Artesis eMCM - 2. Appendix 2: Current and voltage sensor selection; 3. Appendix 3: Connection Diagrams

52
2. Appendix 2: Current and voltage sensor selection
Voltage transformers, current transformer and current sensors must meet local standards and
regulations. For North America, current and voltage transformers must be certified by an OSHA
appointed NRTL to appropriate UL or CSA - product safety standards.
When selecting a current sensor, both the maximum current the motor will handle in practice and
the type of motor drive used should be considered. Systems employing an inverter will generally
limit initial inrush to a maximum of about 150% of nominal current.
With a soft-starter system this limit will probably be 400%. Sensors must be able to withstand the
maximum expected inrush currents and should be selected accordingly.
Sensors should be selected such that the nominal motor values for current and voltage are around
20% of the corresponding sensor rating.
Voltage transformers should be 1% accurate or better with 100V, 110V, or 120V secondary
voltage.
3. Appendix 3: Connection Diagrams
3.1 Low voltage line driven motors with current transformers (V
L-L
<690)