Fig. 112 Power Measurement With 2 Current Transformers On A Motor - Beckhoff EL3773 Documentation

Commissioning
Fig. 112: Power measurement with 2 current transformers on a motor
In the circuit shown above (Fig. Power measurement with 2 current transformers on a motor), ensure that the
three-phase system is either earth-free is or has an earthed star point. Alternatively a transformer can be
included in a Yy0 circuit.
Power measurement in a single-phase mains network with ohmic consumers
• The voltage is measured via connections L1, L2, L3 and N.
• The current is measured via three current transformers [} 123] and the connections I
(star point of the current transformers).
WARNING: Risk of electric shock!
Bring the Bus Terminals system into a safe, de-energized state before starting mounting,
disassembly or wiring of the Bus Terminals.
WARNING
Attention! Risk of device damage!
Avoid confusing the current and voltage circuit during connection, since the direct connec-
tion of mains voltage to the terminal points for the current transformers (typical input resis-
Attention
tance 220 mΩ) would destroy the power measurement terminal!
104 Version: 2.5
, I , I and I
L1 L2 L3 N
EL3773