Rockwell Automation SB3000 AC Power Modules - Manual (Page 70)

C-6 SB3000 Power Modules (Rittal)
C.3 SB3000 DC Bus Charging Sequence
The SB3000 pre-charge circuitry is controlled via a pre-charge contactor which is
under the control of the PMI Processor in the SB3000 PMI rack. Any faults relating to
pre-charge contactor operation are reported in registers 202/1202 and 205/1205. The
closing and opening of the pre-charge contactor is a function of the measured DC bus
voltage. See figure C.4.
Note that the RPI signal has no effect on the operation of the pre-charge contactor;
however, the RPI input must be present for the voltage loop to be in run. Turning off
the RPI signal does not disable output power. If AC input power is on, the diodes in the
IGBTs will conduct rectified voltage to the output terminals, independent of the state of
the RPI signal.
C.3.1 Pre-charge Contactor Requirements for SA3000/SA3100 Power
Modules
The status of the SB3000 pre-charge contactor (CHG_FB@) must be used by the
SA3000/SA3100 Power Module’s application tasks. The SA3000/SA3100 Power
Module must not operate with the pre-charge contactor open. Doing so may damage
the pre-charge resistor. It is the responsibility of the application tasks running in the
SA3000/SA3100 UDC module to make sure the SB3000 Power Module is in run
before the SB3000 Power Module is turned on.
If the SB3000 Power Module is shut down due to a fault condition, the controlled
shutdown of the SA3000/SA3100 Power Module is the responsibility of the
application.
Each SA3000/SA3100 Power Module must have its own pre-charge resistor and
contactor to limit the current into its capacitors.
C.3.2 Pre-charge Sequencing During Normal Operation
When AC power is applied to the SB3000 Power Module, the diodes in the IGBT
power devices allow the capacitors to begin charging immediately through the line
fuses, input inductors, and pre-charge resistors up to near peak AC line voltage. When
the DC bus has reached the close threshold voltage and is at a steady-state condition,
the PMI Processor will close the pre-charge contactor if there is no fault. After the
contactor is closed, the PMI Processor will turn on status bit CHG_FB@ to indicate
this condition to the application task. If there is a fault, the PMI Processor will turn on
the IC_FLT@ interlock to indicate that a fault needs to be reset.
!
ATTENTION: The UDC application task must examine the pre-charge
status bit (CHG_FB@) regularly. If the status bit turns off, the
SA3000/SA3100 Power Module must be shut down. If the
SA3000/SA3100 Power Module is not shut down, the pre-charge resistor
may be damaged. Failure to observe this precaution could result in to
damage to, or destruction of, the equipment.