DellPowerEdge R715 Technical Guide 153.8 Internal Chassis ViewFigure 6. Internal Chassis View3.9 Rails and Cable ManagementSliding ReadyRailsTM for 4-post Racks support the following: Toolless installation in 19‖ EIA-310-E compliant square or unthreaded round hole 4-post racksincluding all Dell 42xx and 24xx racks (threaded 4-post racks require the static ReadyRails™kit or third-party conversion kits available through Dell Software and Peripherals). Full extension of the system out of the rack to allow serviceability of key internal components Optional cable management arm (CMA)Measurements and adjustment ranges for the rack: Rail depth without the CMA: 755 mm (with outer CMA brackets removed) Rail depth with the CMA: 883 mm Square-hole rack adjustment range: 686–883 mm Round-hole rack adjustment range: 672–876 mm Threaded-hole rack adjustment range: 651-897 mm3.10 FansSix hot-swappable fans are mounted in a fan gantry that is located in the chassis behind theprocessors. Each fan has a blind mate 2x2 connector that plugs directly into the CPU Board. There isan additional fan integrated in each power supply to cool the power supply subsystem and alsoprovide additional cooling for the whole system.The Embedded Server Management logic in the system monitors the speed of the fans. A fan failureor over-temperature in the system results in a notification by iDRAC6. All system fans are pulse widthmodulated fans. Redundant cooling is supported with one fan failing at a time.