APC 9000 User Manual

34006452EN/AC

 - Page 12 

Introduction

Installation with an engine generator set 

(figure 15) 

   

 

UPS shutdown or overload 

(systems with a static switch module) 

(figure 16) 

Fig. 16

If a stand-by generator is included in the installation, it is generally started automatically in the event of a Mains failure and 
connected to the main low voltage switchboard. 

It is disconnected when Mains power is restored.

With such a system, the required battery  time may be reduced to the time necessary for starting and bringing on line the 
stand-by generator. 

The battery supplies power to the inverter during the transfers: Mains -

 

generator and generator -

 

Mains.

The transfer sequences described: Mains - battery

 

-

 

generator and generator

 

-

 

battery

 

- 

 

Mains are fully automatic. 

They in no way affect the load and require no manual operation by the user.

To avoid load surges on the generator, the rectifier/charger is started with a 10 second maximum current consumption walk-in.

– in the event of a UPS shutdown (initiated by the user or by an internal protective device), the load is automatically 

transferred to the Mains 2 bypass line. If transfer conditions are correct, transfer takes place instantly, without interruption to 

the load.

Note: 
Transfer conditions are not correct when Mains 2 characteristics are outside tolerances (voltage: ±10 %; frequency as per 

personalization; phase sync with inverter ±3°);

– in the event of a major transient overload (greater than 160 % of the full load), immediate transfer takes place as above, 
without interruption to the load.

When the overload disappears, the load is automatically returned to the inverter depending on the configured value of the

re-transfer counter: no return to inverter, or 1 to 255 (personalized value) overloads accepted before the load is permanently 
transferred to Mains 2. This operating mode allows start-up of load devices causing high inrush currents.

This system requires correct transfer conditions. If the conditions are not correct, the inverter will current limit to 150 % of its 

rated current for 1 second before stopping;

– in the event of a small but extended overload (i.e. a continuous level of power exceeding the full rated load), the inverter 
will continue to supply power for a period depending on the magnitude of the overload (10 minutes for a 125 % overload, 

1 minute for a 150 % overload). See figure 17 (Overload curve);

– in all three of the above cases, the inverter shutsdown and supplies the load via Mains 2 with the following information 
on the control panel:

– green "load protected" light

 off, 

– buzzer

on, 

– red "load not protected" light

 on.

mains 2

mains 1

G

main LV

switchboard

generator

HV

network

I

+ –

O

beep...beep...

mains 1

rectifier-

charger

battery

inverter

load

static switch

mains 2