C-mac® FPA90 is monitoring the consumed power on symmetrical 3-phase loads like motors, etc.
The power monitoring uses the formula P = √3 x U x I x cos
The unit has a built-in current transformer, making it possible to monitor loads up to 460 VAC - 80 A direct.
The converter is connected to the same 3-phase supply voltage as the load, and one of the phases are let through the hole in the unit, for monitoring of the load current.
If the load current exceeds 80 A, you can use an external current transformer, and the secondary from the transformer is then let through the hole.
The wanted metering range (in kW) is adjusted on 3 rotary switches on the front of the unit. If you use an external current transformer, you must divide the power setting with the ratio of the transformer.
In order to ensure the correct function it is important to connect the converter as shown on the next page, i.e. the metering current must be the phase, which is connected to terminal 1, and the current direction must be correct too.
The converter is supplied with analogue current and voltage outputs and a pulse output, and the outputs are in maximum, when the monitored power is the same as the selected metering range.
All outputs are galvanically separated from the supply voltage.
In addition the unit has 3 digital inputs for the selection of analogue output signal, pulse ratio and input filter.
The input filter is used if the load is very unstable, in this way, the output signal is more stable.
The unit is also supplied with 3 LED indications.