What is a Dynamometer?
A Dynamometer is a normal device used for measuring torque, power and force. For instance, the Dynamometer can measure the rotational speed, i.e., number of rotations per minute and torque simultaneously by the power produce by a motor or any type of rotating device. A Dynamometer can be of two types. The first one is Active type Dynamometer and the second type is Passive type Dynamometer.
Active type of Dynamometer is a device used to drive or absorb and the Passive type Dynamometer is a device to be driven.
These are the most common dynamometers used in the modern days. Almost all the eddy current
type absorbers are air cooled but only some eddy current type absorbers use external water cooling
systems. It uses conductive core powered by electricity and has a disc moving across a magnetic
field. The mostly used materials are iron and copper but aluminum and other conductive materials
may also be used.
Power Dynamometer is also very similar to the working of Eddy Current Type Absorber but the only
difference is the placing of fine magnetic powder between the rotor and the magnetic coil. These are
usually limited to low rpm. The powder is placed in between them and so the name powder
dynamometer is assigned to this dynamometer. These work only at low rpm as there are many heat
Hysteresis Dynamometers consists of a steel rotor which is moved through the flux lines those
generated by magnetic pole pieces. This disc type design allows the production of complete torque
at zero speed and also at full speed. Hysteresis Dynamometers are the most efficient technologies
especially in small type dynamometers.
These Electric motor / generator dynamometers are a special type of adjustable speed
dynamometers. These types of dynamometers can be run both by alternating current or direct
current. Any AC motor or DC motor can be operated as a generator or as the motor that drives the
unit. Universal dynamometers has the ability to not only absorb the power from the engine but
also to drive the engine which is especially used for measuring pumping losses, friction and many