Power measurement on motor with 2 or 3 current transformers
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WARNING: Risk of electric shock! If you do not connect terminal point N with the neutral conductor of your mains supply, you have to earth terminal point N, in order to avoid dangerous overvoltages in the event of a fault with a current transformer! |
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Attention! Risk of device damage! Avoid confusing the current and voltage circuit during connection, since the direct connection of mains voltage to the terminal points for the current transformers (typical input resistance 220 mΩ) would destroy the power measurement terminal! |
EL3443
- The voltage is measured via the connections L1, L2 and L3.
- The current is measured with two current transformers (e.g. the SCT series from Beckhoff) via the connections IL1 and IL2.
- The sum of all currents in the 3-phase mains network is 0. The value in circuit IL3 can be obtained accordingly by wiring the EL3443.
In the circuit shown above (Fig. EL3443, power measurement with 2 current transformers on a motor), ensure that the three-phase system is either earth-free or has an earthed star point. Alternatively a transformer can be included in a Yy0 circuit.
EL3453
- The voltage is measured via the connections L1, L2 and L3.
- The current is measured with three current transformers e.g. the SCT series from Beckhoff) via the connections IL1, IL2.and IL3
In the circuit shown above (Fig. EL3453, Power measurement with 3 current transformers on a motor), ensure that the three-phase system is either earth-free or has an earthed star point. Alternatively a transformer can be included in a Yy0 circuit.