ETI PI-800 Instruction Manual page 7

Electrical Test Instruments PI-800 and PI-1600
Section I - General Information and Specifications
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The vernier uses a simple knob to adjust the output manually within the range
determined by the coarse tap. Clockwise rotation always increases output,
which reduces confusion.
A convenient rotary switch selects the coarse tap. It activates relays in either the
PI-800 or PI-Aux to provide 7 ranges of output for the PI-1600 combined unit.
The indicator/control panel features:
(1) An Input Voltage indicator, which lights whenever power is connected to
the test set
(2) A green Control Power ON switch/indicator, which also turns on the main
output power
(3) An amber Output ON indicator, which lights when output is initiated.
(4) A red Interlock Indicator, which lights if control power is off, or if an inter-
lock open condition exists. It also functions as an output shut-down
switch, which turns off main power.
(5) Three System Status LEDs, which provide information on the internal
temperature of the buswork, as well as duty cycle limitations of the ver-
nier.
(6) Three Output LEDs, which show overcurrent usage of the test set, from 1x
to 10x.
(7) A Bus Overtemperature indicator on the rear, which lights if any bus con-
nection overheats.
Primary catastrophic overload protection for the test set is accomplished with
input fuses having high interrupting current capacity. Overload of the output
system is sensed by means of a Programmable Overload Detector (POD) on the
vernier autotransformer. The POD allows full utilization of the overload capabil-
ity of the test set, and eliminates costly and cumbersome fuse replacement re-
quired in other test sets. It senses actual temperature of the output bus, as well
as duty cycle overload use of the vernier, and provides visual indication by
means of green, yellow, and red LEDs. It will shut down the test set output if
extreme overloads or overtemperatures are detected, and will inhibit re-initia-
tion until there has been sufficient cooling time.
The output of the test set is controlled by means of a proven SCR controller. This
provides precise initial phase angle control to reduce DC offset for inductive
loads and more consistent pulse currents.
The measurement of output current and time is accomplished by means of the
proven MAC-21, which uses highly accurate A/D circuitry and intelligent firm-
ware to resolve true-RMS values of distorted waveforms. It also provides features
such as preset ON times for convenient jogging of output current without over-
heating the breaker or causing unwanted trips.
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