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Yes, as long you consider the following:
- The outlet water from all Go Power Systems dynamometers is designed to be channeled to a gravity drain with no restriction. In a semi-closed-loop system, a vented drain tank must be situated near the dynamometer outlet(s). You also need a submersible or externally mounted transfer pump to recirculate the water back to the supply source. Failure to correctly plumb your water system can result in hydraulic lock, back pressure, and general instability issues.
- The discharge water from the dynamometer is hot when it exits the dynamometer because the process of absorbing power converts the crankshaft rotation energy into heat. Therefore, an intermediate water cooling device must be installed in the line from the gravity drain tank and back to the supply tank. Your Go Power Systems sales engineer can help you determine the cooling requirements for your application.
An adequate water system is the most important factor to consider for optimal performance, durability, and repeatability of a water brake dynamometer. It is imperative to ensure your system is capable of delivering both the proper pressure and volumetric flow rate to the dynamometer load control valve. Go Power Systems offers Water Delivery System (WDS) packages that are designed and properly sized for each dynamometer model. These systems guarantee that the performance of the dynamometer matches the associated duty curve for the model it is designed to support. A basic water system consists of:
Supply Water Tank: The capacity of your supply water tank is based on:
- The type of testing you plan on conducting, whether holding values at various steady-state test points or performing brief Wide Open Throttle (WOT) power curve determination runs.
- The power range you’ll be operating at.
- The duration of your tests (which dictate how much water you will use).
An over-sized supply tank will help, but if dumping the hot effluent water from the dynamometer directly back into the supply tank, your inlet water temperature will quickly increase as the test continues. This change in inlet temperature causes the density of the inlet water to decrease which changes the dynamometer’s absorption profile. Go Power Systems water brake dynamometers require discharge water to drain unrestricted to a gravity drain point, meaning, the drain must be routed to a drain point lower than the absorber (such as a floor drain).
If discharging to a holding tank, make sure the connection point is below the center line of the dynamometer, but also above the maximum water level of the tank. Refer to the water flow specifications of your specific dynamometer model or consult with your Go Power Systems sales engineer for your specific requirements.
NOTE: To reclaim water for recirculation, a vented drain tank is required to collect the exhausted load water. In a semi-closed-loop system, the dynamometer discharge water cannot be transferred directly back to the supply tank. Remember, you’re using water to absorb the power output of the engine which is converted to heat. Therefore, the dynamometer discharge water must be cooled prior to reuse. An industrial evaporative-type cooling tower is designed specifically for this purpose. Depending upon the application and power absorption requirements, it can be also done in a number of other ways. A more economical means is to have an intermediate cooling tank where the water can settle and cool to ambient temperature or use a series of radiators with electric fans. If your facility has a chiller system, we offer our WDS systems with a plate-and-frame type heat exchanger skid for integration into the cooling circuit. Go Power Systems can provide a water cooling system designed to fit your testing application. Ask your sales engineer for details.
Booster Pump: A centrifugal-type pump with a flat-head profile is commonly used and most reliable for providing adequate pressure and volumetric flow rate to support dynamometer operation. Depending on the model and capacity dynamometer selected, the hp rating for the motor varies. If an engine cooling tower is required, the additional water needed to facilitate this load must be accounted for in sizing the pump. It is always good practice to oversize the water system and its components to allow for future upgrades. We do not recommend using a positive displacement pump because the design of this style pump will continue to build downstream pressure in the event of inadvertently shutting the dynamometer load control valve. If the relief valve fails or is set to an improper pressure, the pump will continue to pressurize the system until the weakest component gives, thereby relieving overpressure.
The distance between the booster pump/pressure relief/regulator outlet and dynamometer load control valve should be minimized. This ensures that the pressure and volume delivered to the dynamometer is not affected by the head-loss associated with the distance traveled through a piping system. If your pump fails to provide the minimum required supply pressure and volume the dynamometer is designed to operate with, you’ll effectively decrease the absorption capacity of the brake unit and therefore the maximum power.
Water Pressure Regulator/Relief Valve: The water delivery pressure requirement varies depending on the model/series of dynamometer selected. The output pressure of a centrifugal pump is fairly steady by design, but the pressure must be regulated to a level consistent with the power absorption profile of your dynamometer. Water brake dynamometers have water pressure and volumetric flow rate specifications that coincide with the unit’s optimal performance characteristic. Water brake dynamometer optimal performance occurs when all conditions are met to achieve linear control throughout the unit’s power absorption range. A water pressure regulator/relief valve, when paired with a sufficient booster pump, ensures the proper water delivery criterion is met. All water requirements noted on our product data sheets denote the pressure and volumetric flow rate required at the inlet to the load control valve to achieve the dynamometer’s optimal performance. The water pressure regulator/relief valve should be mounted at the outlet of the pump in line with the load control valve.
Load Control Valve: The amount of water to and from the dynamometer is controlled by throttling a valve in the inlet and/or outlet to achieve and hold torque values at a specific rpm or control the engine’s output progression. Manually operated globe valves, ball valves, and needle valves are all good for controlling a water brake dynamometer’s varying volumetric flow rate of water. Valves used in automatic load control systems are often teardrop valves, spool valves, or stepper-motor-operated butterfly valves.
CAUTION: GATE VALVES ARE NOT DESIGNED TO THROTTLE WATER. The design of a gate valve is for isolation only. Attempting to control loading of a water brake dynamometer with a gate valve will result in a turbulent, non-linear control profile of the dynamometer. All load control valves should be located as close to the dynamometer as possible without sacrificing personnel safety. For additional information, contact your Go-Power Systems sales engineer for details.
