Motor Test Equipment

Hysteresis Dynamometers (HD Series)

SpecificationsOptionsSystem Options
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Dynamometer Features  
  • 16 Standard Models with Maximum Torque from 2.5 oz·in to 500 lb·in (18 mN·m to 56.5 N·m)
  • Hysteresis Braking System: Provides precise torque loading independent of shaft speed
  • Motor Testing from No Load to Locked Rotor
  • Accuracy: ±0.25% to ± 0.5% (Full Scale)
  • Air Flow Sensor: For protection against overheating and operator error
  • Standard Torque Units: English, Metric and SI
  • Base Plate: Available in long or short versions
  • Custom Dynamometers: for special torque and speed requirements
  • Easy Calibration
Hysteresis Dynamometers

Model HD-500 Hysteresis Dynamometer

The Hysteresis Braking System

All Magtrol Hysteresis Dynamometers absorb power with a unique Hysteresis Braking System which provides frictionless torque loading independent of shaft speed. The Hysteresis Brake provides torque by the use of two basic components - a reticulated pole structure and a specialty steel rotor/shaft assembly - fitted together but not in physical contact. Until the pole structure is energized, the drag cup can spin freely on its shaft bearings. When a magnetizing force from the field coil is applied to the pole structure, the air gap becomes a flux field and the rotor is magnetically restrained, providing a braking action between the pole structure and rotor.
Hysteresis Brake cross section

Other Types of Hysteresis Dynamometers
Micro Dyne
Magtrol's new Micro Dyne is the FIRST and ONLY system designed specifically for testing miniature/micro, low-torque motors.

Engine Dynamometer
Used for testing internal combustion engines up to 10 horsepower (7.5 kW).

Dial Weight Dynamometer
Simple to use, reliable, and lower cost dynamometers for manual motor testing.

Special Dynamometer Designs and Modifications

Low Speed
For low speed motors, such as gear motors with maximum speeds of less than 200 rpm, Magtrol offers additional encoder options that allow for increased resolution of the speed signal. Please refer to the data sheet for ordering information.
High Speed
For certain models, Magtrol can provide a dynamometer which can operate at higher than rated speeds.
Magtrol can provide customized base plates, riser blocks and shaft modifications.
Magtrol can provide a 0-5 VDC analog output for the torque signal and a TTL speed signal from the dynamometer.

HD Tandem Dynamometer
Magtrol offers Hysteresis Dynamometers mounted in tandem. In tandem, motors of different size can be tested simultaneously using only one bench. This system also allows different brake - torque transducer configurations according to motor size.
HD Tandem Dynamometer HB 715 + TM 307 mounted in tandem with HB 815 + TM 310

Dynamometer Options
Torque Units
  • 5 Volt Output
  • English (U.S.)
  • Metric
  • SI
Power Operation
  • 120 VAC (standard)
  • 240 VAC (option)
Base Plate
  • Long (standard)
  • Short
  • Long with T-Slots (available on HD-800 series only)
Speed Encoder
  • 60 bit (standard)
  • 60 and 600 bit
  • 60 and 6000 bit
*contact sales regarding speed encoders for HD-100 through HD-500 series dynamometers
**Contact Sales for special designs, modifications, and options.
Ordering Information
Ordering Info
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Magtrol, Inc (USA): 716-668-5555 • ~ Magtrol SA (Switzerland): 41 (0)26 407 3000 • ~ Magtrol India: 91 (0)80 6561 395 7·
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