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Traction Terminology Traction.: Net Traction Ratio (NTR)

This document defines key terminology related to traction in tractors. It explains that traction is the process by which a tractor develops tractive force to overcome resistance and produce motion. Net traction ratio refers to the pull or weight ratio of a vehicle and considers factors like ballast transfer. Tractive force is the pulling force developed by the traction device from the power source. Gross traction ratio considers just the axle input without losses, while motion resistance includes forces that resist motion like rolling resistance from soil deformations. Other terms defined include sinkage, slip, and traction efficiency which is the efficiency of converting axle power to output power. Testing procedures generally follow relevant standards and involve checking specifications, developing test facilities, conducting tests, analyzing data

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Birjesh Yaduvanshi
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550 views2 pages

Traction Terminology Traction.: Net Traction Ratio (NTR)

This document defines key terminology related to traction in tractors. It explains that traction is the process by which a tractor develops tractive force to overcome resistance and produce motion. Net traction ratio refers to the pull or weight ratio of a vehicle and considers factors like ballast transfer. Tractive force is the pulling force developed by the traction device from the power source. Gross traction ratio considers just the axle input without losses, while motion resistance includes forces that resist motion like rolling resistance from soil deformations. Other terms defined include sinkage, slip, and traction efficiency which is the efficiency of converting axle power to output power. Testing procedures generally follow relevant standards and involve checking specifications, developing test facilities, conducting tests, analyzing data

Uploaded by

Birjesh Yaduvanshi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Traction Terminology

Traction.

The process by which a tractor develops tractive force and overcomes motion
resistance to produce desired motion.

Net Traction Ratio (NTR)

The net traction ratio is sometimes referred to as pull/weight, P/W, dynamic traction ratio, or coefficient
of traction. Most of these terms actually refer to a complete vehicle rather than to a simple traction device.
The dynamic reaction force or dynamic weight (Wd) includes the effects of ballast and any weight transfer
that may occur in the testing process.

Tractive force

 The force developed on the tractor interface by the traction device as a result of
applied torque from the power source.

Gross Traction Ratio (GTR)


Gross traction (GT) is sometimes referred to as rim pull, design drawbar pull, or
theoretical pull. It is the axle torque input converted to a pull force. It is the pull you
would develop if there were no motion resistance loss.

Motion resistance

Any force imposing resistance against desired motion.

Rolling resistance or Motion resistance ration (MRR)

Motion resistance that arises from deformations in the soil  and the traction device

Sinkage

The depth to which the traction device penetrate into the soil measurednormal to the
original, undisturbed surface.

Slip

It is an indication of how the speed of the traction device differs from the forward
speed of the tractor. It can be  defined as as the percentage travel reduction and given
as
S = [ 1 – Va/Vt] 100

Traction efficiency

The efficiency of the tractive device is  converting the axle input power into output
power, the term tractive efficiency (TE) has been defined as

TE = Output power/ Input power x100

Basically tractive efficiency is  converting the axle torque  into net traction .

Procedure of testing
BIS. has published standards on machine/components for the machines used in the
country. Mostly testing of the particular machine is undertaken as per relevant clauses
of the code. In case, the standard has not been published for the machine, code and
procedure is developed by the testing center and same used for testing purpose. These
test procedures help in formulation of test codes by BIS. The complete testing of a
machine involves:

i. Checking of specifications

ii. Development of test facilities and instrumentation

iii. Conduct actual tests

iv. Analysis of the data

v. Presentation of data and report writing

vi. Product certification marks scheme

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