Emerson MPR15 Series - Manual (Page 21)

21
25A Switch Mode Rectifier  NT5C06B / C Installation and User Manual
Operation
Rectifier operation
The main AC line voltage is rectified and filtered to an unregulated high DC
voltage. The input circuit provides EMI filtering, inrush current limiting, low
and high AC inhibition, lightning and surge voltage protection, and input
fault protection through an AC breaker.
The high frequency isolating power section consists of a full bridge
converter using power MOSFETs and a high frequency power
transformer.
The high frequency AC voltage generated at the secondary of the power
transformer is rectified and filtered. The output section provides EMI
filtering, a shunt for output DC current sense, and output protection in
the form of a DC breaker. A current mode pulse width regulator varies
the pulse width of the signal driving the power MOSFETs. This allows
regulation to the output DC voltage.
The monitoring circuitry includes soft start, rectifier fail alarm (RFA),
rectifier RFA/ON LED, local and remote equalize, temporary release,
thermal shutdown, AC valid, local and remote high voltage shut down
(HVSD), local and remote HVSD reset, logic valid, fan failure detection,
and a fan failure LED.
A three-digit output current meter reads the output shunt and displays
the value using an integrated logic circuit.
An auxiliary power supply provides the various voltages required by the
internal circuitry and cooling fan.