- Single- and three-phase transformer testing
- Fast, easy hand-held operation.
- Powered by six standard “AA” alkaline batteries; no
charger needed.
- Provides up to 12 hours of field operation.
- Measures turns ratio range of 10,000:1, with a high
accuracy (±0.1%, 0.8 to 2000) at a low excitation voltage
- Records ratio errors for bushing CTs to an accuracy
of±0.1% nameplate. This reduces the need for additional test
equipment and improves set-up time.
- Perfect for meter shops, the TTR20 can be used for
inspection purposes to determine the no-load accuracy of most
CTs and PTs. It also can be used to determine the need to test
potentially faulty CTs and PTs.
- Automatic self-calibration for each test.
- Simple, one-button operation Quick-start guide on front
panel
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Megger TTR20 Shown
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The Megger TTR20 is an automatic hand-held battery operated
transformer turns ratio test set. It is used to measure the turns
ratio, excitation current and polarity of windings in single- and
three-phase distribution and power transformers (tested phase by
phase), potential & current transformers, and tapped transformers.
A Transformer Turns Ratio Test Set such as the TTR20 can directly
measure the turns ratio of single-phase transformers as well as
three-phase transformers. Deviations in these measurements will
quickly indicate problems in transformer windings and in the
magnetic core circuits. Transformer ratio can change due to several
factors, including physical damage from faults, deteriorated
insulation, contamination and shipping damage. If a transformer
ratio deviates more than 0.5 percent from the rated voltage ratio,
it may not operate reliably. To measure small ratio changes such as
this, the accuracy of a MeggerTTR20 is needed.
The unique design of the TTR20 allows the user to operate the test
set while holding it in one hand. It effectively eliminates the user
from having to kneel or bend down to operate the instrument and
speeds up testing time. Realizing the extreme environments in which
the TTR20must operate, special attention has been paid to making it
extra rugged, with a high impact, shock resistant case, yet
incredibly lightweight at a mere 870 g (1.9 lbs).
Its design makes this instrument well suited for use in a variety of
harsh environments. The TTR20 is particularly suited for testing in
substations, transformer-manufacturing environments, and meter
shops. It features a high-contrast, backlit LCD screen which can be
seen in bright or ambient light.
This unit measures a high turns ratio of 10,000:1 accurately with
the lowest excitation voltage. The excellent repeatability of the
TTR20 helps the users to determine the condition of transformers
under test. It is designed for simple, one button operation with the
measured results displayed directly on the easy to read LCD or
printed to the optional printer. The TTR20 needs no additional
software and comes ready to use complete out of the box. |
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Specifications |
Description |
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Excitation Voltage |
8 V rms for testing distribution or power transformers and PTs; |
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0.5, 1.5, or 8 V ac rms for testing CTs. |
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The excitation voltage is switched
automatically if excitation current exceeds a preset value. |
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Test Frequency |
55 Hz internally generated providing a universal 50/60 Hz test set |
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Excitation Current Range |
0 to 100 mA, 4-digit resolution |
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Turns Ratio Range |
0.8 to 10,000, 5 digit resolution |
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Transformer Polarity |
Normal or reversed |
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Current (rms) accuracy |
(2% of reading + 1 digit) |
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Excitation Voltage |
0.1% (0.8 to 2000) |
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0.15% (2001 to 4000) |
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0.25% (4001 to 10,000) |
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Display full graphics |
LCD module, adjustable back-lighting, wide temperature range,128 x 64 dots (21 characters by 8 lines) |
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Transformer Winding Phase Relationship |
ANSI C57.12.70-1978 |
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Safety/EMC/Vibration |
Meets the requirements of IEC-1010-1, CE and ASTM D999.75 |
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Temperature Range |
Operating: |
-20º C to 55º C (-5º F to 130º F) |
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Storage: |
50º C to 60º C (-55º F to 140º F) |
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Relative humidity |
Operating: |
0 to 90% non-condensing |
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Storage: |
0 to 95% non-condensing |
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Protective Devices |
High voltage side shorting relay, transient voltage suppressors andgas surge voltage protectors |
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Measuring Time |
Less than 5 seconds |
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Measurement Method |
ANSI/IEEE C57.12.90 |
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Type of Power |
Six standard “AA” (IECLR-6) alkaline batteries |
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Battery Life |
12 hours of field operation |
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Dimensions |
9.5(H) x 4.5(W) x 1.9(D) in. (240 x 115 x 50mm) |
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Weight |
Approximately 2.8 lb (1.3 kg) , including leads |
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