4. Operation
WARNING: It is not advised to connect two UPS in parallel when using individual transformers for
each UPS.
4.1 Over-Temperature Protection
4.1.1 Over-Temperature Warning LED Light (Red)
The transformer includes two warning LED lights on the top portion of the front panel: one light for the input transformer and
one light for the output transformer. The corresponding warning light will turn ON when the secondary side of the input (T-in)
or when primary side of the output (T-out) transformer reaches a temperature of 160°C ± 5°C, i.e. a range of 155°C to 165°C
(311°F to 329°F). The warning light turns OFF when the transformer cools to a temperature of 125°C ± 5°C, i.e. a range of
120°C to 130°C (248°F to 266°F).
4.1.2 Over-Temperature Protection Relay and Thermal Switch
The transformers include an over-temperature protection relay and thermal switch on the secondary sides of the input (T-in)
and on the primary side of the output (T-out) transformer to protect the transformer from overheating.
• Input Transformers (T-in): If the secondary side of the (T-in) input transformer reaches temperatures of 160°C ± 5°C,
i.e. a range of 155°C to 165°C (311°F to 329°F), an over-temperature protection relay and thermal switch will activate and
will open the breaker on the secondary side of the transformer. Once the transformer temperature has cooled down to
125°C ± 5°C, i.e. a range of 120°C to 130°C (248°F to 266°F) the warning LED light will turn OFF, and you may manually
re-activate (close) the output breaker on the transformer to restart normal operation.
• Output Transformers (T-out): If the primary side of the (T-out) output transformer reaches temperatures of 160°C ± 5°C,
i.e. a range of 155°C to 165°C (311°F to 329°F), an over-temperature protection relay and thermal switch will activate and
will open the breaker on the primary side of the transformer. Once the transformer temperature has cooled down to
125°C ± 5°C, i.e. a range of 120°C to 130°C (248°F to 266°F), the warning LED light will turn OFF, and you may manually
re-activate (close) the input breaker on the transformer to restart normal operation.
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