Omega Products TQ 503 Installation Manual

Operating Instructions

Rotary Torque Transducer

Model TQ 503 (with standard square connections)
Model TQ 503 X (including rangle measurement)
Model TQ 503 R (with shaft ends)

Operating Instructions no. 1333

Model TQ 503

Operating Instructions no. 1333

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Contents

1. Contents

2. Application and key features

3. Description

3.1 Mechanical design

3.2 Electrical design

3.3 Rotation angle measuring system (only version X)

4. Electrical connections

4.1 Description of interfaces

4.2 Installing the signal lead

5. Using the torquemeter

5.1 Version Q, X

5.2 Version R

6. Static calibration

6.1 Making a simple calibration device

6.2 Calculation example for lever arm length

7. Maintenance

8. Repairs

See datasheet for technical details.

Operating Instructions no. 1333

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2. Application and key features

· Torquemeter with strain gauges

· Signal transfer by sliprings

· Measurement of constant and variable torque

· Measurement of torque from the rotating shaft

· Integrated system for rotation angle measurement (only version X)

· Suitable for laboratory use and quality control

· Ideal for use with power tools

· Primarily suitable for low speed ranges

· Suitable for momentary measurement of torque (intermittent duty)

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3. Description

3.1 Mechanical design

Torquemeters type SD comprise a rotating shaft mounted on bearings inside a housing. The shaft has a
necked section - called the torsion zone - to which strain gauges are attached and connected in a full
bridge circuit. Sliprings and brushes provide the link between rotor and housing with two sliprings
carrying the electric power supply to the strain gauges on the rotating shaft. Two other sliprings serve to
transfer the measuring signals from the rotating shaft to the stationary housing. The full bridge circuit is
connected directly through the sliprings and brushes to the lead connector which is mounted on the
housing of the torquemeter.
In version X torquemeters an optical rotation angle measurement system is integrated. It consists of a
pulse disk on the rotating shaft with 360 light-dark stripes. Two light barriers are installed into the stator.
Inside the torquemeter there is a small electronics for processing of the angle pulses.

Square socket
(version Q / X)
or hexagon socket
(version H)
or shaft end with
feather key slots
(version R)

Shaft

Bearing

Brushes

Slip rings

Lead connector

Rotation angle
measuring system
(only version X / HA)

Housing

Square end

(version Q / X)

or hexagon end

(version H)
or shaft end with
feather key slots

(version R)

Bearing

Strain gauges

Torsion zone

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3.2 Electrical design

Shield

R4R3

R2 R1

S4S3S2S1

Version Q, R, H:
Version QA:
Version H

(special design):

U

B

 R1 ... R4 = Gauges for measuring mechanical strain
 S1 ... S4 = Sliprings with brushes

Signal leads

654213
KDCBAM
FDCBAE

Calibration

voltage

Operating Instructions no. 1333

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3.3 Rotation angle measuring system (only version X)

3

2

1

3

+5V0V

FEHG

Diagram showing the design of the rotation angle measuring system

1 rotating shaft
2 pulse disk
3 forked light barrier with LED and photo diode

0 V

4

4 operation amplifier

Features

- 360 light-dark stripes on the pulse disk

- two forked light barriers shifted by phase angle 90°

- pulse number proportional to the rotation angle

Operating Instructions no. 1333

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Adjustment for angle-pulse output (only version X)

with drive on square socket
sense of rotation cw

Output Pin G

Output Pin H

Label M for
Measuring side.
Side with bearings

W

drive side

View W:

Size RSize Q/R

Sense of rotation

Operating Instructions no. 1333

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4. Electrical connections

Lead connector

Shielded
lead

To power supply unit and display

Torquemeter (all versions)

 Shielded lead of 0,25 mm² (version X: 0.14 mm²) cross section
 Factory-calibrated with 5 m of lead. A change in length of 2.5 m will cause an error of

approximately 1 %

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4.1 Description of interfaces

E

ADF

Versions Q / R / H:

Function Pin Description Top view built-in plug

- Power supply 1 e.g. -6 V DC
+ Power supply 2 e.g. +6 V DC
Shield 3 not connected
+ Signal 4 2 mV/V approx. 350 W *)

- Signal 5 2 mV/V approx. 350 W *)

- Power supply 6 100% calibration
(Calibration voltage) causes 100% signal

Version X:

Function Pin Description Top view built-in plug

- Power supply A Strain gauge full bridge
+ Power supply B
+ Signal C

- Signal D
0 V E Rotation angle pulses

+ 5 V ± 10 % F
Pulse l, leading, TTL G
Pulse r, lagging, TTL H
0 V I

- Power supply K 100% calibration
(Calibration voltage) causes 100% signal
Shield M not connected

Version H (special design):

Function Pin Description Top view built-in plug

+ Power supply A e.g. +6 V DC

- Power supply B e.g. -6 V DC

- Signal C e.g. 2 mV/V approx. 350 W *)
+ Signal D e.g. 2 mV/V approx. 350 W *)
Shield E not connected

- Power supply F 100% calibration
(Calibration voltage) causes 100% signal

B

C

*) customized, see calibration certificate

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4.2 Installing the signal lead

 Do not run the lead parallel to power cables or control circuits.
 Do not place the lead close to equipment producing strong electromagnetic fields,

e.g. transformers, welders, contactors, electric motors, etc.

