APC 6739380EN/JC user manual Alarms, Maintenance bypass

Alarms

The autodiagnostic system considers any system status other than normal as a problem.

Prior to any other action, note any lights (A to N) on the hidden control panel that may be on.

Also note any messages on the screen.

Certain problems may result in the control panel not functioning.

In this case, it is strongly recommended to call the after-sales support department.

◗if the load is still correctly supplied with power, it has probably been transferred to Mains 2 (static switch) and is therefore no longer protected;

◗if the load is no longer supplied with power, transfer it manually to the maintenance bypass (see section below).

Maintenance bypass

This operation is possible only if the system includes a Mains 2. It results in the load being directly supplied by Mains 2 via maintenance bypass switch Q3BP, thus ensuring a higher level of security in the event of a malfunction.

Important:

Prior to beginning the bypass operation, shut down all system inverters (press the "inverter off" button

7on each UPS control panel). If an inverter remains operating and the Mains 2 transfer conditions are not correct, the load will suffer a 0.8 second interruption.

Switching procedures are explained on a drawing next to each switch. It is imperative that the operation proceed in the following order:

◗shut down any inverters that may still be running;

!	!	+ –	I	O
			7

◗1 : close maintenance bypass switch

Q3BP;
◗ 2 : open inverter output switch Q5N;
◗ 3 : open Mains 2 input switch Q4S:
	bypass
	Q1	Q4S		Q3BP		Q5N
1	ON		ON	OFF	ON		ON
	(I)		(I)	(0)	(I)		(I)
2	ON		ON	ON		ON OFF
	(I)		(I)	(I)		(I)	(0)
3	ON	ON OFF		ON		OFF
	(I)	(I)	(0)	(I)			(0)

Note:

◗in systems with a Static Switch Cubicle, the above operation is carried out in the Static Switch Cubicle;

◗the operation with the three switches is carried out in reverse order (3, 2, 1) to return to normal status;

◗in an installation comprising modular UPSs with an external maintenance bypass, the operation is carried out in the external maintenance bypass. The cubicle is not equipped with a Q4S switch and it is therefore necessary to open the protection devices upstream on the maintenance-bypass line.

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