A Conversation with your Dyno Rep – Mark Wellman

What regions of the world do you represent?

I cover a fairly broad spectrum of the world including Central and South America as well as Europe, Russia, and China.

What kind of equipment is typically required in these parts of the world?

In my particular market, selling chassis dynos is a real challenge. I don’t recall having sold one at all. The systems that I’ve primarily been selling have been engine dynamometers, transmission testing equipment and some hydraulic pump and motor testing.

What are some of the Power Test products best suited for these testing challenges?

One of our strengths is our wide range of testing capabilities with equipment able to test engines from 50 to 10,000 horsepower. I actually recently sold a dyno capable of testing 12-or-13,000 so we’re seeing some fairly significant sized engines in these parts of the world.

We’re also still serving a number of large global customers with a transmission and hydraulic test equipment. We work with some of the most recognizable names in transmission testing who have a huge global reach. Wherever you see their products, you can be sure that there is Power Test equipment there as well.

What’s one of the more unique problems you’ve helped your customers solve in recent years?

Most of the solutions I provide to my customers are unique to their situation, but I particularly like solving problems when they need to test engines of a fairly large horsepower range. We are able to offer them what we call a tandem or dual dynamometer system, where we take two dynamometers and couple them together.  This allows them to test large and small engines on the same system.

Is that a custom solution they knew they needed or did your consultation bring that to their attention?

I brought it to their attention because the biggest part of our customer qualifying process is to ask them what range of engines they need to test. We ask for the make, model, horsepower range, and how they plan on testing it. Based on that we come up with the testing solution that offers the best value for their circumstances.

We also take into consideration the volume of engines they’re going to test. There’s a big difference between a facility that does a few tests a week and a facility that is running their dyno non-stop.

What’s the benefit of having a preliminary conversation with you, Mark Wellman, if you’re thinking about buying a dyno?

A lot of people go to the Power Test website and see a product that they think they need, and then they don’t think they need any more information until they’re ready to buy sometimes down the road. The reason they should be talking to me today is so that they can get a better understanding of what their needs actually are from a testing standpoint. Often what I find is that they have a perception of what they want, but once we discuss their equipment and operating environment we may come up with a completely different solution that makes more sense for them in the long-term.

Many times customers don’t see the full scale of the project. They may need to incorporate water cooling systems, exhaust and ventilation, additional power, or more. It’s the big picture solution that we can provide them with instead of just the saying, “We need a 500 horse power dynamometer.” They should know they’re only asking for a small portion of a larger project. After consulting with them, I provide a vision of the future are better equipped to budget and plan when they’re ready to invest.

You’ve been all around the world visiting customers and consulting about dyno testing. What do you get out of visiting customers and use different locations all around the world?

I enjoy great food and I enjoy the many different cultures I’ve gotten to experience.  I also enjoy the challenges of different industries, meeting different people and finding out what’s impacting them and their businesses…

It’s been a really interesting thing to see the different cultures and how their political, economic and business systems work. It’s very eye-opening to see the difference there are between our American culture and others. The opportunity to move around, make new friends, make new business associates, and  be welcomed by all of these countries is quite humbling. I consider myself blessed that way.

Why choose Power Test for your testing needs?

It’s been my experience working with customers and customers who have a competitor’s products, that we do a better job of following through the entire job. From concept of equipment, to upgrading existing systems, to finding alternative solutions, Power Test listens to the end user and truly understands what their wants and their needs are.

I really feel that we provide the greatest value in terms of both products and services. If you define value as a function of quality, price, and service we really do provide a pretty darn good value.

How to Select the Proper Performance Engine Dyno

Water Brake Absorbers

Water brake dynamometers use a hydraulic brake that converts the energy produced by the engine into heat transferred to the water flowing through the dynamometer. There is a stationary side (stator) and a spinning side (rotor) each with cup shaped pockets that transfer water from one side to the other. An automatic control valve bolted to the dynamometer controls the amount of water in the dynamometer based on the test requirements to produce the required load against the engine.

The major advantage of water brake absorbers is that they offer a wide dynamic range meaning one dynamometer can test a wide range of engine speeds and engine torques – the SF-902S dynamometer for example is rated for 15,000 rpm and up to 1,250 lb.ft of torque, however it can also easily test small single cylinder engines that make less than 40 lb.ft. of torque. Water brake dynamometers are also the most economical type of absorber for dynamic testing making them great for a wide range of applications from testing internal combustion engines to electric motors.

Eddy Current (EC) Absorbers

Eddy current dynamometers use an electro-magnetic brake to load an engine. A rotor spins inside a magnetic field created by energizing a stationary coil. The spinning section creates resistance to the magnetic field thus applying load to the engine. This process turns energy from the engine into heat in the rotor which is dissipated by cooling water flowing through the absorber.

The major advantage of water cooled eddy current engine dynos is their precise and rapid load control. Varying the energy supplied to the coil can adjust the load from zero to 100% in a few milliseconds and the adjustment can also be very precise. The drawback to eddy current dynamometers is they are typically 40-60% more expensive than a water brake dynamometer and their dynamic range is narrower as well. This means eddy current dynamometers are typically selected for more specialized testing.

Alternating Current (AC) Absorbers

Alternating current (AC) dynamometers use an electric motor to load an engine. When configured with a regenerative drive the energy the motor absorbs can be converted into electrical energy and returned to the power grid, reducing the cost of testing over time. AC dynamometers offer both excellent steady state and transient control. An additional benefit of AC dynamometers is, in addition to loading an engine, they can also motor an engine to simulate the inertia of a vehicle motoring the engine down a hill or performing tightly controlled transient simulations like those required in a government mandated emissions drive cycles.

Selecting the Type of Absorber

With an understanding of how each type of dynamometer creates load and some of their advantages for different types of testing we can discuss the remaining factors we need to understand to select the proper absorber.

RPM and Torque – It is always helpful to have a torque curve of the engines you want to test – comparing engine torque to dynamometer torque across the speed range allows us to quickly determine the available absorbers for a project. Sometimes the complete torque curve isn’t available – at a minimum we need to know peak torque and the RPM it occurs at as well as the speed range the absorber will need to accommodate. We recommend a 15 to 20% safety margin (depending on the type of absorber) between the dynamometers torque curve and the engines torque curve to allow the dynamometers control system room to maintain control of the engine and for instances where some engines inevitably make more power than expected.

Control Tolerances – Modern electronics have advanced the control tolerances available to water brake dynamometers a long way in recent years. SuperFlow’s dual valve control system found on the SF-Powermark dyno can produce steady state control of +/- 10-20 RPM and it also allows us flexibility to use different control strategies to choose the best one for a given application. Both eddy current and AC dynamometers will have much tighter control in both steady state and transient testing than a water brake dynamometer – here we could expect +/- 2 RPM or better depending on the prime mover.

Test Requirements – All three types of absorbers can perform steady state, step, sweep and transient test profiles. SuperFlow’s WinDyn Data Acquisition and Control System allows users to select the desired profile, input parameters for starting and ending points and ramp or step times and then execute the test. Additionally, track lap data, emissions drive cycles and other transient profiles can be input into the software and run on the dynamometer. Again, only the AC dynamometers are capable of motoring an engine for inertia simulation so any requirement for a drive cycle of other emissions test profile would require an AC system.

Contact Us for System Prices

Combining the overall application requirements for speed, torque, control, and test requirements leads us to the correct power absorber and dynamometer system. Our sales engineers are trained to listen to the application, ask questions when needed and help you select the proper equipment for an economical solution for your project. If you have an engine testing need you’d like to inquire about call us at (262) 252-4301 or contact us online.