Specifications

E–14 Principles of Operation
The Magnetic Pick–up Unit (MPU)
The magnetic pick–up unit (MPU) is mounted next to the shuttle motor
flywheel. It provides timing information to the hammer fire controller by way
of the CCB. The rotation of the flywheel generates a pulse signal in the
MPU. The output frequency is 100 times the shaft frequency of the shuttle
motor. The MPU pulse train has one missing pulse in every revolution of the
motor for indexing. The incoming signal from the MPU is processed with a
zero–crossing detecting circuit to produce a clean signal, compatible with
system logic. The clean signal is then sent directly to the CCB.
Power Supply PCBA
The printer power supply is contained on a printed circuit board assembly
(PCBA) mounted in the card cage. It senses and adjusts to any commercial
electrical system that provides ac mains potential in 50 or 60 Hertz systems.
AC input power is converted to dc power and sent to the mechanism driver
board for distribution to logic and electromechanical circuits.
AC Power
The power supply operates on ac voltages ranging from 86 to 264 V. It can
tolerate variations in frequency of 47 or 63 Hz. The power supply is designed
to withstand an ac input overvoltage of 300 Vac for one second with no
degradation of dc output voltage or damage to printer circuits.
DC Power
The power supply PCBA contains two dc power supply systems for the
printer. The first is a + 5 V bus for logic. The second consists of + 48 V and
+ 9.5 V buses for the electromechanical sections of the printer (that is, all
drive motors and the hammer bank).
The maximum total continuous average DC load is 346 W. The + 5 V supply
has a separate return line. Both returns are tied together in a single–point
ground.
There is an opto–isolated logic level input from the printer that can shut
down and latch off the + 48 V and + 9.5 V supplies while maintaining the
+ 5 V output. The return for this signal is the + 5 V return. In addition, this
shutdown circuit discharges and latches the + 48 V down to a level lower