Megger TTR20 Specifications
TTR™20-1
Handheld TTR
TTR™20-1
Handheld TTR
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Simple, one-button operation
n
Lightweight, handheld
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Battery powered (AA or LR-6)
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Tests turns ratio, excitation current,
and polarity
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Ability to record via optional printer
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Rugged metal connectors on leads and
unit
DESCRIPTION
The Megger TTR20-1 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.
The unique design of the TTR20-1 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 TTR20-1
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).
Its design makes this instrument well suited for use in a
variety of harsh environments. The TTR20-1 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. 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 TTR20-1 needs no additional software and
comes ready to use complete out of the box.
APPLICATIONS
The proper operation of a transformer relies almost entirely
on the electrical properties of its windings. To ensure
continued proper operation, transformers are tested to verify
that their electrical properties have not changed from design
specifications. A TTR is an extremely useful instrument for
testing transformer windings because it can help locate
several types of problems within single- and three-phase
transformers. This type of TTR is best suited for power
transformers up to 1 MVA.
It it used to determine the no-load accuracy of CTs and
PTs and also determine the need to further test faulty CTs
and PTs. The TTR20-1 applies voltage to the high-voltage
winding of a transformer and accurately measures the
resulting voltage from the low voltage winding. The ratio of
voltages is directly proportional to turns ratio. In addition,
the unit measures excitation current and polarity.
Transformer Turns Ratio
A transformer turns ratio test set such as the TTR20-1 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 nameplate ratio, it
may have a fault, which reflects in inefficient or improper
operation. To measure small ratio changes such as this, the
accuracy of a Megger TTR20-1 is needed.
TTR™20-1
Handheld TTR
Transformer Polarity
Polarity of a distribution transformer becomes of interest in
order to determine its proper connection within a power
network. The Megger TTR20-1 will identify normal (in phase)
and reverse polarity of the single-phase transformers.
FEATURES AND BENEFITS
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Fast, easy hand-held operation which allows testing in half
the time of other units.
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Powered by six standard “AA” alkaline batteries;
no charger needed. Provides up to 12 hours of field
operation.
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Measures turns ratio range of 10,000:1, with a high
accuracy (±0.2%, 0.8 to 4000) at a low excitation voltage.
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Records ratio and phase errors for bushing CTs to an
accuracy of ±0.2% nameplate. This reduces the need for
heavy test equipment and improves test time.
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Perfect for meter shops, the TTR20-1 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.
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Rugged metal connectors
make the TTR20-1 durable
even in the harshest
conditions.
Turns Ratio Accuracy*
±0.20% (0.8 to 4,000)
±0.25% (4,001 to 10,000)
*For Excitation Current Values no greater than preset value.
Display Full Graphics
LCD module, adjustable back-lighting, wide temperature range, 128
x 64 dots (21 characters by 8 lines)
Safety/EMC/Vibration
Meets the requirements of IEC-1010-1, CE and ASTM D999.75
Temperature Range
Operating: -20º C to 55º C (-5º F to 130º F)
Storage: -50º C to 60º C (-55º F to 140º F)
Relative Humidity
Operating: 0 to 90% noncondensing
Storage: 0 to 95% noncondensing
Protective Devices
High voltage side shorting relay, transient voltage suppressors and
gas surge voltage protectors
Measuring Time
Less than 5 seconds
Measurement Method
ANSI/IEEE C57.12.90 and IEC 600076.1 (2000)
Dimensions
240 H x 115 W x 50 D mm (9.5 H x 4.5 W x 1.9 D in.)
Weight
Approximately 1.3 kg (2.8 lb), including leads
Leads shown with rugged
metal connectors for durability
SPECIFICATIONS
Type of Power
Six standard “AA” (IEC LR-6) alkaline batteries
Battery Life
Up to 12 hours of field operation
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
Test Frequency
55 Hz internally generated providing a universal 50/60 Hz
test set
Excitation Current Range
0 to 100 mA, 4-digit resolution
Turns Ratio Range
0.8 to 10,000, 5 digit resolution
Transformer Polarity
Normal or reversed
Current (rms) Accuracy
±5% rdg ±0.5 mA
SALES OFFICE
Megger
4271 Bronze Way
Dallas, TX 75237 USA
T 800-723-2861
E sales@megger.com
TTR20-1--DS--US--V01
www.megger.com
ISO 9001:2008
The word ‘Megger’ is a registered trademark
Note: TTR25-1 and legacy model TTR25
differ only by metal connectors on
TTR25-1 and leads of TTR25-1. They are
not interchangeable.
ORDERING INFORMATION
Item (Qty) Cat. No.
Hand-held TTR20-1 TTR20-1
Included Accessories
Combined test leads, “X/H” winding, 1.8 m (6 ft) 2007-713-6
Instruction manual AVTMTTR20
Optional Accessories
Combined test leads, “X/H” winding, 3.6 m (12 ft) 2007-713-12
Combined test leads, “X/H” winding, 6 m (20 ft) 2007-713-20
Combined test leads, “X/H” winding, 10 m (33 ft) 2007-713-33
Printer package including battery/line power
serial thermal printer with paper, battery pack
and charger, printer interface cable, 120V, 60Hz 35755-1
Semi-hard fabric transport case 35788
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