Messko ZT-F2 Instrucciones De Montaje Y Servicio página 4

English
1. Description of the product
The ZT-F2 transformer temperature transmitter can only be
used in conjunction with a TRASY2 series dial thermometer.
It is used to represent the thermal image (= winding
temperature) in the transformer.
The winding temperature is measured indirectly. The
temperature gradient between the winding and the coolant
is dependent on the current in the winding: the measuring
transformer's secondary current is proportional to the
current in the winding of the transformer. The measuring
transformer's secondary current supplies a heating resistor in
the ZT-F2 transformer temperature transmitter and thus
causes the display indicating the actually measured oil
temperature to rise (= temperature gradient) in accordance
with the load on the transformer.
The winding temperature is simulated in the ZT-F2 and the
temperature gradient between the oil and winding is set. The
winding temperature is displayed on a dial thermometer, the
temperature detector of which is incorporated into the
ZT-F2. The measured value can also be transferred to a
moving-coil or digital display, for example, via the integral
Pt100 resistor or a 4 – 20 mA analogue output.
IMPORTANT !
Measuring devices are sensitive, so please protect
all the parts against falling, impact or shock.
The ambient temperature must not exceed 80 °C.
The temperature transmitter is not crush proof.
IMPORTANT !
The operating and assembly conditions specified in
these Assembly and Operating Instructions must be
followed exactly.
2. Installation conditions and testing
The ZT-F2 transformer temperature transmitter is designed to
be installed in a DIN 42554 thermometer pocket. The
thermometer pocket must be located on the transformer
cover, near the largest oil flow. This will ensure a satis-
factory heat exchange between the coolant, thermometer
pocket and the temperature detectors in the ZT-F2. The
thermometer pocket must be 2/3 full with oil in order to
ensure a correct transfer of heat. If these requirements are
fulfilled, the winding temperature (temperature gradient) will
be displayed accurately. If you wish to test the ZT-F2
transformer temperature transmitter before fitting it to the
transformer, then you must create the same conditions in the
test set-up as occur on the transformer (see "Testing
conditions" box below).
Testing conditions:
1. Controlled movement of the oil bath.
2. DIN 42554 thermometer pocket fitted in the oil bath.
3. Thermometer pocket 2/3 full with oil.
4. ZT-F2 fitted in the thermometer pocket.
5. Pt100 connected to terminals 3+4 (5+6 are optional).
Optional: connect 4 – 20 mA output.
Insert the detector of the pointer-type thermometer
until it reaches the stop (approx. 175 mm).
6. The bath temperature should not exceed 30 °C,
otherwise the heat emitted via the double joint would
distort the transformer conditions.
7. Allow the sensor to adapt to the bath temperature
for at least 30 minutes.
8. The measuring cycle until the jump temperature is
reached should take at least 45 minutes.
3. Pointer-type thermometer
The ZT-F2 can be combined with various pointer-type
thermometers and analysis instruments.
Always follow the instructions provided when fitting such
instruments.
4. Assembly
4.1 Assembling the ZT-F2 transformer
temperature transmitter
The ZT-F2 transformer temperature transmitter is designed
to be fitted in a DIN 42554 thermometer pocket.
IMPORTANT !
Never fill the ZT-F2 transformer temperature
transmitter with oil. Only the thermometer pocket
should be filled with oil.
Fill the thermometer pocket with oil until it is 2/3 full.
To assemble, screw the bottom nut of the double joint
(figure 1, item 3) into the thermometer pocket. Insert and
straighten the immersion tube (figure 1, item 4) of the
ZT-F2 transformer temperature transmitter. Tighten the
double joint.
IMPORTANT !
Do not apply force to turn the ZT-F2 transformer
temperature transmitter. Always loosen the
double joint.
4.2 Installing the temperature bulb of the
pointer-type thermometer
Unscrew the cover of the ZT-F2 transformer temperature
transmitter (figure 1, item 1). Unscrew the Pg16 pressure
screw. Push the pressure screw, thrust collar and gasket
over the temperature detector (9.5 mm diameter) and the
capillary tube. Thread the temperature detector 40 – 50 cm
through the middle heavy-gauge pressure joint until it
reaches the stop (at a depth of approx. 175 mm) in the
temperature detector sleeve of the ZT-F2 transformer
temperature transmitter. Pull the capillary tube until it is
straight and fix in place. Tighten the heavy-gauge pressure
joint.
4.3 Connecting the current transformer
Connect the current transformer to terminals 1 + 2 of the
ZT-F2 transformer temperature transmitter. The rated
secondary current should be 1.5 to 2 A. Use a primary-side
device if the current intensity is higher or lower.
5. Connecting the remote indicator
5.1 Pt100 measuring resistor
The ZT-F2 is equipped with a Pt100 measuring resistor
conforming to IEC 751. Connect the resistor to terminals
3 + 4 (see also terminal connection diagram on page 12,
figure 4).
May be equipped with two Pt100
Optional
measuring resistors
The length of the connecting cables
Length of
will depend on the specification for
connecting cable
the signal conditioner or display
device to be connected.
(e.g. Pt-MU 100Ω per cable)
If the display device is designed
3 or 4-wire
designed for 3 or 4 wires, connect
configurations
connect the sensor line and the
equalising line to the same terminal
(see terminal connection diagram,
page 12, figure 4).
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