CSI SECTION 16611 STATIC UNINTERRUPTIBLE SYSTEM
2.7AUTOMATIC BYPASS
A.As part of the UPS, a system automatic bypass switch shall be provided. The system automatic bypass shall provide a break <11Ms transfer of the critical load from the Inverter output to the automatic bypass input source during times where maintenance is required, or the inverter can not support the critical bus. . Such times may be due to prolonged or severe overloads, or UPS failure. The additional manual bypass switch will have a no break transfer of critical loads from Inverter output to the manual bypass switch which will correspondingly engage the automatic bypass switch driving it into bypass position. The UPS shall constantly monitor the output current, as well as the bypass source voltage, and inhibit potentially unsuccessful transfers to automatic bypass from taking place.
B.The design of the automatic bypass switch power path shall consist of a heavy duty electromechanical bypass contactor with a continuous duty rating up to 100A.
C.Automatic Transfers: An automatic transfer of load to bypass shall take place whenever the load on the critical bus exceeds the overload rating of the UPS. Automatic transfers of the critical load from bypass back to normal operation shall take place when the overload condition is removed from the critical bus output of the system. Automatic transfers of load to bypass shall also take place if for any reason the UPS cannot support the critical bus.
D.Manual Transfers: Manually initiated transfers to and from s bypass shall be initiated through the UPS display interface or by engaging the manual bypass switch on the front of the unit.
E.Overloads: The automatic bypass shall be rated and capable of handling overloads equal to or less than 100A continuously. For instantaneous overloads caused by inrush current from magnetic devices, or short circuit conditions, the automatic bypass shall be capable of sustaining overloads of 1000% of system capacity for sub cycle fault clearing.
F.Modular: The automatic bypass switch shall be of a modular design and easily field replaceable by certified technicians
2.8DISPLAY AND CONTROLS
A.Control Logic: The UPS shall be controlled by two fully redundant,
B.Display Unit: A microprocessor controlled display unit shall be located on a hinged door in the front of the system. The display shall consist of an alphanumeric display with backlight, an alarm LED, and a keypad consisting of pushbutton switches.
CSI SECTION 16611 STATIC UNINTERRUPTIBLE SYSTEM