ELECTRICAL SPECIFICATIONS



OUTPUT VOLTAGE:         0 to  3KV
OUTPUT POLARITY:        Reversible
OUTPUT CURRENT:         0 to 75mA
LINE REGULATION:        <  O.001%
LOAD REGULATION:        <  0.005%
RIPPLE:                 <  0.005%
STABILITY:              0.005%/hr.  0.01%/8 hours
TEMP.COEFFICIENT:       50 ppm/OC over range of 0 to 50'C
OUTPUT TERMINATION:     SHV Type 1707-1
INPUT VOLTAGE:          115V +/-10%  50/50 Hz.


VARIABLE OVERVOLTAGE PROTECTION (VOV):



A rear panel mounted single turn potentiometer
provides the capability of power supply shut-down
when the output voltage exceeds the setting of
this rear panel over-voltage potentiometer.

Maximum clockwise rotation of this potentiometer
will allow the power supply to operate at the
maximum output voltage rating of the power  supply.
This is a linear control.  Thus, a setting of 50%
of the maximum rotation of this potentiometer  will
result in power supply shut-down at one-half the
output voltage.

A more exact method of setting the over-voltage
trip point would be to use this rear panel  mounted
potentiometer control in conjunction with the front
panel meter and the front panel voltage control
potentiometer, thus achieving the desired over-
voltage shut-down setting.

A front panel LED indicates an over-voltage condition.

The power supply may be reset by turning the  power
supply off, using the front panel ONIOFF toggle switch.

After a 10 second interval turn the power supply back
on by using the same front panel ON/OFF toggle switch.


SPECIAL CIRCUITRY:



This unit incorporates circuitry which allows
the power supply to operate at its normal high
voltage output as set by the front panel controls
when the relay coil is not energized.

When the relay coil is energized the output voltage

drops to approximately 50% of its normally set value.

Remote control of the relay is achieved via J3, located
on the rear panel. (Amphenol 7-pin connector Type 126-198).
The relay will be energized when Pin D of J3 is +5V
with respect to Pin A of J3.
A front panel mounted LED labeled "RELAY ON" will be
illuminated when the relay is energized.


              VOLTAGE CONTROLS

The output voltage is controlled by the combined
settings of the step selector switch providing
steps of 0, 1KV and 2KV and a digital reading
10-turn potentiometer  which  provides  a  continuous
Vernier control from 0 to 1000 volts.  The setting
resolution is 2OOmV.

                  POLARITY

Gamma Model PR3-75R/m79  is  equipped  with  polarity
reversal capability.  The screw-driver operated
polarity reversal switch is located on the rear
panel of the power supply.  The setting of the
polarity switch is indicated by illumination of
either the Positive or Negative LED indicator on
the front panel.
CAUTION:   Line input power must be  turned  off  and
           the high voltage output should be discharged
           to ground at the output connector before
           reversing polarity.

            HIGH VOLTAGE OUTPUT

Dual high voltage output connectors are located on
the rear panel, Kings type SHV 1707-1.

                METERS

A front panel analog meter provides reading of
output voltage or current with an accuracy  of  +/-2%
full scale.

Voltage or current readings are selected with toggle
switch located adjacent to the meter.


                REMOTE MONITORING

 Remote voltage and current monitor signals are
 available at TB1 located at the rear of the power
 supply.

 VOLTAGE MONITORING:
      1)  Connect external volt meter between
          terminals 8 and 4 of TB1.
               Terminal 8:  Positive
               Terminal 4:  Negative
          SCALING FACTOR:   5V = 3KV

 CURRENT MONITORING:
      A voltage of 1 mV/mA is available between
      Terminals 11 and 12 of TB1.  This voltage
      is directly proportional to the output
      current.
               Terminal 11 is chassis ground.
               Terminal 12 is the current monitor point.


               EXTERNAL INTERLOCK

 Terminals 9 and 10 provide a convenient means of
 disabling the power supply from a remote location.

 Shorting terminals 9 and 10 will enable the power
 supply.

 An open circuit between terminals 9 and 10 will
 disable the power supply.


           REMOTE PROGRAMMING

VOLTAGE PROGRAMMING:

The high voltage output can be remotely programmed
from either an external voltage source or with an
external potentiometer from the internal  voltage
source.

A front panel REMOTE/LOCAL switch selects  either
remote programming or front panel control of  the
output voltage.  When this switch is in the REMOTE
position the front panel controls have no  effect
on the output voltage.

A 0 to -5V programming voltage applied to
terminals 2 and 4 of TB1 (Terminal 2: -5V,
Terminal 4:  Common), will remotely program the
high voltage output from 0 to maximum.

Programming can also be accomplished using a potentiometer
connected to Terminals 1, 2 and 4 of TB1.  The CW
terminal of the potentiometer should be connected to
Terminal 1 of TB1, the wiper to Terminal 2 of TB1,
and the CCW to Terminal 4 of TB1.

The potentiometer should be a low temperature coefficient
wire-wound or cermet type, 5 Kohm to 20 Kohm resistance
value.  The output is proportional to the programming
input.


     OVERLOAD AND SHORT CIRCUIT PROTECTION

 Full protection against any overload condition is inherent
 in the constant current/constant voltage design concept
 employed in this power supply.

 This is augmented by the liberal use of surge limiting
 resistors and reactive limiting.