A dynamometer measures torque as it applies drag resistance on a motor; it can do so at various speeds and powers. Dynamometer manufacturers produce units compatible with motors, engines, turbines transmissions, fluid systems and other machines for automotive, marine, industrial and general purpose applications.

There are also air dynamometers that test jet engines. Dynamometers often have auxiliary testing capabilities, like exhaust monitoring as well as vibration and temperature measuring. Dynamometers implement a wide range of mechanisms to operate, a few of which appear in the list below:

1. Impeller equipped air dynamometers measure jet or gas turbine power.

2. Both AC and DC motors run dynamometers to measure both torque and power.

3. Eddy current dynamometers measure torque as a machine increases torque in the dynamometer.

4. Friction brake dynamometers operate similarly to car brakes, where a drum attaches to the measured device, and the dynamometer applies pads or shoes to the drum.

5. Hysteresis dynamometers totally avoid touching the measured device by applying magnetic resistance.

6. Hydraulic dynamometers use water flow to measure machine outputs.

Action Steps
The best contacts and resources to help you get it done

Choose from dynamometer suppliers that carry units to fit your application

Determine the approximate parameters of your application; then find a dynamometer that can handle those parameters. Namely, look for maximum power and torque ranges. Also consider the maximum rotary and linear speed if the dynamometer manufacturer lists them.

I recommend: If you are looking for an engine dynamometer for sale, go to Land & Sea. They carry a wide range of chassis and on-board dynamometers for cars, snowmobiles, small watercraft and engines. They also carry conversion systems and their equipment has extensive software and readout features. SuperFlow Technologies Group is another good choice. They have many of the same products, in addition to torque converters and heavy duty transmission equipment.

Find dynamometers for sale that mount appropriately for your application

Various dynamometers mount quite differently, so you'll need to find one that can adapt to your specific application. Dynamometers that have a chassis mount work well with wheeled machines, like cars. Trunnion dynamometers adjust to various angles. For in-line mounting, use a shaft mount dynamometer. There are also pedestal, portable and various specialty dynamometer mounts.

I recommend: Among dynamometer distributors, Mustang Dynamometer has one of the widest ranges of mounting types from chassis dynamometers (fit for everything from cars to semi-trucks) to brake stand dynamometers. They also carry transmission, ATV and many other types of dynamometers. Johnson Scale Co. helps round out the range of dynamometers with models for in-line loads, such as in scales.

Track down quality used dynamometers or a dynamometer for rent

If you are looking to cut down on costs, quality used dynamometers are available. If your need for a dynamometer is only temporary or occasional, renting is another option.

I recommend: DyneSystems, Inc. carries used eddy current, AC and DC dynamometers from brands like Midwest, General Electric and Dynamic. Alternatively, Magtrol, Inc. is one of many companies that rent dynamometers. Their specialty is hysteresis dynamometers for motor testing.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Use a towing dynamometer to test how a trailer will affect a vehicle.