Torquemeters Limited, founded in 1951, have a

worldwide reputation for torquemeters of very high

accuracyand credibility both for test stand Research

and Development applications and also for

permanent installation on large turbomachines.

The efficiency, reliability and quality of all rotating

machinery, large and small, is of paramount

importance to end users, and to remain competitive

suppliers need to test prototype and production

machines with increasing thoroughness.

The margins for improvement are already so much

reduced that success depends on highly accurate

test stand measurements, particularly torque.

Operators of large turbomachines are also

increasingly interested in their in service

performance and use permanently installed

torquemeters for condition monitoring, maximising

plant output and control purposes.

Their'Torquetronic' phase shift system, originally

licensed from Rolls Royce, is used by many of the

world's leading aero engine and turbomachinery

companies and is available as a 0.1% accuracy

standard model range or custom engineered to suit

specific requirements.

Torquemeters Limited are also the world leaders in

continuous duty torquemeters for the oil, gas and

petrochemical industries, with over 350 units in

service on turbomachines up to 80MW and

20,000rpm with exceptional reliabili~

Applications fall into two categories.

Power Absorption Measurement -of pumps,

fans, compressors, generators, gearboxes, etc using a

torquemeter and any convenient prime mover:

Power Output Measurement -of turbines, I.C

engines, electric and hydraulic motors, etc using a

torquemeter and any convenient load absorption

device.

The mechanical design and interfacing of

torquemeters to the coupled machines can be

critical to their success. and the Company's

reputation is based on their unique capability in high

speed transmission engineering at high powers

speeds up to I 50.000rpm.

Operating from a purpose built factory with

modern production, calibration and design facilities,

the Company are certified to ISO 900 I. Sales,

technical support and after sales service for the

Company's international customer base is handled

by a network of sales offices and agencies covering

20 countries worldwide.

Some practical applications:

Performance measurement -Research and

Development testing of prototype machines to the

highest levels of accurac~ such as aero engine or

industrial compressor development.

Production testing -Pass off testing of production

machines such as helicopter or automotive engines,

pumps, etc.

Acceptance testing -Works or on-site acceptance

of performance guarantees of coupled machines.

Machinery protection -Indication of peak

operating torque to prevent damage to process

machinerr

Process control -Optimisation of process plant

machinery to maximise output, efficiency and product

quality.

Condition monitoring -Continuous indication of

performance deterioration of process machines

guides maintenance and cleaning scheduling.

I

Phase shift principle

This simple form of phase shift torquemeter is well

known. As torque is applied to the rotating shaft, a

change of phase is produced between the signals of

the two pickups. Howeve~ large inaccuracies are

introduced by any relative movements between the

shaft and the pickups. i iI I..

To Phasemeter

Torquetronic system

The 'Torquetronic' system's key feature is the use of

a pair of multipole pickups in the form of internally

toothed rings, which provide compensation for any

relative movement between shaft and stator:

The circumferential pickup / field coils provide a

toroidal flux path such that as the shaft rotates, the

teeth generate sinusoidal signals in stationary coils,

whose phase dispJacement is directly proportionalto shaft twist and hence torque. .

The integrity of the phase measurement electronics can

be conclusively proved by inverting the two signals using

a built in Complement switch. If the sum of the original

and Complement readings add up to exactly 100% the

phase measurement must be correct.

I .I II I

..

Complement ~

switch ~

~

TORQUE

(as % phase displacement)

Rotastat feature

'Torquetronic' test stand models feature a built in

Rotastat system in which the pickup teeth can be

rotated to generate signals with the shaft stationary.

This allows static calibration with lever arms and

weights and zero speed torque measurement.

The calibration constant of the system is simply the

torque to twist the shaft through one tooth pitch which

must clearly correspond to exactly 100% phase

displacement. The stiffness of the high tensile steel shaft

is as stable as Youngs modulus and exceptionally linear:~ ~

To Phasemeter

2

Standard 'ET' models

The ET model range of high

precision transducers covers 1-

75,000Nm, up to 120,000rpm

in 4 frame sizes. Available in

suspended or pedestal versions

and Low, Medium and High Speed

bearing contigurations.The unique

interchangeable shaft facility

typically allows each model to

cover a 40: 1 torque range at full

accuracy.

