: ~ 117,000 lb-ft (~ 158,600 N·m)

• Torque @ ~50 rpm: ~ 96,000 lb-ft (~ 130,200 N·m)

• Power Input (at coil temp 68 °F / 20 °C): ~ 18.5 kW (later versions) / ~ 22.3 kW (earlier versions)

Cooling Specifications

• Minimum Coolant Flow (Brake inlet): ~ 150 GPM (~ 568 L/min)

• Max Coolant Inlet Temperature: ~ 100 °F (~ 38 °C)

• Max Coolant Discharge Temperature: ~ 165 °F (~ 74 °C)

• Cooling Water Piping: Inlet: (2) 2-in NPT; Outlet: (2) 4-in NPT; Overflow: (2) 1¼-in NPT

Mechanical / Physical

• Weight: ~ 28,000 lbs (~ 12,701 kg)

• Shaft & Rotor Weight: ~ 6,458 lbs (~ 2,929 kg)

• Inertia (WK²) of Shaft + Rotor: ~ 37,938 lb-ft² (~ 15,987,118 kg·cm²)

• Shaft Diameter: ~ 7.50 in (~ 190.5 mm)

• Taper of Shaft: ~ 1.25 in per foot (~ 31.75 mm per 305 mm)

• Overall Height: ~ 78 in (~ 1,981 mm)

• Overall Width: ~ 38 in (~ 965 mm)

Ambient / Environmental Conditions

• Maximum Ambient Temperature: ~ 50 °C