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18 Hardware description
Inverter power switch-off sequence
WARNING!
Do not open the DC switch-disconnector [Q11] while the inverters are loaded.
The terms and designations used in the table below refer to the diagrams in section
Connections of the DC supply
1. User stops the inverters.
2. User turns DC switch-disconnector [Q11] handle to position 0 (OFF).
•
DC switch-disconnector [Q11] disconnects inverter(s) from the DC power supply.
•
Contact 13-14 of DC switch-disconnector [Q11] switches off the AUX2 signal to the
BSFC unit. BSFC switches INV1 EN signal off, which disables inverter start.
•
Auxiliary contact 21-22 closes, energizing the solenoid of DC switch-disconnector
[Q11]. The solenoid releases the locking mechanism of the DC switch-disconnector.
Operation of the handle is possible as long as inverter DC voltage remains high.
•
INV UDC and PWR LEDs are on. The Charging OK light [P11] on the cabinet door
is on.
•
The inverter DC voltage decreases to zero gradually. When below 80% of nominal:
•
Inverters switch off UDC signals from BSFC unit.
•
BSFC switches off the operating voltage to solenoid of DC switch-disconnector
[Q11]. Locking mechanism activates, which prevents turning the handle into
position 1 (ON).
•
INV UDC and PWR LEDs are on.
Locking solenoid control
The DC switch-disconnector [Q11] has a locking solenoid, which prevents the operation of
the handle when the solenoid is de-energized. You can only close the DC switch-disconnector
[Q11] when:
•
DC voltage of all inverter modules monitored by the BSFC unit exceed 80% of the
nominal value. (BSFC receives U
•
DC switch-disconnector [Q11] handle is in position 0 (OFF).
circuit.
signals from inverters and energizes the solenoid).
DC
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