Liquid filled Thermometers
Description and general specifications
Liquid filled contact thermometers
Operating instructions and maintenance
Finished product quality control tests
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Description and general specifications.
These instruments are used to detect the temperature in the oil filled transformers and are made for outdoor
mounting in as well tropical or artic climates (ambient temperature range : -30 / +70°C). All components are
made of corrosion resistant or surface treated materials.
Casing : aluminium alloy with powder painting
high protection degree. On request case can be
provided with an air breather device.
Nominal diameter :
100mm. or 150mm.
Temp. sensing system :
expansion type (liquid filled system), compensated for ambient temperature changing by
means of a bimetallic spring.
Capillary protection :
• protective copper tubing
• flexible galvanized iron + PVC tubing
• flexible AISI 304 tubing.
Locking clear window : glass.
Locking ring : nickel plated, transparent coated.
Standard measuring ranges :
-20 / +130°C
0 / +120°C 0 / +150°C
0 / +200°C
Measuring accuracy :
1,5% of full scale value.
Bulb : brass or stainless steel
Liquid filled contact thermometers.
These thermometers are equipped with electrical contacts of air type (silver contacts).
On request the electrical contacts can be equipped with a little magneto to avoid uncertain commutations
when the instruments are subject to vibrations.
The contacts can be normally open or normally closed. The opening and closing of contacts are of slow action type.
ELECTRICAL CONTACTS MAKING AND BREAKING CAPACITY :
ELECTRICAL CONTACTS STANDARD EXECUTION
Volt
Alternating Current
Direct Current
Inductive
Load
23mA
380
28mA
15mA
220
46mA
40mA
22mA
110
90mA
80mA
45mA
50
170mA
130mA
70mA
Volt
380
220
110
50
MAGNETIC ELECTRICAL CONTACTS
Alternating Current Direct Current Inductive Load
70mA
80mA
45mA
140mA
125mA
65mA
275mA
240mA
130mA
500mA
380mA
200mA
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Insulation test : 2000V 50Hz between terminals
and earth for a 60 seconds time.
Mechanical protection degree : IP 55.
THERMOMETER 1144/S
DRWG. N. 1144
1144/S
1184/S
1184/S
1186/S
1186/S
THERMOMETER 1147/S
THERMOMETER 1186/S
DRWG. N. 1186
DRWG. N. 1184
nom.
Ø
100
100
150
100
150
Elastic suspension : this device is a vibration
damping system able to minimize the effects of
machine vibrations on the instrument (Drwg.
N.1231).
DRWG. N. 1147
THERMOMETER 1184/S
Type
Measuring accuracy : 1,5% of full scale value.
A
B
C
121
121
172
121
172
58
90
91
90
91
79
79
103
/
/
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THERMOMETER 1187-10
nominal diameter 100
DRWG. N. 1187-10
THERMOMETER 1187-15
nominal diameter 150
DRWG. N. 1187-15
THERMOMETER 1187-10 ES
nominal diameter 100
DRWG. N. 1187-10-ES
THERMOMETER 1187-15 ES
nominal diameter 150
DRWG. N. 1187-15-ES
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Operating instructions and maintenance.
Operating instructions :
Mounting :
a) rigid stem thermometers ( types 1144/S - 1184/S - 1186/S )
fix the connection on the thermometer pocket by means of a spanner. Attention don't try to tighten the connection by rotating the thermometer's head as you may damage it !
Once the connection is fixed you may need to position the dial to get the best readability. The positioning can
be made by means of the swivel nut of the thermometer.
b) thermometers with capillary (types 1187/S ) : fix the thermometer's head to the machine by means of the
back flange or of the elastic suspension. Then fix at regular distances the capillary to the machine wall or
cover and position the bulb inside of the thermometer pocket. Finally tighten the connection
Contact setting : remove the locking ring
remove the glass
rotate the frictioned setting pointers till are positioned at the desired set points value
put the glass into its seat taking care that the sealing O-ring is correctly located under
screw the locking ring
BLACK COLOR = ALARM CONTACT
RED COLOR = TRIP CONTACT
Cable layout : Remove locking ring and glass as done for contacts setting
connect the terminals of the contact by taking care that black screws correspond to black pointer contact and
red screws correspond to red pointer contact
Reposition the glass and mount the locking ring
Maintenance :
No particular maintenance is required. Only, on regular basis, schedule inspections to verify correct function
and calibration.
Typically a check of the precision must be done after 24 months and the check for contact functionality must
be done at least once a year.
In case the transparent is dirty, thus reducing the readability of the dial, you can clean it with a soft cloth, water and soap.
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Finished product quality control tests.
Thermometers without electric contact for distribution transformers
Instrument calibration : carried out through thermostatic baths controlled by a microprocessor based monitoring unit.
The procedure varies according to instruments scale.
The calibration procedure, being the thermometer scale = 0 / +120°C is made by using 5 different baths set
at the following temperatures :
bath 1 = 0°C
bath 2 = 20°C
bath 3 = 50°C
bath 4 = 100°C
bath 5 = 115°C
Calibration procedure :
Step 1 : a check is carried out to see whether the temperature taken by the instrument under test differs from
that taken through the sample sensor by more than the 70% of the maximum allowed instrument
reading tolerance value. This test is performed by sequentially plunging the thermometer bulb
into successive temperature increasing thermostatic baths : 0°C / +20°C / +50°C / +100°C /
+115°C.
Step 2 : the instrument is heated until the instrument pointer exceeds by 20% the angular full scale value.
Step 3 : step 1 is repeated, but inversely.
Check of instrument mechanical protection degree : IP 55
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Finished product quality control tests.
Thermometer with electric contacts (air type silver contacts) for distribution transformers
Instrument calibration : carried out through thermostatic baths controlled by a computer system.
The procedure varies according to instruments scale.
The calibration procedure, being the thermometer scale = 0/+120°C is made by using 5 different baths set at
the following temperatures :
bath 1 = 0°C
bath 2 = 20°C
bath 3 = 50°C
bath 4 = 100°C
bath 5 = 115°C
Calibration procedure :
Step 1 : a check is carried out to see whether the temperature taken by the instrument under test differs from
that taken through the sample sensor by more than the 70% of the maximum allowed instrument
reading tolerance value. This test is performed by sequentially plunging the thermometer bulb
into successive temperature increasing thermostatic baths : 0°C / +20°C / +50°C / +100°C /
+115°C
Step 2 : the instrument is heated until the instrument pointer exceeds by 20% the angular full scale value.
Step 3 : step 1 is repeated, but inversely.
Manual inspection of the electric contact actuation : in every point of the scale.
Tripping status control of electric contacts : performed via visual indicators mounted on a panel-board.
The bulb is immersed in a thermostatic bath.
A Temperature monitoring and control unit changes the temperature inside of the bath and by means of said
panel-board the operator verifies the commutation tolerance, the commutation differential, the electrical circuits of each contact.
Check of instrument mechanical protection degree : IP 55
I EDITION AUGUST 2006
Insulation test : carried out by means of a microprocessor controlled testing unit.
Terman '90 S.r.l., Via Ghisalba, 13-20/21, 20021 Bollate (MI) – Italy. Tel: +39 02 38 30 37 12, Fax: +39 02 38 30 37 19,
E-Mail [email protected], www.terman.com
C.F./P. IVA IT 09970270154 – C.C.I.A.A. 1332904 – Trib. Milano Reg. Soc. 302729 – Cap. Soc. € 119.000
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