torque trans (1)

8/2/2019 Torque Trans (1)

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A Presentationon

Torque Transducers

By1. Vishal Dwivedi2. Sounak

Mojumder


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twisting or turning force about an axis, that canbe applied in a clockwise or counter-clockwisedirection.

Torque is given as :

T= F.D

where, T= torque, F=force,

D =perpendicular distance from

What is

Torque?


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Applications for torque sensors include determining the power of an engine,

motor, turbine, or other rotating

device stress and deflection analysis

Determining the performance

characteristics of machinesMeasurement Analysis:Dynamic measurement of torque transmitted by a

rotating shaft is

based upon the angular displacement or twist in

Why measure Torque?


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Rotating TorqueTransducers

If a shaft is loaded under torsion, it twists to anangle, proportional to the torque. This angle canbe measured with an angle measuring system


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Bonded strain gauge technology

Four strain gauges are bonded

Use of Wheatstone bridge configuration

Temperature compensation components included within the

bridge circuitry.

an excitation voltage is applied to the bridge

an electrical output linearly proportionate to that torque.

Strain Gauge TorqueTransducers


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Strain Gauge Torque TransducersContd

The gauges should be so mounted that they give maximumsensitivity to the strains produced by torsion.

for a shaft subjected to pure torsion, the gaugeswill be strained in the directions of their majoraxis if they are mounted at 450 to the axis of the

shaft.


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Slip Rings are the

conducting rings

attached to the shaft,

but insulated from it.

Each slip ring is

connected to each of

the bridge terminals.

Rubbing contact is

made between the



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ADVANTAGES:

1. It is fully temperature compensated.

2. It provides automatic compensationfor bending and axial loads.

3. It gives the maximum sensitivity for agiven torque.

DISADVANTAGE:



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Inductive TorqueTransducer

Principle based on Change of Self Inductance:

Self inductance of a coil L= N2 / S,

Where, N = no. of turns ;

S = reluctance of the magneticcircuit.

S = l/ A

Therefore, L = {N2 A / l} = N2 G.

Inductive transducers are mainly used formeasurement of displacement

change ofselfinductance

change ofmutualinductance

productionof eddycurrents

Working

Principle


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Inductive Torque TransducerContd

Flange A carries a coil and

flange B, an iron core.

This core moves in and out

of the coil

Inductance of the coil is

altered on account of

relative displacement.

The coil is used as an arm

of an a.c. bridge. The

output of the a.c. bridge

de ends u on the


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MagnetostrictiveTransducers

The permeability

increases under tensilestress and decreases undercompressive stress.

The wiedemann magnetostriction effect

for the measurement of torquecauses changes in the permeability ofthe materials subjected to tensile orcompressive stresses.

Working Principle:

Two A.C. energizedprimary coils wound on

iron cores, arepositioned close to theshaft so that their fluxpath through the

material of the shaftcoincide with the


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Magnetostrictive TransducersContd

When there is noloading on the shaft,

the permeability ofthe shaft is uniformand equal butopposite voltages are

induced in thesecondary coils S1and S2.

The bridge is initiallybalanced. But whenthe torque is applied

the bridge becomesunbalanced on

account of increase in


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Proximity TorqueTransducers

Construction and Working:

It consist of two identical

toothed-wheels fixed on a

shaft.

Two proximity sensors

(magnetic pickups)

are placed one at each wheel.

When the shaft rotates due to

the applied torque, the tooth of

The rotating shaft torque is determined bymeasuring the angular displacement between the

two sections of a rotating shaft.


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Modern Rotating TorqueTransducers


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Applications:

1. Automotive & Motorsport

2. Aircraft Component Testing & Development

3. Engine Test Stands

4. Marine

5. Production Process Monitoring

6. Pump Development

7. Steel Manufacturing

8. Torque & Power Measurement on Drive

Shafts

9. Tor ue Wrench & Tool Testin Calibration


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torque trans (1)

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