ABB MNS R Manual De Instalación página 19

7. Auxiliary circuits
8. Anticondensate heater
• In case of particular apparatus configuration, it is possible that the previous inspections must be
integrated with others suggested by the technician responsible for the apparatus.
• Check that the current transformer secondary winding is connected to the related protective and/or
measuring amperometric circuit, then remove any possible short-circuit connections.
• In case the voltage transformer secondary winding must be connected to switchboard external equipment,
check for the following conditions, to avoid overloads or short-circuits in the voltage transformers:
- Check that the total comsumption of the equipment is not superior to the transformer capacities.
- Check for incorrect connections (also provisional) in the measuring circuit or connections not in
accordance with the switchboard connection and other units (supply switchboard, subswitchboards,
control or operating desks, etc.).
- Check that only one phase of the voltage transformer secondary winding is earthed.
• At the end of the preliminary test, carry out the following operations:
- Open and isolate all the circuit breakers
- Remove any testing connections
Close all doors of the circuit breakers and measuring cells
Check for internal metal segregations (according to the design constructive shape) of the external
closing panels
- Check that the different mechanical and electrical interlocks (possibly deactivated to carry out start
test with switchboard not powered) have been restored.
• Feed the control circuit
• Close the circuit breakers (according to system requirements), and ensure that any related function
operates regularly
• Check the correct operation of the auxiliary instruments.
Respect the general safety rules
According to the diagram, check the
functionality and the operation logic
sequences of the auxiliary circuits
• Feed the circuit
• Adjust the thermostat to the
higher temperature allowed
• Check that the heater
temperature raises
• Adjust the thermostat so that
the temperature inside the
switchboard is always higher than
the outside ambient temperature
(approximately 35° C)
Before performing this
inspection, check the
calibration of each relay of the
switchboard
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