HD Series – Hysteresis Dynamometers

Product Description

Hysteresis Brake Dynamometers (HD Series) are versatile and ideal for testing in the low to medium power range (maximum 14 kW intermittent duty). With a Hysteresis Braking system, the Dynamometers do not require speed to create torque, and therefore can provide a full motor ramp from free-run to locked rotor.

Brake cooling is provided by convection, compressed air or a dedicated blower, depending on the model. All Magtrol Hysteresis Dynamometers have accuracy ratings of ±0.25% full scale, depending on size and system configuration.

Features

• 16 standard models with maximum torque from 2.5 oz·in to 500 lb·in.
• Hysteresis braking system provides precise torque loading independent of shaft speed.
• Motor testing from no load to locked rotor.
• Accuracy: ±0.25% full scale.
• Air flow sensor for protection against overheating and operator error.
• Standard torque units: English, Metric and SI.
• Custom dynamometers for special torque and speed requirements.
• Easy calibration.

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.

Specifications and Drawings

• Model HD-510, HD-515, HD-800 and HD-805 Dynamometers require air cooling provided by user.
• Blower package is included as standard equipment with Model HD-710, HD-715, HD-810, HD-815 and HD-825 Dynamometers.
• All -5N(A) dynamometers are 5 Volt Output.

Contact Magtrol for 6N English, 7N Metric and 8N SI specifications.

Blower Dimensions

Allow approximately 6 in to 8 in, or 152 mm to 203 mm, between rear of dynamometer base plate and blower for connection hardware. Required hardware is supplied with the dynamometer.

Blower Power and Fuses

• Models HD-710, HD-715, HD-810 and ED-715 include the BL-001 blower.
• Models HD-815 and ED-815 include the BL-002 blower.
• Model HD-825 uses two BL-002 blowers for cooling its two brake sets.

Applications

• Motors:
  • Combustion engine, including automotive, motorcycle and chainsaw applications.
  • Hybrid motors.
  • Electric motors.
  • Hydraulic motors for aerospace and machinery applications.
• Pumps, including hydraulic and oil pumps.
• Propellers for aerospace, marine and helicopter applications.
• Automobile industry torque measurement for production and laboratory testing.
• Reduction gears and gearboxes.
• Clutches and overload clutches.
• Motorized valves, drills and pneumatic tools.
• Other machine tools.

System Options

To help you select components for your motor testing system, this table shows which electronics, software and accessories support Magtrol’s different types of dynamometers.

Dynamometer Selection

Magtrol Dynamometers cover a wide range of torque, speed and mechanical power ratings. To select the appropriate size dynamometer for your motor testing needs, determine the maximum torque, maximum speed and power applied to the dynamometer.

Maximum Torque

Consider all torque points that are to be tested, not only rated torque, but also locked rotor and breakdown torque. Selection should initially be based on the maximum torque requirement, subject to determining the maximum power requirements.

Maximum Speed

This rating is the maximum speed at which the dynamometer can be safely run under free run or lightly loaded conditions. It should not be considered the maximum speed at which full braking torque can be applied.

Maximum Power Ratings

These ratings represent the maximum capability of the dynamometer braking system to absorb and dissipate heat generated when applying a braking load. Power absorbed is a function of torque and speed.

The dynamometer’s ability to dissipate heat depends on how long a load is applied. Maximum power ratings are based on continuous operation under load, as well as a maximum of 5 minutes under load.