Inverter shutdown or overload

Introduction (cont.)

See figure 13 for devices or installations operating in on-line mode with a bypass AC source.

3	5
1
2
A	B
1
D
	C
2

Fig. 13

If the conditions are not satisfied, the inverter will current limit to 165% 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 the overload curve in figure 14;

◗in all three of the above cases, inverter shutdown and supply of the load via the bypass AC source results in the following on the control panel:

◗light 4 goes off,

◗activation of the buzzer (continuous beep),

◗light 3 shines green,

◗the message "LOAD NOT PROTECTED, ON-LINE MODE" is displayed.

Parallel UPSs with redundancy

◗the shutdown of one UPS unit is of no consequence for the load. The others each take up an equal amount of load power and the load continues to be supplied normally;

Unit shutdown results in the following on the control panel:

◗ lights 4 and 5 go off,

◗activation of the buzzer (continuous beep),

◗the message "LOAD NOT PROTECTED, PARALLEL ON-LINE MODE" is displayed;

◗in the event of an overload, the system only loses its redundancy as long as the overload is less than the total rated power of the functioning units. If the overload is greater, the operating mode is that previously described for systems without redundancy.

Single-UPS unit (on-line or "ECO" mode)

◗ in the event of a UPS shutdown

(initiated by the user or by an internal

protective device), the load is

automatically transferred to the bypass

AC source. If transfer conditions are

satisfied, transfer takes place instantly,

without interruption to the load;

Note: transfer conditions are not

satisfied when bypass AC source

characteristics are outside tolerances

(voltage: ±10%; frequency as per

personalisation; phase sync with

inverter ±3°);

◗ in the event of a major transient

overload (greater than 1.65 In),

immediate transfer takes place as

above, without interruption to the load.

The return to the inverter is automatic

when the overload disappears if the

number of possible returns has not

been reached (0 to 255, programmable

by personalisation). If this number has

Parallel UPSs without redundancy

The shutdown of one inverter results in overload on the other inverters in operation. Two cases may then arise:

◗if the overload on each remaining inverter is > than 1.65 ln, the load is immediately transferred to the bypass AC source;

◗if the overload is less than 1.65 ln, the remaining inverters support the overload (see curve in figure 14), and the load is transferred to the bypass AC source;

◗after this transfer:

◗the light 4 goes off,

◗the buzzer is activated and sounds continuously,

◗the light 3 goes on and turns green,

◗the message "LOAD NOT PROTECTED, PARALLEL ON-LINE MODE" is displayed.

Frequency converters

◗in the event of a shutdown, the load is no longer supplied with power;

◗in the event of a major transient overload (greater than 1.65 In), the inverter will current limit to 165% of their rated current for 1 second before stopping;

◗in the event of a smaller but prolonged overload, the inverter respects the same overload curve as the single inverter and shuts down;

◗in all three of the above cases, inverter shutdown results in the following:

◗ lights 4 and 5 go off,

◗activation of the buzzer (continuous beep),

◗the message "LOAD NOT PROTECTED, ON-LINE MODE" is displayed.

been reached, the load continues to be

supplied by the bypass AC source. This

operating mode allows start-up of load

devices causing high inrush currents.

This system requires satisfied transfer

conditions.

	I
1,5	In
1,35	In
1,25	In
1,15	In
1,10	In
1,05	In
	In
	1	2	3	4	5	6	7	8	9	10	30	120	t (min)

Fig. 14

APC 20 - 200 KVA user manual Inverter shutdown or overload, Parallel UPSs with redundancy

Introduction (cont.)