Electrical Test Instruments PI-2500-G2 & PI-5000-G2
Section II - Detailed Description
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Page II-5
PI-5000 connection:
PI-2500 Indicator Control Panel Circuitry
The power for the control panel is provided by the INV/2 circuit, which is the
main input voltage divided by 2. This voltage, ranging from 104 VAC to 240 VAC,
powers a wide range switching power supply, which supplies 12 VDC to the rest
of the circuitry. When the CTL ON switch S1 is pressed, DS1 lights and relay K4 is
energized, and latches on if voltage interlocks are OK and the external control
relay energizes. K4 also provides 12 VDC power to the PC board, which has cir-
cuitry for Vernier position display and adjustment, tap selection and display, and
temperature readings. Pressing S2 turns control power off.
If any external interlock is open, as sensed by K1, indicator DS4 will light. Other-
wise, K2 will energize, which energizes K2 and allow operation of S3. When MAIN
ON switch S3 is pressed, relay K3 energizes, MAIN READY lamp DS3 lights, and
power is provided to external main contactor. If it operates, K3 is latched on
through its auxiliary contact.
If the output of the test set is ON, 12 VDC will be applied to DS5, and also will be
sensed by the PC board, which will inhibit tap change.
The INV/4A and B signals provide a voltage equal to ¼ the input voltage. This is
