INTRODUCTION
AVTMTTR20 Rev 4 Dec 2015
3
A block diagram of TTR20 is shown in Figure 1-1. The excitation voltage
oscillator applies a 55-Hz test voltage to a transformer under test. There are
three test voltages: 0.5 V, 1.5 V, and 8 V used for transformer testing. Test
voltage selection is based on excitation current required. The required test
voltage is selected automatically.
Input and output transformer voltages are applied to conditioning circuitry. This
circuitry improves signal-to-noise ratio of the test signal, and provides full voltage
range of the test signals at A/D converter inputs.
A/D converter is used to convert the analog measurement signals to their digital
replica. The converted output digital signals are applied to CPLD (complex
programmable logic device) and then are transferred to microprocessor.
The microprocessor is the main part of the TTR test set. It provides proper timing
sequence of operation, gathers and calculates the test result, and interfaces with
peripherals. There are three main peripherals in the TTR20 test set:
RS-232/Printer port, LCD and keypad.
DC power supply converts the primary battery voltage, six Energizer
®
X91 AA-
alkaline batteries, 9 V (nominal), 3135 mAh nominal capacity, into the secondary
DC voltages required for proper operation of the TTR20 test set.
Summary of Contents for TTR20
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