The goal of utilizing a dynamometer would be to test the burden convenience of a train locomotive just before putting it back in service. It allows for the break-in of a new or newly rebuilt engine in the controllable environment. Engine manufacturers, rebuilders and many fleets have proven this type of break-in procedure through years of experience. Properly run-in engines go longer, run better and cost less to keep up. This short article highlights the operation of water brake engine dynamometer.
An electric train engine with out a load can only produce speed. Maintaining a given rate of revolutions for each minute (RPM) takes a really small amount of engine horsepower. The dyno is really a means by that any controlled load may be added and monitored. With a water brake dynamometer, the horsepower with the prime mover is changed into heat with the dynamometer water. The stators and rotors successfully accomplish that change in energy. Both the stators and rotors have pockets built within them. As water is brought into the engine dyno or chassis dyno by passages in the stator, it is discharged into the dyno near the center of rotation of the rotor assembly. This water entering the dyno will flow into the pockets of the rotor. The water will be accelerated through the rotation of the rotor assembly, which is attached to the output shaft with the engine. Since it accelerates (or accelerates), water tends to fly out as a result of centrifugal force. And as the water flies out, it ends up in pockets within the stator plates. The water during these similar pockets
in the stator plates has a tendency to come to an end and is yet again met by the rotating rotor assembly. The water is increased (or accelerated) again, along with the constant acceleration and deceleration of the water, power is required which can be changed into frictional heating with the water. The thermal conversion of engine power to frictional heating from the water is supported by pure laws of physics.
Horsepower could be defined in terms of heat. Heat loads are measured in terms of "BTUs" or British Thermal Units. A BTU of warmth will be the amount of heat that it would take to enhance the temperature of one pound of pure water by one degree Fahrenheit. When confronted with water brake dynamometers, the heat loads with regards to BTUs are essential.
Because we are raising the temperature of just one pound water by one degree Fahrenheit, we'll need to know other definitions. You can find 62.4 pounds of pure water inside a cubic foot. There are 231 cubic inches in a single gallon of pure water. Therefore, one gallon of pure water would weigh 8-⅓ pounds. One horsepower is equivalent to 2,545 BTUs per hour or about 45.5 BTUs each minute. With this particular information, we are able to now determine the quantity of water that is required to absorb certain amount of horsepower. The quantity of water inside the dyno at any instant determines the quantity of horsepower that it could absorb. The harder water which is inside the dynamometer, the more the dyno can absorb. You can't put more water into the dyno compared to amount for the degree of horsepower
which you plan to test.
The dynamometer doesn't hold water. It is just an instrument for converting the horsepower into heat with the water. For this reason, you will need a given flow from the dyno at a given horsepower rating. The quantity of flow varies because there are many horsepower to be absorbed and it is directly proportional. The better the level of load required, the greater the amount of water will have to be supplied.
The amount of water supplied for the dynamometer is controlled externally towards the dynamometer. This can be done either with a set of secondly
manual shut off valves mounted in the water supply line, through the electric remote load control valve or from the servo-operated inlet manifold option. If the manual or electric valves are used, they both accomplish exactly the same task. The broader the valve is opened, the more water it enables circulation for the dynamometer. This flow towards the dyno is directly proportional towards the quantity of horsepower being absorbed.
An exhaust or outlet valve is also attached to the dynamometer. The objective
of this valve is to conserve water while allowing the dynamometer to operate
on various temperatures of inlet water. Once we are converting horsepower into heat from the water, the partnership from the inlet and outlet water temperatures becomes an important consideration. The exhaust valve is a controlled orifice. The farther it's opened, the larger the water consumption will probably be.
- 2014/02/21(金) 04:43:48|
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