Dynamometers, also known as dynomometers, dynometers, dynos and, within context, motor testers, are devices that measure force, horsepower, maximum rotary speed or maximum power absorption. Most often, they test and measure the forces produced by an engine. One of the earliest dynamometers, the de Prony brake, was invented in 1821 by Gaspard de Prony. Since that time, in stride with advancements in machining processes, design, material availability and technology, dynamometers have become far more complex. Today, they are available in a variety of shapes and sizes, designed to meet usage and placement requirements. Common applications for dynamometers include: RPM and torque measurement of chain or belt drives, fluid power systems, diesel or gas systems, gearboxes, turbines and other engines used in aircraft, aerospace, marine, automotive and industrial processes.

Dynamometers use a variety of devices to take measurements. For example, many dynamometers use small instruments made only of a transducer, strain gauge and display screen. These devices turn torque force into an electrical signal that they can amplify, convert and display as a measurement. Other dynos use motor testers, which work by using voltage and current probes bound to motor input wires to connect the system to internal voltmeters, ammeters and ohmmeters. Motor testers may be used to determine direction, torque, voltage, power, current, cut-out speed and efficiency. Still others use a non-contact speed sensor that can measure motor shaft speed and thereby ascertain its number of rotations per minute. Read More…

Leading Manufacturers

SAKOR Technologies

Okemos, MI | 517-332-7256

Taylor Dynamometer, Inc.

Milwaukee, WI | 414-755-0040

Go Power Systems

Novi, MI | 248-579-4295

PCE Americas, Inc.

Jupiter, FL | 561-320-9162

Froude, Inc.

Novi, MI | 248-579-4295

Tractel Group

Norwood, MA | 800-421-0246

There are two main types of dynamometers, which are both used frequently in the auto industry and in industrial and manufacturing processes. These are chassis dynamometers and engine dynamometers:

Chassis dynos measure automobile wheel rotation with computer software to determine engine torque. They are a type of torque tester, which is a stationary roller upon which vehicle wheels are placed and their rotation measured. Subsets of the chassis dyno include inertia dynos, which are particularly useful for continuous runs, and hydraulic dynos, which measure engine power with a cell filled with liquid to increase its load.

Engine dynos take measurements straight from the engine, with less computer intervention. They use some analogue gauges and dials, though their final measurement is calculated by a computer. They produce highly accurate, repeatable results. Because they require that an engine be removed from a vehicle before testing, engine dynos are quite popular with engine rebuilders, auto manufacturers and producers of race cars and other high performance vehicles. Their subsets include brake dynos, eddy current dynos, PTO dynos and hydraulic dynos. Brake dynos take measurements by observing engine response to application of variable loads as braking force attempts to slow it down. Eddy current dynos, another type of brake dyno, create a repelling or dragging force between a conductor and a changing magnetic field through the generation of a circulating electron flow.
Dynamometers continue to become more advanced and more automated all the time, and as this trend continues, the degree of human error decreases while measurement speed and accuracy increase. We can expect dynamometers to improve safety, efficiency and performance of engines for many years to come.

Dynamometer Informational Video