Torque Seminar 24.05.2015, Page. 1Hottinger Baldwin Messtechnik GmbHKlaus Weissbrodt The nominal (rated) sensitivity The nominal (rated) sensitivity.

18.04.23, Page. 1 Hottinger Baldwin Messtechnik GmbH Klaus Weissbrodt

Torque Seminar The nominal (rated) sensitivity

The nominal (rated) sensitivity Cnom is given by the span between the output

signal at nominal (rated) torque Mnom and at zero torque related to nominal

(rated) torque Mnom.

Output signal at

zero torque S0

Output signal at

nominal (rated)

torque Sn

Characteristic curve

(increasing torque)

Ideal straight

Actual straight

Sensitivity

tolerance

Nominal (rated) torque Mnom

Act

ual s

igna

l spa

n

Nom

inal

sig

nal s

pan

nom

nnom M

SSC 0


Torque Seminar The nominal (rated) sensitivity


Torque Seminar

15kHz

10kHz

5kHz

+10V

0V

-10V

-Mn+Mn0-Mn

+Mn0

The nominal (rated) sensitivity


Torque Seminar The sensitivity tolerance

The sensitivity tolerance dC is the permissible deviation of the actual output

signal span at nominal (rated) torque Mnom from the nominal output signal

span.


Torque Seminar

The linearity deviation including hysteresis dlh is the maximum deviation of the output

signal value from the reference straight line which is the best-fit straight line through

the starting point. The parameter dlh is specified as a percentage of the nominal

(rated) sensitivity Cnom.

Linearity deviation including hysteresis

Output signal at zero torque S0

Ascending series

(increasing torque)

Descending series

(decreasing torque)

Reference straightOutput signal at

nominal (rated)

torque Sn


Torque Seminar Linearity deviation including hysteresis


Torque Seminar Temperature effects

The temperature effect on the zero signal TK0 is the variation of the unloaded

transducers output signal related to the nominal (rated) sensitivity Cnom,

caused by a 10K change in temperature.O

utpu

t sig

nal

Torque

TK0





Out

put s

igna

l

Torque

TKC

The temperature effect on the sensitivity TKC is the variation of the loaded

transducers output signal related to the actual value of signal span, caused by

a 10K change in temperature.





Both temperature effects appear together.

Out

put s

igna

l

Torque

TK0 + TKC


Torque Seminar The relative standard deviation of the repeatability

S1,100%

S1,50%

S2,100%

S2,50% Sn,50%

Sn,100%

Time

100%

Torque

50%

0

n

i iSnS

1 %50,%50

1

n

i iSnS

1 %100,%100

1

Arithmetic mean of the measuring signal Si

at 50% or 100% of nominal (rated) torque,

n = number of measurements

21 %50%50,

%50%100%50, 1

11

n

i irel SSnSS

21 %100%100,

%50%100%100, 1

11

n

i irel SSnSS


Torque Seminar The relative standard deviation of the repeatability


Torque Seminar Load limits

Nominal (rated) torque

Maximum service torque (see amplifier)

Limit torque

Breaking torque

Torque

Capable to measure,limit values maintained

Capable to measure,limit values not maintained

No permanent variation or damage Permanent variation or damage possible

Mechanical destruction possible

Not capable to measure

0

see data sheet


Torque Seminar Load limits


Torque Seminar

bMbMaF aF

rF

rF

The axial limit force Fa is the maximum permissible longitudinal force.

The lateral limit force Fr is the maximum permissible radial force.

The bending limit moment Mb is the maximum permissible bending moment.

If one of the above parameters is exceeded, the ability of the transducer to

measure may be permanently damaged.

The permissible limits of the above parameters get smaller than the specified

limits, if at least two of these irregular stresses occur simultaneously or if the

nominal (rated) torque is exceeded.

Load limits – parasitic loads


Torque Seminar Load limits – parasitic loads


Torque Seminar Load limits – parasitic loads


Torque Seminar Load limits – permissible oscillation bandwith

Tor

que

Time

+ 5kNm

- 5kNm

Example: torque flange T10FS / 5kNm, oscillation bandwith (peak to peak): 8.000Nm

8kNm

8kNm

The permissible oscillation bandwith is the oscillation amplitude of a

sinusoidally varying torque, with which the transducer can be stressed for at

least 10•106 vibration cycles without causing any significant variations in its

metrological properties.


Torque Seminar Load limits – permissible oscillation bandwith


Torque Seminar Torsional stiffness

The torsional stiffness cT describes the relation between torque and elastic

torsion over the axis of rotation.

D

T

Mc

DM

DM


Torque Seminar

2

2

1mrJ

The mass moment of inertia J is a measure of the resistance that a body

presents to a rotary acceleration.

Mass moment of inertia

m r

m

m

Torque Seminar 24.05.2015, Page. 1Hottinger Baldwin Messtechnik GmbHKlaus Weissbrodt The nominal (rated) sensitivity The nominal (rated) sensitivity.

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