Troubleshooting ESIE11-02
3–38 Part 3 – Troubleshooting
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4.9 Soft Starter (option EKSS) Thermal Protection
Introduction The PS S 25 (soft starter) is used in small chillers to reduce the starting current of the compressor.
The soft starter is equipped with an internal protection that prevents the softstarter from heating.
Functional
description
Inside the PS S 25, a heat sink is connected to the triac. The temperature of this heat sink is measured
internally in the soft starter.
When the temperature of this heat sink reaches 100°C, the thermal protection will prevent the
compressor from starting up after the start command is given by the digital controller.
Thermal protection
operation
The thermal protection operates as follows:
Ambient
temperature > 43°C
If the unit is operating at an ambient temperature of more than 43°C and a restart of the compressor(s)
is requested within 10 minutes after a stop, the unit may stop operating and no alarm is indicated on
the central controller.
This is because the soft starter module has switched to thermal protection. The thermal protection can
be reset by manually switching the power off and on again after these 10 minutes.
When the compressor
receives the start com-
mand...
If the heat sink temperature
has reached 100°C due to...
The compressor will...
The soft starter checks the
heat sink temperature.
■ High ambient conditions
■ Large switching rate
(e.g. more than six hours
an ambient temperature of
55°C inside the switchbox)
■ Other actions that cause
the heater sink
temperature to increase.
Not start up.
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