TTR™25
Handheld TTR
TTR™25
Handheld TTR
I Fully automatic; fast; easy-to-use;
robust; lightweight
I Battery powered
I Tests turns ratio, excitation current,
and polarity
I Simple, one-button operation
I Quick-start guide on front panel
I Operator-selectable languages
DESCRIPTION to verify that their electrical properties have not changed
The Megger TTR25 is an automatic hand-held battery from design specifications. A TTR is an extremely useful
operated transformer turns ratio test set. It is used to instrument for testing transformer windings because it can
measure the turns ratio, excitation current and polarity of help locate several types of problems within single- and
windings in single- and three-phase distribution and power three-phase transformers.
transformers (tested phase by phase), potential & current
It it used to determine the no-load accuracy of CTs and
transformers, and tapped transformers.
PTs and also determine the need to further test faulty CTs
The unique design of the TTR25 allows the user to operate and PTs. The TTR25 applies voltage to the high-voltage
the test set while holding it in one hand. It effectively winding of a transformer and accurately measures the
eliminates the user from having to kneel or bend down to resulting voltage from the low voltage winding. The ratio
operate the instrument and speeds up testing time. of voltages is directly proportional to turns ratio. In
Realizing the extreme environments in which the TTR25 addition, the unit measures excitation current and polarity.
must 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). Transformer Turns Ratio
A Transformer Turns Ratio Test Set such as the TTR25 can
Its design makes this instrument well suited for use in a directly measure the turns ratio of single-phase
variety of harsh environments. The TTR25 is particularly transformers as well as three-phase transformers.
suited for testing in substations, transformer-manufacturing Deviations in these measurements will quickly indicate
environments, and meter shops. It features a high-contrast, problems in transformer windings and in the magnetic
backlit LCD screen which can be seen in bright or ambient core circuits. Transformer ratio can change due to several
light. factors, including physical damage from faults, deteriorated
This unit measures a high turns ratio of 20,000:1 accurately insulation, contamination and shipping damage. If a
with the lowest excitation voltage. The excellent transformer ratio deviates more than 0.5 percent from the
repeatability of the TTR25 helps the users to determine the rated voltage ratio, it may not operate reliably. To measure
condition of transformers under test. It is designed for small ratio changes such as this, the accuracy of a Megger
simple, one button operation with the measured results TTR25 is needed.
displayed directly on the easy to read LCD or printed to Transformer Polarity
the optional printer. The TTR25 needs no additional
Polarity of a distribution transformer becomes of interest in
software and comes ready to use complete out of the box.
order to determine its proper connection within a power
network. The Megger TTR25 will identify normal (in
APPLICATIONS phase) and reverse polarity of the single-phase
The proper operation of a transformer relies almost transformers.
entirely on the electrical properties of its windings. To
ensure continued proper operation, transformers are tested
TTR™25
Handheld TTR
FEATURES AND BENEFITS Display full graphics
I Fast, easy hand-held operation. No need to kneel or LCD module, adjustable back-lighting, wide temperature range,
bend down to operate the instrument. 128 x 64 dots (21 characters by 8 lines)
I Powered by six standard “AA” alkaline batteries; no Transformer Winding Phase Relationship
ANSI C57.12.70-1978
charger needed. Provides up to 12 hours of field
CEI/IEC 76-1:1993 and Publication 616:1978
operation. AS-2374, Part 4-1982 (Australian Standard)
I Measures turns ratio range of 20,000:1, with a high Safety/EMC/Vibration
accuracy (±0.1%, 0.8 to 2000) at a low excitation voltage. Meets the requirements of IEC-1010-1, CE and ASTM D999.75
I Records ratio errors for bushing CTs to an accuracy of Temperature Range
±0.1% nameplate. This reduces the need for additional Operating: -20º C to 55º C (-5º F to 130º F)
test equipment and improves set-up time. Storage: -50º C to 60º C (-55º F to 140º F)
I Perfect for meter shops, the TTR25 can be used for Relative humidity
inspection purposes to determine the no-load accuracy Operating: 0 to 90% noncondensing
of most CTs and PTs. It also can be used to determine Storage: 0 to 95% noncondensing
the need to test potentially faulty CTs and PTs. Protective Devices
High voltage side shorting relay, transient voltage suppressors and
I Automatic self-calibration for each test.
gas surge voltage protectors
I User selectable languages: English, Spanish, German, Measuring Time
French and Portguese. Less than 5 seconds
Measurement Method
SPECIFICATIONS ANSI/IEEE C57.12.90
Type of Power Dimensions
Six standard “AA” (IEC LR-6) alkaline batteries 240 H x 115 W x 50 D mm (9.5 H x 4.5 W x 1.9 D in.)
Battery Life Weight
12 hours of field operation Approximately 1.3 kg (2.8 lb), including leads
Excitation Voltage
8 V rms for testing distribution or power transformers and PTs;
0.5, 1.5, or 8 V ac rms for testing CTs.
The excitation voltage is switched automatically if excitation
ORDERING INFORMATION
current exceeds a preset value. Item (Qty) Cat. No.
Test Frequency Hand-held TTR25 TTR25
55 Hz internally generated providing a universal 50/60 Hz test set
Included Accessories
Excitation Current Range Combined test leads, "X/H" winding, 1.8 m (6 ft) 35938
0 to 100 mA, 4-digit resolution
Instruction manual AVTMTTR25
Turns Ratio Range Electronic documents AVTDTTR25
0.8 to 20,000, 5 digit resolution
Optional Accessories
Transformer Polarity
Combined test leads, "X/H" winding, 3.6 m (12 ft) 35942
Normal or reversed
Combined test leads, “X/H” winding, 6 m (20 ft) 36013
Current (rms) accuracy
Combined test leads, “X/H” winding, 10 m (33 ft) 36042
(2% of reading + 1 digit)
Printer package including battery/line power
Turns Ratio Accuracy serial thermal printer with paper, battery pack
0.1% (0.8 to 2000) and charger, printer interface cable, 120V, 60Hz 35755-1
0.15% (2001 to 4000)
Printer package including battery/line power
0.25% (4001 to 10,000)
serial thermal printer with paper, battery pack
0.5% (10,001 to 20,000)
and charger, printer interface cable, 230V, 50Hz 35755-2
Semi-hard fabric transport case 35788
Quick-guide overlay in Spanish, French,
German and Portuguese 35945
UK UNITED STATES OTHER TECHNICAL SALES OFFICES ISO STATEMENT
Archcliffe Road, Dover 4271 Bronze Way Norristown USA, Toronto CANADA, Registered to ISO 9001:2000 Reg no. Q 09250
CT17 9EN England Dallas, TX 75237-1019 USA Mumbai INDIA, Trappes FRANCE,
Registered to ISO 14001 Reg no. EMS 61597
T (0) 1 304 502101 T 1 800 723 2861 Sydney AUSTRALIA, Madrid SPAIN
F (0) 1 304 207342 T 1 214 333 3201 and The Kingdom of BAHRAIN. TTR25_DS_EN_V04
F 1 214 331 7399 www.megger.com
Megger is a registered trademark
