Toshiba 4200FA CT/XT user manual Bypass Mode, Power flow in Bypass mode

TOSHIBA

6.2Bypass Mode

If the UPS unit is severely overloaded or develops an internal fault, power flow is automatically switched from the main circuit to the Bypass circuit. Power flow through the bypass is shown in the following illustration. This changeover occurs automatically in less than 4 milliseconds in phase (Make-Before-Break). If the power flow is transferred to the Bypass circuit because of an overload and that overload condition ends within a specified period of time, then the power flow will "re- transfer" to the AC Input Mode (Normal Operation) automatically. If the power flow is transferred to the Bypass circuit due to a fault condition, then the power flow must be transferred manually from the UPS's Bypass circuit back to the Inverter circuit after repairing the fault (see "Start-up Procedure"). If the power flow is transferred to the Bypass circuit due to an overload condition, then the power flow will automatically transfer from the UPS's Bypass circuit back to the Inverter circuit after removing the overload (see "Overload Operation").

Power Flow

Input

Power

Isolating

XFMR

MCCB

Converter

MBS

Bypass

Inverter

Charger/

Chopper

Output Power

External

Batteries

Power flow in Bypass mode

6.3Bypass Mode for Optional Alternate Input Models

Power Flow

Bypass

Power

Input	Isolating
Power	XFMR

MCCB

Converter

MBS

Bypass

Inverter

Output Power

Charger/

Chopper

External

Batteries

Power flow in Bypass mode for the Alternate Input Models

4200FA CT/XT User’s Manual 38