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Transmission Systems Architectures and Performances
Published in Iannone Eugenio, Telecommunication Networks, 2017
Hot-swap capabilities: Compact PCI, PCI-X, VME64, VME64x. To hot swap means to leave the bus interface component on, or in a known state while removing or inserting a card into the system. Hot swapping or live insertion is important for customers who require systems with zero downtime. All the major protocols are adopting specifications to support hot-swap capabilities. Compact PCI and VME64 both include special mechanical configurations in the connector to make and break the ground, prebias, control, and VCC connections before the data pins touch. This allows a card to be precharged and reduces insertion transients associ-ated with noise and voltage spikes.
Understanding Crossbar Switch Fabrics
Published in James Aweya, Switch/Router Architectures, 2019
In addition to duplicate data paths, network device hardware can be made more reliable by adding hot-swappable modules, such as dual power supplies, cooling fan trays, alarm functions, etc. For added reliability, all power supplies (AC or DC) in the system can be designed to be load-sharing and hot-swappable. Hot-swapping, sometimes called online insertion and removal (OIR) or power-on servicing, is a feature that permits the removal (or replacement) or addition of modules or cards to a running system without interrupting its power supply, entering commands on a console, or causing other system interfaces or software to shut down.
High-Performance Switch-Routers
Published in James Aweya, Designing Switch/Routers, 2023
If a system does not support hot swapping of line cards and a line card is removed from a slot, this action may disrupt the traffic being processed by the system, and in the worse situation, the system might reboot. It is therefore important to know if a particular system supports hot swapping because, removing a card from a system that does not support such capabilities can cause permanent damage to the card, or worse, the whole system.
Analysis and Design of a Smart Startup Method for a Single-Phase BLDC Fan Motor
Published in Electric Power Components and Systems, 2018
Zong-Hong Tang, Yie-Tone Chen, Jiang Luli, Ruey-Hsun Liang
The BLDC motors in fan applications frequently have a fan with a self-rotating impeller before startup. The self-rotation of the fan impeller is usually caused by the external thrust of the wind. Some server systems need the fan array for cooling; the multifan application is required to provide the function of hot-swapping due to the demand of on-line maintenance. It will form an air countercurrent passage environment when a fan in the fan tray needs to be exchanged or needs to be restarted in some abnormal situations, and the reverse wind flow will drive the fan impeller to generate a reverse self-rotation. On the other hand, in some outdoor applications, the fan impeller also has high chances to be driven by an external wind force to spin before startup. The speed of reverse self-rotation is usually random and unfixed and depends on the system’s air flow impedance. Taking the application of a fan array as an example, the maximum reverse speed of the one which needs to be restarted can possibly reach 70–80% of the rated speed when the other fans are running at full speed. However, directly powering up a fan motor will probably damage the motor controller when the rotor is in reverse self-rotation before starting. Due to the reverse self-rotation, motor winding will produce inverted induced energy which will cause the motor controller to be confronted with a big challenge in electrical stress, if the induced power cannot get the suitable processing during the fan startup.