23.06.2017 Manual - IBExU 14 ATEX 1281 U - IECEx IBE 14.0058 U - PR-SPA-EX-WKF Page 2 of 11
4.2 Installation in the slot of an electrical machine (V3)
Temperature sensors of type PR-SPA-EX-WKF are specially designed for the assembly into blind
hole drillings in electric motors (generators) or other electrical machinery.
The assembly / the installation can be done with a specific moveable fitting with Teflon, brass or steel
clamp ring, aligned to the protection pipe diameter, or with a bayonet cap system.
If moveable fittings are used the nominal length can be matched to the requirements on-site.
The protection pipe of the thermometer must be mounted protected along its full length (e.g. in a blind
hole- or through bore-hole).
Bending loads (flexing) as well as mechanical loads on the temperature sensor (protection pipe and
cable exit) during installation and operation must be avoided.
During installation one has to pay attention that no damage occurs to cable and insulation.
The supply lines (connecting wires) have to be installed strain-relieved.
The sensor may be operated only in according to regulations and in undamaged, clean state.
The temperature sensors must be connected to the local potential equalization.
The thermometers don’t need to be grounded in the case of a completely insulated protection pipe. If
a clamp fitting is used the clamp ring must be made of Teflon.
During mounting and installations at and with the sensor, as well as during the on-site installation, the
national and international safety- and accident prevention regulation must be observed.
For long supply lines the specific length dependent capacities and inductances have to be observed.
The special conditions of the type examination certificate have to be observed.
The sensor user must specify the used protection type and document it carefully.
4.3 Usage outside the winding of an electrical machine
At this type of use, wherein the sensor is in direct contact with the explosive atmosphere are the self-
heating and the resultant increase of the surface temperature be observed.
Maximum surface temperature of the
equipment
Ignition temperature of the
flammable materials
4.4 Self-heating
When measuring the electrical resistance value, the current flows through the temperature sensor.
Depending on the external influences, this causes power dissipation and thus a self-heating of the
temperature sensor. Since a measuring current of 1 mA is generally not exceeded, the power dissipation
of a Pt100 is in the range of a few tenths of a milliwatt and normally does not produce any significant
measuring error. Otherwise, the self-heating must be observed so that the permissible maximum
temperature is not exceeded and measurement errors are avoided.