ET I SOHS -14OONm, JO,OOOrpm

ET9000HS- 75,OOONm, 6,500rpm

Custom designs

For special test rig applications at

high or low speed,Torquemeters

Limited can provide custom

designed solutions, including the

complete transmission. Any rating

considered.

Turbine test rig- 24000kW 13,OOOrpm

3

Continuous Duty

For condition monitoring of large

turbomachines in the oil, gas

petrochemical industries,

Torquetronic is widely regarded as

the most reliable and credible

system available with over 300

installations on virtually every

turbine type from I -80MW.

(Ref Brochure PSL 9.05.65)

Gas pipeline booster 20MW @ 6,500rpm

Tordisc couplings

For exacting test stand applications

Torquemeters Limited offer a range

of standard or custom designed

ultra lightweight low moment

TORDISC diaphragm couplings.

Torques up to 30,OOONm, speeds

up to 80,OOOrpm.

Electronics

All 'Torquetronic' transducers

use common electronics, the

"613" Readout Unit or the

'700" Signal Processor Unit,

available with a wide range of

digital and analog interfaces.

(Ref Brochures PSL 9.05.55 /56)

.00.0 I % RD.

0.02% RD.

0.05% RD.

0.05%

0.05%

Irpm

.9 rSpecifications -ET models

Resolution:Linearity + Hysteresis

Zero Repeatability :t

Temperature Compensation :t

Static Calibration :t

Speed :t

i-i\

The combination of the errors above in relation

to the full scale Phase Displacement (PD.),

typically 75% gives:

w .8

::>--'

~O .7

~::>';:i .6

wL0\! .51/1«>-U .4

~::>UU .3

«

.2

Overall accuracy: @ 95% Confidence level

JTE

RJPEATABltl~ ~ ~

R~PEATABI~ITY I ~

0.13% F.S.D.

0.10% F.S.D.

Absolute

Repeatability

:!:

:!:

Operating temperature -40 + 100°C0

20 30 40 50 60 70

% PHASE DISPlACEMENT

80 90 1000 10

5

Fig2

10 20 30 40 50 60 70 80 90 100OBSERVED READING ~P.D)

The "Torquetronic" principle was

conceived to provide the highest level

of torque measurement accuracy and

credibility for the exacting task of

aero engine development. However;

the practical accuracy of any

Torquemeter is no more than can be

proved to the users own satisfaction.

Unlike most measuring instruments

the transmission Torquemeter cannot

be calibrated against any standard.

The "Torquetronic" system was

designed from the outset so that its

integrity'can be readily proved by the

following indirect tests.

.Static calibration -

Application of torque without

rotation

.Dynamic calibration -

Application of rotation without

torque

Static calibration

The torsional stiffness of the shaft or the

calibration constant is simply determined with

lever arms, normally provided, and weights. The

calibration is thereafter as stable as Youngs

modulus and is strictly linear:Very large shafts are

usually supplied works calibrated on our 140kNm rig. Fig.1 shows the results of a typical calibration model, to

a linearity of 0.0 I %RMS. The minor effect of shaft temperature on stiffness is precisely known and may be

corrected for; using a shaft thermocouple.

Dynamic calibration

The Torquemeter is run with the

driven machine uncoupled to establish

the Zero Torque Datum (Z.TD.) Fig.2

shows the results of a typical

calibration.

Any systematic variation with speed is

compensated electronicallfAll transducers undergo no load

testing and calibration up to their

maximum operating speed on the

company's 120,OOOrpm spinning facilitfReadout integrity is proven by a

Reading + Complement check, Fig.3.

6

Standard ET models

L.$.

