Brakes and Clutches
Blower-Cooled Hystersis Brakes

NEW! BHB Series Blower-cooled Hysteresis Brakes

SpecificationsSystem OptionsData Sheet

When torque control/torque measurement must be performed at the highest possible power, Magtrol BHB Series Hysteresis Brakes are ideal. This design allows for continuous power ratings up to 6000 watts (7000 watts intermittent). Use of pre-loaded bearings in the BHB Series Hysteresis Brakes allows operation at speeds of up to 20,000 rpm for extended durations.

BHB Brakes are conveniently base mounted. Base mounting, with integral barrier type terminal strip, provides easy mounting and wiring.

BHB Series Blower-Cooled Hysteresis Brakes
Note: Shown with T-Slot bast plate sold separately
Applications Features

Magtrol’s BHB Series Blower Cooled Hysteresis Brakes can function in either torque measurement or torque control applications. When mounted to a PT Series T-slot Base Plate, a cost-effective, basic motor test rig can be easily configured. For this purpose, Magtrol offers several accessories and system options to choose from. The simplest test bench may include one or two BHB Brakes and an AMF Adjustable Motor Fixture mounted onto a PT Base Plate. Adding a TM Series In-Line Torque Transducer, couplings, FRS Free-Run Speed Sensor, 3411 Torque Display or DSP7000 Controller greatly expands the system’s motor testing capabilities.

Other accessories available from Magtrol include: power supplies,pipe fittings, jack shafts and risers.

In addition to motor test applications, BHB Series Blower Cooled Hysteresis Brakes can be used for the following:
• Durability/reliability verification
• Brush run-in
• Carburetor tuning
• High-speed tension control

• Ideal for low-torque/high-speed applications with exceptional power ratings
• Torque: 3 N·m to 24 N·m
• Speed: up to 20,000 rpm
• Power: up to 7000 W
• Included blowers eliminate the need for additional air supply equipment
• Includes air deflectors to guide exhaust air away from the motor under test
• Magtrol hysteresis braking technology provides precise torque control independent of shaft speed
• EMC conforms to European standards
• All metric dimensioning
• Base mounting standard
• Designed for use with Magtrol’s PT Series T-slot Base Plate mounting system (sold separately)
• A variety of accessories and system options to choose from to create a simple and cost-effective test system

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For complete technical specifications, including power absorption curves, download the data sheet. For detailed dimension drawings… Calculators
Click on the icon in the table below. A PDF document will open in a new window.
(Adobe Acrobat Reader 7.0, or later, is required.)
Brake Ratings
Model Included Blower Minimum
Torque at
Rated Current
Kinetic Power View
Solid Model
With Blower
5 Minutes Continuous
Model Voltage N·m mA rpm W W PDF PDF STEP
BHB-3B BL-001 120 3 750 20,000 1,500 935
BHB-3BA BL-001A 240 3 750 20,000 1,500 935
BHB-6B BL-001 120 6 1,500 20,000 3,400 3,000
BHB-6BA BL-001A 240 6 1,500 20,000 3,400 3,000
BHB-12B BL-001 120 12 1,200 12,000 3,500 3,000
BHB-12BA BL-001A 240 12 1,200 12,000 3,500 3,000
BHB-24B BL-002 120 24 2,400 12,000 7,000 6,000
BHB-24BA BL-002A 240 24 2,400 12,000 7,000 6,000
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System Options
Click on the component name for more information. Scroll down for optional accessories.
Open-loop Systems
A characteristic of the open-loop system is that it does not use feedback to determine if its input has achieved the desired goal. This means that the system does not react to the output of the processes that it is controlling. An open-loop controller is often used in simple test setups because of its simplicity and low cost, especially in systems where feedback is not critical. Below is an example of an open-loop system.
BHB Open-Loop System AMF Adjustable Motor Fixture PT Series T-Slot Base Plate 5210 Power Supply TM In-Line Torque Transducers 3411 Torque Display

Closed-loop Systems
A characteristic of the closed-loop system is that it uses feedback to determine if its input has achieved the desired goal. This means that the system reacts to the output of the processes that it is controlling.
A closed-loop controller is often used because of its ability to repeatedly return to a desired controlled point. Below is an example of a closed-loop system.
BHB Closed-loop System TM In-line Torque Transducer DSP7000 Controller AMF Adjustable Motor Fixture PT Series T-slot Base Plate Laptop PC with M-TEST

Optional Accessories
TM riser TM Risers
Many times, the BHB Brake will be used with one of Magtrol’s TM Series In-Line Torque Transducers. Risers lift the appropriate TM from the PT to the shaft height of the brake. The riser is complete with attachment hardware for the TM and T-Nuts and shoulder bolts for attachment to a PT Base Plate.
Detailed dimension drawings

Jackshaft Jack Shafts
For each brake there is an appropriately sized hardened jack shaft, complete with T-Nuts and shoulder bolts, that will mount to a PT Base Plate.

PT Series Base Plate PT Series Base Plates
Used for creating a basic test rig by mounting a BHB Brake and/or TM Torque Transducer in line with the unit to be tested. Its solid, warp-resistant structure and multiple, single-sided T-slots enable modular construction that is cost-effective and easy to assemble.

AMF Series Adjustable Motor Fixtures AMF Series Adjustable Motor Fixtures
Used to secure small to medium-sized motors in place while running any test. These extremely versatile fixtures also enable easy motor centering for coupling to an BHB Brake. (Couplings can be supplied upon request.) The AMF-1, -2 and -3 Fixtures feature one or two adjustable bridges, each fitted with a fluted knob clamp screw, to allow clamping anywhere along the axis of the motor. To safeguard the motor, locking thumb screws provide protection against vibration and all motor-to-fixture contact surfaces are nylon padded for scratch-free clamping.

TM In-line Torque Transducers In-Line Torque Transducers
Deliver precise torque and speed measurement over a very broad range. Each model has an integrated conditioning electronic module providing 0 to ±10 V DC torque output and an open collector speed output. All TM In-Line Transducers employ Magtrol’s unique non-contact differential transformer torque measuring technology which makes them very reliable, providing high overload protection, excellent long-term stability and high noise immunity.

FRS Free-Run Speed Sensor
Designed for applications where it is necessary to acquire speed readings that are unaffected by drag load. Before connecting a motor to the dynamometer, the free-run speed can be obtained from the FRS Sensor. With its reflective sensor, the FRS does not need to be attached to the motor but only placed close to the motor shaft (as shown in the photo to the right). Note: For best contrast, the shaft should be marked with reflective tape. The sensing end of the fiber optic assembly emits and receives light reflected from the shaft, and sends the speed signal to the digital fiber sensor.

The raw speed data is then transmitted to either a Magtrol 3410 Torque Display or DSP7000 Dynamometer Controller where it is converted and displayed in rpm

Power Supplies
BHB Series Blower Cooled Hysteresis Brakes provide torque that is proportional to the current applied. During normal operation, the coil resistance of an BHB Brake will change with temperature. To eliminate the resulting torque drift, Magtrol recommends using a current-regulated power supply, such as the Model 5210, VM Series or the Lambda ZUP36-6.

Also Available: • Connection Cables: brake to controller; power supply to brake; controller to power supply
• Couplings: brake to in-line torque transducer
• Pipe Fittings
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Magtrol, Inc (USA): 716-668-5555 • ~ Magtrol SA (Switzerland): 41 (0)26 407 3000 •
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