MGE UPS Systems Galaxy PW user manual Inverter shutdown or overload, Parallel UPSs with redundancy

Galaxy PWTM 100 to 225 kVA

inverter shutdown or overload

See figure 9 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. 9

If the conditions are not satisfied, the inverter will current limit to 165% of its rated current for 1 second before stop- ping;

■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 over- load (10 minutes for a 125% overload, 1 minute for a 150% overload). See the overload curve in figure 10;

■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 PROTECT- ED, 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 sup- plied 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 PROTECT- ED, PARALLEL ON-LINE MODE" is dis- played;

■ 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 previ- ously described for systems without redundancy.

single-UPS unit (on-line mode)

■in the event of a UPS shutdown (initiat- ed by the user or by an internal protective device), the load is automatically trans- ferred 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%; fre- quency as per personalization; phase sync with inverter ±3°);

■in the event of a major transient over- load (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 num- ber of possible returns has not been reached (0 to 255, programmable by per- sonalization). If this number has 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.

parallel UPSs without redun- dancy

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

■if the overload on each remaining invert- er is > than 1.65 ln, the load is immediate- ly 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 con- tinuously,

❏ the light 3 goes on and turns green,

❏the message "LOAD NOT PROTECT- ED, PARALLEL ON-LINE MODE" is dis- played.

	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. 10

8 Introduction