Plumbing: The routing of your plumbing is as crucial as the equipment you purchase to support the dynamometer test cell. It is always important to minimize joints and bends in the supply line to your dynamometer inlet. The supply pump should not be mounted in a position where it has to draw water upward from its supply tank. If an underground tank or the supply tank is located in a different area than the dynamometer, minimize the distance from the supply source to the pump inlet. If the supply tank is located outside of the dynamometer test cell, you may need an additional booster pump to satisfy the inlet pressure and volumetric flow rate requirements of your dynamometer.
If a 90-degree bend must be made, be sure to install at least one foot of straight pipe/hose prior to any system component. This allows the turbulent flow created by the rapid fluid direction change to dissipate while traveling through the bend. Use flexible, non-collapsible hose to make otherwise sharp bends more gradual and limit the pressure drop normally experienced when using threaded or copper plumbing fittings. PVC, CVPC, or PEX can be used and have lower head-loss characteristics than carbon steel pipe. However, temperature must be monitored to ensure the deformation/melting point of the material is not exceeded.
Our portable dynamometers can also be used in driveshaft applications. We manufacture many dynamometer stands to suit practically any test setup. When a chassis dynamometer is not practical or available, the DT-series dynamometers can be fitted with our IFA-D2000 in-frame adapter. This device can be mounted within the driveline of heavy-duty trucks for in-vehicle engine testing. An additional advantage to owning a portable dynamometer is that when your engine testing is completed, the dynamometer can easily be disconnected and stored until it is required again for service. Go Power Systems portable dynamometers are truly the ultimate bolt and go: solution to all of your testing needs.
Each dynamometer series and model has a different absorption characteristic and therefore a different duty curve associated with its capabilities. If you have a small engine or electric motor, our D-100 dynamometer model is probably best suited for you. Most automotive applications, smaller diesel engines, or other higher rpm prime movers will fit into one of the three models in our 57-series dynamometers.
Heavy diesel engines, piston aircraft, and other high torque/low rpm applications will fit the DT dynamometer series. Go Power Systems sales engineers can help you determine which dynamometer best fits your testing requirements.
Dyno Model-Specific FAQs
The D-312/512 can be identified by checking the connection method of the removable hub adapter at the input end. If you purchased the dynamometer and it came with a mounted, splined input shaft adapter, removed the mounting bolts and look at the end of the shaft/input shaft hub assembly. If the main shaft has short male splines and the shaft hub assembly has corresponding female splines and a C-clip retainer, it is a model D-312/512. The D-316/516 is virtually the same as the D-312/512, but has a smooth bore hub adapter keyed onto the main shaft.
All of the above models are single-trunnion units with alloyed aluminum construction and some spare parts may still be available. If you have any questions, your Go Power Systems Sales Representative will be happy to assist you.
A driveshaft can be used for setups that require additional clearance; However, if using this method of testing, Go Power Systems recommends supporting the driveshaft with bearings after alignment. Also, the driveshaft must be torsionally compliant and, for safety purposes, must have a driveshaft guard.
If you are considering purchasing a used dynamometer and don’t have a chance to inspect it before buying, you can check several items after it is in your possession. Try to rotate the shaft/rotor assembly by hand. It should have a reasonable amount of resistance due to the spring pressure of the mechanical seals working against you, but it should rotate somewhat freely.
Next, turn the unit upside down (with the inlet/outlet fittings pointing up) and support it in this position. Grease all bearing fittings, flushing the old grease out until it is expelled from the bearing races. Fill the absorption module with antifreeze or ethylene glycol and let it set for about an hour. If dry, the seals will expand and the internals will have a nice lubricating coating. Try to slowly rotate the shaft/rotator assembly several times in both directions (remember that all Go Power Systems portable dynamometers, with the exception of the DT-3000, are bi-directional units). Repeat this step several times over the course of a day. If the dynamometer still does not free up at this point, it may be in need of an overhaul kit. Contact Go Power Systems for more information.
CAUTION: You must dispose of the antifreeze or ethylene glycol fluid in a manner consistent with your local environmental protection requirements. This includes flushing the dynamometer several times with clean water to remove residual antifreeze. Do not dispose water containing antifreeze or ethylene glycol into a city sewer system or on the ground. This can lead to ground water contamination.
Ask these fundamental questions:
- How many runs has it performed and for how many hours?
- When is the last time this dynamometer was loaded on an engine run?
- Are you the original owner? If not, is the person you obtained it from the original owner?
- Has this dynamometer been overhauled? If yes, what work was done and What was replaced? Was the work performed by Go Power Systems?
- Did the dynamometer have any problems prior to removing it from service? Is it in need of an overhaul?
- Does the dynamometer leak from anywhere?.
The only hydraulic fluid Go Power Systems recommends is Dow Corning 200 silicone fluid. Any other fluid, such as ATF, may contain detergents that chemically attack the diaphragms and cause leaks or premature failure. Load cell diaphragms for very old models are no longer available through Go Power Systems. We can provide a load cell refill kit for recharging the fluid system. For ease with the bleeding procedure, make sure your dynamometer is equipped with bleed screw assemblies at the top of each load cell Canister. If you have an older model and have no way to bleed and recharge the system, Go Power Systems also manufactures a torque line assembly upgrade with the correct fittings for purging air and refilling your hydraulic load cell system.
CAUTION: You must take care when replacing load cell diaphragms. To avoid tears or improper installation, contact Go Power Systems or refer to the Service section of your owner’s manual. If your diaphragms have failed, the most likely cause is age, improper fluid, or improper installation.