Eaton Cutler Hammer MN05001002E Installation Manual

Intelligent Technologies QCPort System Install ManualNovember 2005MN05001002E For more information visit www.eatonelectrical.com Page 21Sizing a Power SupplyIt is important to verify that the power supply is properly sized for the load and the lengthof the QCPort system. To calculate if the placement and the size of the power suppliesare adequate, refer to the examples in the Using the Sizing Calculation on page 23.Supplying PowerFollow these guidelines to protect your nodes and to achieve the best results whensupplying power to the QCPort cable system.• Use power supplies rated at 24V.• Select a power supply that provides sufficient current for all attached nodes.• Make sure you derate the power tap and the power supply for the expectedtemperature using the manufacturer’s guidelines.• Use a power supply that has its own current limit protection.Adjusting the ConfigurationWhen the sections have a voltage drop less than 4.65V, your configuration will operateproperly. Ideally, the voltage drops for each section should be within 10%. If one sectionhas a substantially greater voltage drop than the other, you should attempt to balance theload of the cable system by moving the power supply or nodes. Some ways to makeyour system operational include the following:• Shorten the overall length of the cable system.• Move the power supply in the direction of the overloaded section.• Move devices from the overloaded section to another section.• Move higher current loads as close to the supply as possible.• Add a second power supply to the cable system.• Break the QCPort system into two separate networks to reduce the number ofnodes on each.