APC 9000 User Manual

34006452EN/AC

- Page 38

Maintenance

Frequency converter or parallel UPS with SSC

(figure 28)

Note:

We recommend that you call on the after-sales support department to carry out these operations.

Static Switch Cubicle

(figure 29)

Note:
We recommend that you call on the after-sales support department to carry out these operations.

During maintenance, the concerned UPS or
converter must be isolated from Mains 1, its

battery and the output circuits of the other units.

– inverter isolation
Proceed in the following order:

– shut down the inverter (press the "inverter off"

button

for 3 seconds),

– open isolating switches Q5N, QF1 and Q1 for

that line.

The unit is powered down once the capacitors
have discharged (a few minutes).

In redundant systems with at least one redundant

UPS, the other UPSs (or converters) ensure
continuity of power to the load.

In non-redundant systems with a Mains 2, the

load is supplied by the Mains 2 and the Static
Switch Cubicle.

In non-redundant systems without a Mains 2, the

entire system must be shut down.
– start-up

Following servicing, proceed in the following

order:
– close switch Q1, then switches QF1, Q5N and

Q4S,

start the inverter (press the "inverter on"
button

Fig. 28: frequency converter exemple

During maintenance, the Static Switch Cubicle
must be isolated from Mains 2, the load and the

parallel UPSs.

– if work is required on the control electronics
alone, open cubicle switch Q4S (but not Q5N) and

cubicle fuse switches Q1 and Q2. The load can

then remain supplied by the UPSs. After
servicing, reclose fuse switches Q1, Q2 and

switch Q4S.

Caution:
When the Static Switch Cubicle is powered down

using the above procedure, only the control

electronics are in fact powered down. The power
circuits remain energized. Maintenance on the

static switch power circuits requires shutdown of

the UPSs and transfer of the load to the
maintenance bypass line.

– open switch Q5N, then the disconnector-fuses

Q1 and Q2 in the SSC;
– open switches Q5N, then switch Q4S on all the

UPSs (figure 29).

Caution:
Even in the maintenance bypass

configuration, the cubicle is only partially

shut down and the supply of power to the load
continues via switch Q3BP.

more extensive maintenance work on the Static

Switch Cubicle requires the entire system to be
shut down.

Fig. 29

mains 1

load

mains 1

QF1

Q5N

mains 1

load

mains 1

mains 2

QF1

Q5N

Q3BP

Q4S