AC (Alternating Current) Absorbers deliver the ultimate in electronic load control. Besides offering load-control response times measured in microseconds and low inertia, they are capable of providing full-torque loading down to zero RPM (allowing stall-testing air or electric motors). Moderate power applications are configured to dissipate their energy into larger external resistive load banks, while for very low power testing, heat dissipation can sometimes be handled by the drive’s internal braking resistors. For applications, in the 200 Hp to 1,250+ Hp range, a regeneration system sends power back into the utility’s grid (for a credit against the user’s electric bill).
Motoring Mode is optionally configurable for any of our AC dyno applications. Only AC absorbers can do double-duty to “motor” your test engine. In addition to its providing a convenient way to start up the engine, motoring allows testing its internal frictional cranking loads on engine dynamometers or simulate down-hill coasting for road-load dynamometer simulations.
3" to 30" Diameter Rotors for loads from under ¼ to over 3,000 foot-pounds. Higher capacities are available from tandem absorbers or via our overdrive systems. Installation options include compact integral PTO drive or trunion mounting – with direct or belt driven shaft drive.
12-volt DC, 120-volt or 2440-volt AC (input) power supply/controls are available to provide 12, 96 or 192-volt DC PWM (pulse width modulated) output – which is suitable for many DYNOmite or third party absorber models. Loading when using these controls is adjustable – either manually (using either its panel knob or the built-in 0-10 volt analog control input) or automatically via digital PID output leads from the DYNOmite data-acquisition computer. Panel circuit breakers are matched to the customer’s application, protecting the absorber’s windings.
Liquid-Cooled Eddy-Current Absorbers offer load-control response times measured in milliseconds, very-low rotating inertia, and compact high-specific load capacity. Compared to water-brake absorbers, they are especially well suited for applications that require plenty of low RPM torque capacity - as do many industrial-type engines. For applications which do not require motoring or stall-speed (zero RPM) loading, our liquid -cooled eddy current absorbers offer more cost-effective loading than equivalent capacity AC absorber (motor) and drive can. For applications that demand high RPM limits, lower system inertia, and continuous-duty (temperature independence) water-cooled eddy-current absorbers are the ideal solution.
We manufacture these absorbers in both single and multi-rotor configurations, in a number of diameter ranges to cover testing everything from tiny 20,000 RPM two -stokes to 1,200 Hp diesels. Rotors are added to increase power capacity, without limiting peak RPM, while rotor diameter is increased for boosting low-RPM torque capacity. Since we manufacture these units in-house, we machine and balance the rotors for the application, wind custom voltage coils, and assemble the ideal stack-up to get the just the load curve you need. Their modular design also allows for the possibility of upgrading capacity if your test engine's increase in size someday.
Planetary-Driven Absorbers compactly couple the high-power absorption characteristics of water brakes to the high-torque requirements of low-rpm axle-shaft testing. These are some of the earliest high-capacity hub-mounted dynamometers. Our custom built, toroidal-flow units are available in capacities to over 2,000 HP (per axle). Because they are packed in billet-aluminum housings, it is still possible for one man to lift and mount the units.
Load control is done via either a manual control valve or with any of our larger capacity electronic auto-load servos. These systems use the same line of load valves as all of our other large water-brake absorbers.*
Water-Brake Absorbers are the first choice when low cost, ultra-low inertia, high rpm limits, and race engine horsepower capacity are all requirements. These have been the favorite of professional automotive engine builders for decades. Water brakes are similar to centrifugal water pumps. Load is controlled by varying the volume of water recirculating within the brake with adjustable inlet and/or outlet valves and orifices. It converts your engine's power output into "instant hot water."
Power capacity versus size of a water brake is impressive. An 8 pound absorber handles over 65 continuous Hp at 12,000 RPM. By comparison, a 300 pound air-cooled eddy-current absorber (with the same continuous power rating) is only good to 7,000 rpm. It is no wonder that water brakes are virtually the only choice for testing 2,000+ horsepower drag car engines. Modern water brakes (like the one pictured at left) boast low enough weight and inertia that they can be directly mounted on the kart engine's output shaft. Direct mounting eliminates the inertia and parasitic drag of driveshafts, u-joints, pillow block bearing, etc.
Manual or automatic control options allow RPM and load adjustment via either an operator twisting a valve knob or a computer with an electronic PID servo. While manual-valve control is not as quick or precise as the electronic option, it is an inexpensive place to start – and is easy to upgrade and needs or budgets allow. We even offer do-it-yourself plans to help you build everything from the test stand to a whole dynamometer cell.
Custom hybrid configurations can can also be designed using a combination of both an electronic, typically AC, absorber (for fast torque control) and a large water brake (for inexpensively adding very-high test power capacity). Control of the pair is handled via DYNO-MAX “Pro.” While their complexity is typically only justified for some sophisticated high-output applications, hybrids make it possible to cost effectively build lower inertia and faster response dynamometers, (with motoring capabilities) than can be had using any single braking technology alone.
Need repairs on an old absorber? As a manufacturer of dynamometer absorbers and controls, we can often repair otherwise obsolete units. L&S does everything, from modernizing electronic power supplies or water-valve controllers to custom winding replacement coils for “Brand-X” dynamometers.
Call for immediate assistance in developing your own unique testing solution - or e-mail email@example.com for a prompt response. **Approximate; continuous capacities depend on selected absorber and test speed. Air-cooled absorber loads are rotor temperature dependent. Water brake power capacities are RPM dependent and assume a minimum water supply of 1 gpm @ 30 psi for every 20 continuous Hp. Call Land & Sea, Inc. at (603) 226-3966 for the approximate capacity of any specific test configuration.