Cabinet cooling unit climate control example

This example shows the power supply and control connections of a Rittal cabinet cooling unit -EC1, used to maintain the required temperature inside the electrical cabinet.

The cooling unit is supplied through a dedicated two-pole circuit breaker -F3. The protected supply is connected to terminals L1 and L2/N of the cooling unit. The drawing also shows the separate PE and FE connections, providing the protective earth and functional earth connections required by the equipment.

The cooling unit includes a connection for an external door-operated switch -DSW1. This switch is connected to terminals 1 and 2 of the cooling unit and provides the door status signal. This allows the cooling unit to respond to the cabinet door being opened, according to its configured operation.

The cooling unit also provides a fault relay with terminals 3, 4 and 5. The relay contacts are connected to the PLC input I301.2, allowing the control system to monitor the cooling unit's fault status.

In addition, the auxiliary contact of circuit breaker -F3 is connected to PLC input I301.3. This provides feedback about the status of the cooling unit's supply protection.