Emerson user manual Series 7400 UPS Isolator configurations

Series 7400 Single Phase 1+N UPS

	M a i n t e n a n c e B y p a s s
	Isolator	M a i n t e n a n c e B y p a s s L i n e
Bypass	Bypass Isolator
		Static Bypass Line
Supply
Mains			STATIC	UPS
	RECTIFIER	INVERTER		Output
Supply			SWITCH
				Supply
	I n p u t		O u t p u t
	I s o l a t o r	B a t t e r y	I s o l a t o r
		B r e a k e r

BATTERY

A. BLOCK SCHEMATIC FOR 230V OUTPUT 1PH. UPS SYSTEM

Bypass Supply

B y p a s s

Isolator

Mains

Supply

	M a i n t e n a n c e B y p a s s L i n e
		M a i n t e n a n c e B y p a s s
		Isolator
	Static Bypass Line
		STATIC	UPS
RECTIFIER	INVERTER		Output
		SWITCH
			Supply
Input		O u t p u t
Isolator		Isolator
	Battery
	B r e a k e r

BATTERY

B. BLOCK SCHEMATIC FOR 110V OUTPUT 1PH. UPS SYSTEM

Figure 2: Series 7400 UPS Isolator configurations

1.2.3Bypass Supplies The circuit block annotated ‘Static Switch’ in figure 2 contains an electronically controlled switching circuit, which enables the critical load to be connected either to the Inverter output or to a Bypass power source via the ‘static bypass line’. Normally, the load is connected to the inverter; but in the event of a UPS overload, or inverter failure, it is automatically transferred to the static bypass line due to static switch action. Note that the Bypass supply should be in normal condition and enabled.

To provide a clean (no-break) load transfer between the inverter output and static bypass line, the inverter output and bypass supply must be fully synchronised during normal operating conditions. This is achieved through the inverter control electronics which make the inverter frequency track that of the static bypass supply - provided that the bypass remains within an acceptable frequency window. The synchronising window is pre-selected to 2% of nominal frequency, giving an acceptable frequency window of ±1Hz.

Awarning message [INVERTER UNSYNCHRONIZED] is displayed on the operator control panel when the inverter and bypass supplies are not synchronized.

A second, manually controlled, ‘Maintenance bypass’ supply is also incorporated into the UPS design. Its purpose it to enable the critical load to be powered from the mains (bypass) supply while the UPS is shut down for maintenance or troubleshooting.

Note:- The load is unprotected against mains power supply aberrations or failure when it is connected to either the static bypass or maintenance bypass supply.

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