05-09-2014, 03:10 PM
“ROPE BRAKE DYNAMOMETER
ROPE BRAKE.pdf (Size: 1.31 MB / Downloads: 35)
ABSTRACT
An absorption dynamometer consisting of a rope encircling a brake drum or flywheel,
one end of the rope being loaded by weights and the other supported by a spring balance. The
effective torque absorbed is obtained by multiplying the drum radius by the difference of the
tensions.
A dynamometer or "dyno" for short, is a device for measuring force, moment of force
(torque), or power. For example, the power produced by an engine, motor or other rotating prime
mover can be calculated by simultaneously measuring torque and rotational speed (RPM).
A dynamometer can also be used to determine the torque and power required to operate a
driven machine such as a pump. In that case, a motoring or driving dynamometer is used. A
dynamometer that is designed to be driven is called an absorption or passive dynamometer. A
dynamometer that can either drive or absorb is called a universal or active dynamometer.
In addition to being used to determine the torque or power characteristics of a machine
under test (MUT), dynamometers are employed in a number of other roles. In standard emissions
testing cycles such as those defined by the United States Environmental Protection Agency (US
EPA), dynamometers are used to provide simulated road loading of either the engine (using an
engine dynamometer) or full powertrain (using a chassis dynamometer). In fact, beyond simple
power and torque measurements, dynamometers can be used as part of a testbed for a variety of
engine development activities, such as the calibration of engine management controllers, detailed
investigations into combustion behavior, and tribology.
In the medical terminology, hand-held dynamometers are used for routine screening of
grip and hand strength, and the initial and ongoing evaluation of patients with hand trauma or
dysfunction. They are also used to measure grip strength in patients where compromise of the
cervical nerve roots or peripheral nerves is suspected.
INTRODUCTION
1.1 Definition of Dynamometer:
Dynamometer a device with a rotating shaft that is coupled to the shaft of a machine under
test to measure the output torque or the required driving torque of the machine. The torque
measured by the dynamometer is multiplied by the shaft angular velocity, measured by a
tachometer, to compute the horsepower of the machine under test. Dynamometers are used to
determine the torque and horsepower characteristics of electric motors, generators, internal
combustion engines, gas turbines, and pumps.
LITERATURE REVIEW
1. Guan and Huang (2003) proposed a method to measure disc brake squeal propensity. In the
past via the complex eigen value analysis, positive real parts always indicate the level of
instability. Instead of using this generic parameter to show degrees of instability, they
attempted to analyze the squeal problem from the viewpoint of energy. The total feed-in
energy was used to indicate the squeal tendency of the brake system, which was derived
using the magnitude and phase of the modal shape coefficient vector. They concluded the
proposed method would be able to predict disc brake tendency as similar as the positive real
parts of t he complex eigen value analysis. Furthermore, the method allows disclosing the
influence of structure design parameter on the squeal propensity and also helps analyzing
the effectiveness of various modifications to reduce/eliminate squeal.
CONCLUSION
A brake is an appliance used to apply frictional resistance to a moving body to stop or
retard it by absorbing its kinetic energy. In general, in all types of motion, there is always some
amount of resistance which retards the motion and is sufficient to bring the body to rest.
However, the time taken and the distance covered in this process is usually too large. By
providing brakes, the external resistance is considerably increased and the period retardation
shortened.
A dynamometer is a brake incorporating a device to measure the frictional resistance
applied. This is used to determine the power developed by the machine, while maintaining its
speed at the rated value.
The functional difference between a clutch and a brake is that a clutch connects two
moving members of a machine whereas a brake connects a moving member to a stationary
member.The determination of power delivered to rotating machinery simultaneous measurement
of torque and shaft speed. Machines used for torque measurement under test – bed condition are
called dynamometer. The type of dynamometer to be used depends on the nature of machine to
be tested.
Absorption dynamometers working principle is that the power measured is converted into
heat by friction or by other means. The power absorbed is lost as heat and is dissipated to the
surrounding where it have no use.
These are used for measurement of power of generator, electric motor, turbines and
engines. Dynamometers are capable only of power absorption include various forms of
mechanical brakes working on dry friction, fluid friction and eddy current brake.