Installation and Operating Manual / Version 10 / 3626-011500
en
/ Protection class 0: public / 2017-12-15
BTS, non-contacting thermal switch unit
2.1 Switching element
The switching element is a passive component (ordinary electrical equipment). It is
inserted into the outer wheel or into the turbo coupling shell. The result is a thermal
contact between the switching element and the turbo coupling with the operating fluid.
A coil and a thermostatic switch are integrated in the switching element. The switching
point of the thermostatic switch corresponds to the response temperature of the
switching element.
Below the nominal response temperature, the thermostatic switch is closed and
bridges the coil. Above the nominal response temperature, the thermostatic switch
opens and interrupts the circuit. When the temperature decreases, the thermostatic
switch connects again the circuit. The BTS is again ready for service (it resets
automatically).
2.2 Initiator
The initiator has been designed as polarized two-wire sensor. It works to the inductive
sensor principle.
An electric oscillator is integrated in the initiator which produces a high-frequency
oscillation. The oscillator has an oscillating circuit as element determining the
frequency, comprising a coil and a capacitor.
The oscillating circuit coil is located in the sensor head. An electromagnetic alternating
field leaves the sensor head via this coil.
2.3 Evaluator
The evaluator is an electronic unit recording the electric pulses and evaluating the
period between the pulses.
The evaluation starts either by switching on the supply voltage or by an external
trigger signal.
After starting the evaluation, monitoring of pulses must be interrupted for an
adjustable period of time (start-up bypass time).
A relay with changeover contact will be released if the number of pulses per unit of
time drops below a certain value.
2.4 Isolating switch amplifier
The isolating switch amplifier transmits digital signals from the potentially explosive
area.
Sensors or mechanical contacts may work as transducing sensor.
The intrinsically safe inputs are safely isolated from the output and power system.
temperature
Chapter 3.1
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