Selecting and wiring principle of control cables in the inverter control cabinet
2. For Class Ⅱ signals should be shielded, Class Ⅱ signal for controlling, interlocking signal into the mold, open into the signal, it must be shielded cable, preferably shielded twisted-pair cable. Prohibiting the use of more than one core cable in the portion of the core wire for the transmission of class Ⅰ or Ⅱ class signal, the other part of the core lines for transmitting signals Ⅳ Ⅲ class or classes.
3. For Ⅳ class signal is strictly prohibited and Ⅰ, Ⅱ class tied together signal traces should be treated as a 220V power line, class Ⅳ signal and power cables together with traces should be shielded twisted-pair cable. The absolute prohibition of high-power switch output signal lines, power lines, power lines, cable and Frequency Control System Ⅰ, Ⅱ class signal cables parallel bundle.
4. For Ⅲ class signal, allowing the 220V power line traces together (ie the same class Ⅳ signal), but also with Ⅰ, Ⅱ class together with the signal traces. But class Ⅲ signals must be shielded cable, preferably shielded twisted pair cable, and with Ⅰ, Ⅱ class signal cables more than 15cm apart. It prohibited the same signal several wires are distributed in different several cables (such as the three-wire RTD)
In the field cabling must be effectively separated from easy to produce interference cables Ⅲ, type Ⅳ signal cable, power lines, etc., so that it Ⅰ, Ⅱ class signal cables laid site is maintained at a safe distance (eg 15cm above).
Signal and power cables should be different trunking alignment, when entering the inverter cabinet, should also be away from each other as possible. When these two cables can not be routed separately to meet the requirements, they must be shielded cable (shielded or twisted pair cable), and shall meet the following requirements:
2. When the signal and power cables vertically or horizontally when installed separately, the spacing between the signal and power cables should be more than 15cm. For some disturbances particularly large applications, such as contact voltage is AC 220V power supply cable, the current in the inductive load 10A above, but when the power cable is not shielded, so it requires a direction perpendicular to the signal cable spacing must more than 60cm.
3. When two cables perpendicular, if the power cable is not shielded, in 1. 6mm in thickness is more than covered the iron cross section.
In order to reduce interference from analog converters and other equipment, should control the drive signal line and power circuits (main circuit and sequence circuit) traces separately. Distance should be more than 30cm. Even in the control cabinet, also have to maintain this connection specification. The signal cable is no longer than 50m, signal line protection metal pipe or a metal hose has to be extended to the control terminal of the inverter to ensure complete separation of signal lines and power lines. Analog control signal lines should use shielded twisted pair cable, wire gauge is 0.5 ~ 2mm2. When wiring cable stripping it as short as possible (5 ~ 7mm), while the subsequent stripping shield wrap with insulation tape to prevent contact with the shield and other equipment and the introduction of interference.