M.$,

H.$,

$,

Nominal ratings for standard Torquemeters

Special consideration for each application is advisable

Low Speed, Grease Lubricated

Medium Speed. Grease Lubricated

High Speed. Oil Lubricated

Suspended, Low Speed. Grease Lubricated

105 105

~

~ET5000~

1""'::- IU~ET3000

-ET2000

I

,~ET1000

I~ET12°1!;ET1000r ' I

104 10.

1- ETiiiO ~~

"ET600'""::-

~M.S.~ ET250

rET150 ~I~

103 103~ETio~"-

I. ET60 .L

~1- ET25 .

-ET26-

-ET25'

~ ~

~ T15. ET12!

, -

~ ET10 ~

102 102

~i " ~

~~

~ ~H,S~ET6

rETS

10 10

~

E~w::>OQ:

~

E~w:JOIx:

~

'rque Range

0.74 Ibf ft

)g Interchangeable Shafts

INm

specification.que shaft ratings are made to customel

Easi terchangeable ti N full accuracy t inel ler a very wide je range.

7

~

rrf{

Installation

Pedestal type

The transducer is fixed to a

bedplate. The couplings each side

must have two flexible planes.

Preferred choice for high speeds.

Convenient for calibration

Suspended type

The transducer is supported by the

shafts of the associated machines.

The couplings on each side must

have a single flexible plane. Casing

rotation is restrained by a link

Coupling selection

Whilst the 'T orquetronic' transducers are designed to be insensitive to external shaft loading, T orquemeters

Limited's extensive transmission engineering experience is available to assess or recommend coupling selection.

For higher speeds and powers Torquemeters Limited manufacture the TORDISC, an advanced Low Mass

Moment, profiled membrane coupling for speeds up to 80,OOOrpm and torques up to 30,OOONm.

Lubrication

Low and medium speed models are grease lubricated. High speed models are oil lubricated with air packed

seals pressurised from an external fan.Type K bearing thermocouples are standard on Medium Speed and High

Speed models.

Temperature Compensation

For the highest possible accuracy or for use in high ambient conditions, a shaft thermocouple/RTD can be

supplied for automatic modulus compensation (O.O25%/OC)

Torque helix

This is a useful way of defining the sense oftorque.T ransducers can be specified for unidirectional or

bidirectional use.

LEFT HAND HELIX -

Shaft is twisted as a left hand thread

RIGHT HAND HELIX -

Shaft is twisted as a right hand thread

9

GEC MARCONI

GIRDLESTONE

GKN

GLAENZER SPICER

GODIVA

GODWIN

GRASSO

ABB

AEROsPATIALE

AEROTEsT

AGUsTA

ALLIED SIGNAL

ALLISON

ALVis

ARIEL

AUXILEC

PEUGEOT

PHlLIPS

PIAGGIO

PLESSEY

PRATT & WHITNEY

HAYWARD TYLER

HELIKOPTER SERVICES

HOBOURN

HONDA

HOWDEN

HPI

REM

RENAULT

RICARDO

ROLLS ROYCE

ROVER

RWTH

BHEL ,

BMW-RRBUMBW/IP

IAC

IFP

ILMOR

ITP

SAUER SUNDSTRAND

SNECMA

STORK

SULZER

SUNDSTRAND

SVERDRUP

CAMBRIDGE UNIVERSITYCATERPILLARCEAT

CEGELECCEPR SACLAYCOMPAIR

COSWORTHCRANFIELD

KAWASAKI

KSB

TECHNOFAN

THOMASSEN

TOYOTA

TURBOMECA

DEMAG DELAVALDELPHIDFVLR

DOWNLEROY SOMER

LUCAS AEROSPACE

u s NAVYEDFEGT

MAN GHH

MAWDSLEYS

MHI

MTUVOlVO

FIAT

FISCHERFLEMINGFROUDE

WEIRS

WESTLANDS

NAL

NASA

NIJHUIS

NISSAN

NORMALAIR- GARRETT

NOVENCO

NUOVO PIGNONE

GARRETT

GEGEC ALSTHOM YORK

10