Introduction; Brief Description - JUMO ATH-SE Series Operating Manual

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Introduction

2 Introduction
2.1

Brief description

Thermostats are used to control and monitor thermal processes. The devices of the ATH.-SE type series
are available as temperature monitors TW, safety temperature monitors STW (STB) and safety tempera-
ture limiters STB. In the event of a malfunction, the STB switches the monitored machine line to an op-
erational safe status.
Surface-mounting thermostats operate according to the fluid expansion principle, a microswitch is used
as an electrical switching element.
Switching function
Temperature monitor TW and safety temperature monitor STW
If the temperature on the temperature probe exceeds the limit value, the electrical circuit is opened by a
microswitch. When the limit value falls below the set limit value (by the switching differential), the switch
is returned to its initial position.
Restart lock at safety temperature limiter STB
If the temperature at the temperature sensor exceeds the set limit value, the electrical circuit is opened
and mechanically locked. After falling below the limit value by approx. 10 % of the temperature range,
the switch can be unlocked manually.
Use of the safety temperature monitor STW as safety temperature limiter STB
In this case, the circuit following the thermostat must comply with DIN EN 14597 and VDE 0116.
Self-monitoring for safety temperature limiter STB and safety temperature monitor STW (STB)
If the measuring system is destroyed (i.e. if the expansion fluid escapes) the pressure in the membrane
of the STB and STW (STB) drops and permanently opens the electrical circuit. Unlocking is then no lon-
ger possible. When the STB sensor cools down to the negative temperature range, the circuit opens, but
must be manually unlocked by the reclosing button when the temperature rises. The STW (STB) auto-
matically restarts.
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