GE AMX-II

GENERAL ELECTRIC MEDICAL SYSTEMS AMX-il X-RAY UNIT
7-1576 SM A0654E
SEC. 1 FUNCTIONAL DESCRIPTION
NOTE: Waveform (Ex: W31-A) will be found in Sec. 11 of this chapter.
The АМХ-П is a battery powered X-ray unit rated to provide up to 110 kvp at 100 ma (fixed ma) for
radiography. The unit cannot be operated with the charge cord piugged into a wali outiet. Power is ob-
tained from the batteries for the collimator lamp, motor drive and X-ray exposures. If fully charged the
batteries will provide up to 10,000 mas at 100 kvp for X-ray exposures provided the rotor on-time is
limited to 10 seconds per exposure.
Refer to the simplified block diagram of the AMX-II in Illustration 6-1. The battery charger is energized
when the charge cord is inserted into a suitable wall outlet. Incoming AC power is rectified and fed to
the battery. The battery charger includes a circuit to sense the battery charge level and automatically
turn off the charger when the battery voltage reaches a predetermined level.
Battery power is connected to the 60 Hz and 500 Hz inverter drivers and the 60 Hz and 500 Hz inverter
circuits. Both inverters change the DC battery power into 60 Hz and 500 Hz. square wave power to per-
mit circuit isolation and transformation to higher and lower voltages.
The output of the 60 Hz inverter is fed to an isolation transformer. One secondary of this transformer
supplies power to the X-ray tube stator. Another secondary winding provides power to a transformer which
steps voltage down to supply the X-ray tube filament.
The 509 Hz inverter output feeds on autotransformer which is controlled by the knob on the kvp selector.
The autotransformer feeds the primary of the HV Transformer where it is stepped up and applied to the
X-ray tube during an exposure.
SEC.2 BATTERY CHARGER
Schematic reference sheet 1, Chapter 7.
The battery charger (a) provides pulsating DC voitage at about 140 V to the battery, (b) turns off the
charging voltage when the battery reaches 130 V, (c) energizes signal lamps to indicate “charge on” and
“charge complete”, and (d) actuates meter to indicate battery charge.
Refer to Illustration 6-2. When the line cord is inserted into a power outlet, AC voltage is supplied to
the bridge rectifier. If battery voltage is below 128 V as measured by the battery level sensor, the charger
will supply current to the battery. The battery level sensor also activates the ‘‘Charge On” indicator to
show that the battery is being charged. When battery voltage reaches 130, the battery level sensor will
turn off the charger and “Charge On” indicator, and activates the “Charge Complete” lamp.
2-1 Turning On Battery Charger
Schematic reference, sheet 1, Chapter 7.
When battery voltage drops below 128 V the bias voltage to the level sensor 4A107 (8,C) will cause it
to turn off (see W-41B). The bias voltage resulting across 4A1R9 will cause 4A1010 to turn off and de-
energize 4A1K23 (7,D). This opens contact 4A1K23-B (5,E) and places the gate of control SCR 4CR3 (5,A)
at a positive potential with respect to the cathode (see W-42) turning it on. Contro! SCR 4SCR 4CR3 will
charge the battery until it is turned off as described in Sec. 2-2.
6-1