User Manual Chapter 5 - Electrical Connections 25
5.2.3. The rectifier bridge and intermediate circuit
Mains power is rectified and filtered by capacitors. All models of PIX drives incorporate a precharge resistance diode bridge.
If over-voltage (OV signal) or under-voltage (UV signal) occurs in the intermediate circuit, no power can be drawn from it
because the inverter bridge locks.
During normal functioning, the DC voltage of the intermediate circuit U
DC
has a value equal to U
LN
* 2. If the motor is turned
by its load (as occurs during deceleration or braking), power flows into the intermediate circuit through the inverter bridge.
Voltage in the intermediate circuit therefore increases. The inverter bridge locks at a predetermined voltage, and the contacts
between terminals 1 and 3 open (provided the relay has been programmed as an alarm state signal). See section 6.15 for
details on resetting.
ULN
Optoisolamento
I/O regolazione
Microcontrollore
della regolazione
Res. Precarica
ULN
UDC
Figura 5.2.3.1 The rectifier bridge and intermediate circuit
The drive can be restarted automatically after an alarm condition. (See section 6.15 for further information on automatic
restarting.)
Locking can also be prevented by extending the deceleration ramp.
5.2.3. The inverter bridge
The inverter bridge features IGBT (Insulated Gate Bipolar Transistor) technology in all models of DVS drive. The inverter
bridge is protected by internal circuitry against over-voltage, over-current, short circuit between phases and short circuit to
ground. In the event a fault, the inverter bridge locks and the contacts between terminals 1 and 3 open (provided the relay has
been programmed as an alarm state signal). See section 6.15 for information on resetting.
The drive can be restarted automatically after an alarm condition. (See section 6.15 for further information on automatic
restarting.)
Table 5.2.4.1: Inverter bridge protection alarm signalling
Signal Lock caused by
OV Over-voltage
OC Over-current, short circuit between phases
OC Short circuit to ground
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