Free Service Manuals

                                    The Twin Stabilised D.C, Supply PP3 is a portable instrument
providing two independent and floating stabilised d.c.
supplies, each variable from 0 to 3ÖV at 1A maximum. The two
supplies can be used separately, or connected in series lo
provide a maximum output of 60V at 1A.

In both sections of the instrument, the range is covered in
three overlapping nominal 10V steps, with fine adjustment
provided by a variable control directly calibrated in volts.
A voltmeter and a dual-range ammeter are provided, and these
can be switched independently to monitor either section.

Both sections are provided with four terminal output
networks which virtually eliminate the effect of
resistance in the connecting leads to the load.

Overload protection is effected by an electronic circuit
which affords complete protection against both progressive
and sudden short circuit overloads. This circuit is reset
from the front panel by operation of the on/off switch.

The instrument will operate from a.c. supplies of 90 to 130V
and 200 to 240V. Fuses are provided to protect against both
supply surges and internal component failure. The Twin
Stabilised D.C. Supply PP3R is a 19-inch rack mounting
version of the PP3. The specification is identical to the
PP3 but the PP3R has the additional facility of the output
being available on a 10-way terminal block at the rear of
the instrument.

SECTION I	Introduction	3

SECTION 2	Specification	4

SECTION 3	Operating Instructions	5

3.1	Preparations for Use	5

3.2	Metering	5

3.3	Overload	5

3.4	Four Terminal Network	5

3.5	Fuses	5

SECTION 4
	Circuit Description	6

4.1	General	6

4.2	Stabilising Circuit	6

4.3	Overload Cut-out
	 
SECTION 5
	Maintenance	7

5.1	General	7

5.2	Realignment of Voltage Calibration 7

5.3	Adjustment of Overload Cut-out	7 

SECTION 6	Components List	9 

SECTION 7	Factory Service	10