Liebert Series 600T manual Momentary Overloads, Refer to 3.4 Automatic Operations

3.2.3Momentary Overloads

An overload in the critical load will continue to be supplied by the UPS system if the overload condition does not exceed the current versus time curve of overload capacity for either the SCC rating or for the number of modules on-line.

For momentary overloads exceeding 155% of rated system (SCC) current, the static switch turns on for 40 milli- seconds to provide current from the bypass line in parallel with current from the UPS system output. Up to 1000% of rated current can be supplied for less than one cycle, while up to 500% of rated load can be sustained for the full 40 milliseconds of pulsed-parallel operation. By providing two power sources simultaneously, high current can be supplied to the critical load with full output voltage regulation. The critical load can be supported through inrush currents and momentary faults without operating the motorized circuit breakers.

If an overload situation exceeds 40 milliseconds, the UPS system continues to supply power to the critical load if it remains within the current versus time curve of overload capacity. If the system overload capacity is exceeded, the UPS control logic at the SCC initiates an automatic transfer to the bypass line by operating the static bypass switch and the motorized system circuit breakers (SBB and UPS Output).

Refer to 3.4 - Automatic Operations.

Figure 50 Momentary Overload (Pulsed Static Bypass Switch)

		RIB			RIB			RIB		BFB
UPS #3			UPS #2			UPS		#1
CB1			CB1			CB1
								SBS
	R			R			R			BIB
									SBB
	I			I			I				MBB
CB2			CB2			CB2		System		SKRU
								Controls

Output MIB

					SCCT
	MBD				To Critical Load
			MBD		MBD
Battery					SCCT
		Battery		Battery
					(can accommodate up to 6 UPS modules)

Operation 81

DISCONTINUED

PRODUCT