Manufacturer part number: W7200-E-SD-SD
Availability: 1 in stock
Manufacturer: MHWIRTH

BRAKE, CURRENT, EDDY, MODEL 72, 96,000-117,000 ft-lb, MHWIRTH P/N W7200-E-SD-SD

Key features
• The Model 72 Eddy Current Brake is a drawworks auxiliary brake designed to absorb a certain amount of torque at a given speed.
• The Model 72 Eddy Current Brake is a drop in replacement for a model 7838 brake.
• The Model 72 Eddy Current Brake rotor web is designed to resist pull over to reduce drag and increase unit life.

Braking capacity @ 50 RPM: 96,000 ft-lbs (130,159 nm)
Braking capacity @ 150 RPM: 117,000 ft-lbs (159,159 nm)
Maximum speed: 600 RPM
Coolant max. flow rate: 150 GPM (570 l/min)
Total brake resistance: 3.4 – 4.1 ohms
Resulting current @ 250 VDC 20° C ambient: 74 amps
Total heat rejected @ Full load: 4.9 MBTU/hr (1,420 kW)

Design data
Maximum inlet temperature: 104° F (40° C)
Maximum outlet temperature: 165° F (74° C)
Temperature class: T3

Classification society: None
Hazardous area classification: Zone 2

CE marking
CE marking: Yes
Products for explosive atmospheres - certification standards
Explosion protection standard: ATEX 94/9/C

Technical data
Depth (including shaft): 1478 mm (58.2 in)
Width: 1993.9 mm (78.5 in)
Height (including lifteyes): 2102.2 mm (82.8 in)
Air Gap: 0.055 in – 0.065 in (1.40 mm – 1.65 mm)

Weight: 12,927 kg (28,500 lb.)

Brake Housing
Housing Material: Carbon Steel
Primary Drain Connections: 4 in NPT
Primary Drain Connections: 2
Other Drain Connections (For Draining for Storage): ½ in NPT Plugged
Other Drain Connections: 1
Ground Type: Stainless Steel Primary Earth grounding Lug

Center Plates
Water/Coolant Inlet Port: 2 in NPT
Inlet Connections: 2 (1 per plate)
Breather Vent: 1/2 in NPT
Breather Vent Connections: 4 (2 per plate)
Overflow Port: 1-1/4 in NPT
Breather Vent Connections: 2 (1 per plate)

Material: Heat Treated 4340

Magnet Assembly
Material: Heavy Allex insulated wire
Magnet per brake: 2
Coils per magnet: 2
Coil Resistance: 13.5 - 13.9 ohms

Brake Rotor
Material: Ultra low carbon, low alloy material

Scope of supply
1 - Brake Housing
2 - Brake Center Plates
1 - Shaft
2 - Magnet Assemblies
1 - Brake Rotor
2 - End Rings
1 - RTD Junction Box
1 - Power Junction Box

Technical Description
• The Model 72 Eddy Current Brake is a drawworks auxiliary brake designed to absorb 96,000 ft-lb [130,000 N-m] @50 RPM and 117,000 ft-lb [159,000 N-m] @150 RPM.
• The brake requires excitation of 0-250 Volts DC/0-75 Amps DC.
• The entire assembly has an ingress protection rating of IP56.
• The brake housing is carbon steel and is fitted with integral lift lugs for handling.
• Each shaft is provided with two keyways and a 1-1/4 inch per foot tapered end for installation of a customer supplied coupling hub.
• The magnet is formed of coils that are wrapped with an impregnated mica tape for additional ground wall insulation that allows them to have a 180º C temperature rise thermal rating.
• The magnet coil cavity is also optimized to drain accumulated moisture via drain and vent pipes that are constructed with stainless material to prevent corrosion.
• The brake rotor web is also designed to resist rotor pull over and by reducing this pull over effect the rotor is less likely to drag against the magnet surfaces thus increasing the units’ life cycle.
• The Brake assembly and all major components are manufactured to be interchangeable with 7040 brake model assemblies and components.

Utility requirements
Electrical requirements
Voltage: 250 VDC
Current: 74 amps
Power consumption: 18.5 kW

Design features
Special focus on ergonomics, noise, vibrations, chemical substances and products, illumination, indoor climate and outdoor operation

Documents Included:
User Manual: Electronic
Manufacturing Recording Book: Retained
Certificates / Statements: As applicable

Offshore painting / Surface Treatment: Aker MH standard SA16
Preservation / Packing: Aker MH standard KA05

Products specifications
Location: Houston
Condition: New