 If such situations cannot be avoided, run the lead inside earthed steel conduit.
 Make a loop in the lead when fixing it at the torquemeter so that it is not damaged by vibration.

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5. Using the torquemeter

5.1 Versions Q, X and H

 Torquemeters of version Q and X have square connections for plug-in tools acc. to DIN 3121
 Torquemeter of version H have hexagon connections acc. to DIN 3126, form E/F.

 The torquemeters are plugged on to the drive spindle as shown below.

Application examples:

motor /
el. or pneum.
wrench

Lead
connector

Torquemeter

Type SD

Versions Q / X Version H

Lead
connector

socket spanner / bit

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5.2 Version R

 The torquemeter is adapted to th measuring application by couplings.
 For a free floating installation we recommend two torsioally rigid half couplings.

Application example:

Torquemeter

Motor

Test
specimen

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6. Static calibration

This procedure requires the use of a calibration device with a lever arm and weights for producing
specific values of torque.

The calibration procedure is as follows:
a) Apply the rated value of torque to the torquemeter and then remove it again.
b) Adjust the zero reading accurately.
c) Apply a known value of torque to the torquemeter.
d) Adjust the displayed reading to the corresponding value.

Plotting a calibration curve

a) Calibrate the torquemeter as described above.
b) Apply torque in 1/10 steps up to the full rated value and then remove it again in the same way.

A delay of at least 30 seconds must be allowed between the individual 1/10 steps so that each
reading can stabilize before it is recorded.

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6.1 Making a simple calibration device

Torquemeter

Lever armLever arm

KK

Lever arm
bearing

K = Loose half-couplings

Counter bearing Lever arm bearing

(duplex)

Weight
(calibrated)

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6.2 Calculation example for lever arm length

Mt

L=

m x g

Mt = Torque
L = Length of lever arm required
m = Mass required
g = 9.80665 m/s² (= standard gravity - varies with location)

Mt

Example: m= 1 kg

Mt = 10 Nm

10 Nm s

2

è L = = 1,0197 m

1 kg x 9,80665 m

m

L

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7. Maintenance

 Gradual wear of the brushes and sliprings produces an electrically-conductive dust inside the

torquemeter which might cause an electrical short between the sliprings and cause instability of
the zero reading during rotation. Therefore, it is important to clean the torquemeter regularly.

 The recommended cleaning cycle is approximately 106 revolutions
 In order to clean the interior, loosen the 4 fixing screws and remove the cover plate
 Use a soft linen cloth, a fine hair brush or oil-free compressed air to clean the dust from the

sliprings and the spaces between them

 Carefully clean the brushes and the plastic part with the springs using a hair brush or oil-free

compressed air

 Version X: Be careful when cleaning, do not scratch the pulse wheel.
 Also clean the lead connector
 Measure the brush thickness; it should be more than 0.5 mm. New brushes can only be fitted at

the factory.

 Replace the cover plate carefully and re-tighten the fixing screws
 Check the torquemeter:

Zero reading stable during rotation.
Produce a torque by twisting the meter by hand and note the reading.

 If the torquemeter is used for precision work it should be recalibrated every year (either at the

factory or by means of a suitable calibration device)

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8. Repairs

Fault Cause Remedy

Shaft stiff to turn Bearing defect due

to:
a) Torsional or
flexural vibration
b) High axial or
radial loads
c) Worn bearings
d) Bent shaft

Zero shift less than
2%

Zero shift between
approx. 2 and 5% of
full scale

Hysteresis between
clockwise and
anticlockwise torque

Torsional vibration
Torsional shock

Torquemeter has been
overloaded
Torsional vibration
Torsional shock

Torquemeter over­loaded by high
alternating loads or
torsional vibration

Return to factory

The zero reading can
be readjusted at the
display

The zero reading can
be readjusted once at
the display

Return to factory

Zero unstable during
rotation

Angle pulses roll out
(only version X)

Sliprings and/or
brushes dirty

Pulse disk and optical sensor
are soiled by coal dust

Operating Instructions no. 1333

Open and clean the
torquemeter
(see section 7)

Clean carefully

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