Toshiba 1500 Operation Modes AC Input Mode normal operation, Power flow in AC input mode

TOSHIBA

5.0Operating the UPS

5.1 Operation Modes

5.1.1 AC Input Mode (normal operation)

Power

input plug

Fuse

Bypass circuit

UPS

receptacles (rear panel)

UPS main circuit

5-15P	Transformer
	(Plus Series)	5-15R

UPS batteries	+	= power flow
	-

Power flow in AC input mode

The above illustration shows circuit power flow in the ac input mode. The UPS unit's rectifier, included in a boost chopper circuit, converts ac input power to dc power. This dc power runs the unit's transistor inverter and charges the batteries. The boost chopper circuit maintains a constant voltage, with current limiting, for charging the batteries and assures proper sine waveform generation for the output current. The unit's batteries are maintained in a constantly charged state when the UPS is in the normal operation mode. On the front panel, LED's labeled "On Line" and "AC Input" should be on and the "Fault" LED should be off

(See Section 9.2 Panel Layout).

5.1.2Battery Backup Mode

Power

input plug

Fuse

Bypass circuit	UPS
	receptacles
	(rear panel)

UPS main circuit

5-15P	Transformer
	(Plus Series)

5-15R

+

UPS batteries

-

= power flow

Power flow in battery backup mode

The above illustration shows circuit power flow in battery backup mode. When commercial ac power failures occur, the UPS's batteries instantly begin supplying dc voltage to the UPS's main inverter circuit. This circuit changes (inverts) the dc power into ac power. The ac power is available at the unit's output receptacles. This back-up process will continue until the UPS's battery voltage drops below a specific minimum level. When this occurs, the batteries will stop supplying power to the load. This minimum level is the rated minimum voltage (Vmin). The rated battery voltage chart in section 5.6 (See Section 5.7 for battery backup time) shows (Vmin). On the front panel, LED's labeled “AC Input” and “Fault” should be off. The “On Line” and “Backup” LED’s should be on (See Section 9.2 Panel Layout).

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