Megger 550005B Specifications
Single-phase, Hand-cranked TTR
Transformer Turns Ratio Test Set
®
Single-phase, Hand-cranked TTR
Transformer Turns Ratio Test Set
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Used for testing single phase power and
distribution transformers
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Design based on precision bridge
measuring technique
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Unmatched accuracy (±0.1%) in a
portable design
®
DESCRIPTION
The Single-phase TTR® Transformer Turns Ratio Test Set
measures the turns ratio and exciting current of windings
in power, potential and current transformers. Deviations
in turns ratio readings indicate problems in one or both
windings or the magnetic core circuit.
The TTR test set aids in identifying:
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Shorted coils
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Open circuits
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Incorrect connections
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Internal faults or tap-changer defects in step regulators as
well as in transformers.
The single-phase, hand-cranked model measures highly
sensitive turns ratios of up to 129.99:1 with accuracy of
±0.1%. An optional auxilary transformer extends the ratio
range to 329.99:1.
The TTR set operates on the principle that the voltage ratio
of the transformer at no load is practically equal to the true
turns ratio.
The major source of error in a transformer is a primary
impedance drop due to magnetizing current, which is kept
to a minimum by excitation at a fraction of rated voltage.
By employing a design that meets both of these conditions
along with the use of a null balance system, the turns ratio
of a transformer can be determined accurately.
When measuring the turns ratio of distribution and power
transformers, the accuracy is well within 0.1%.
APPLICATIONS
The single phase model is primarily used for testing singlephase power and distribution transformers, for low-ratio
readings up to 129.99:1, or up to 329.99:1 with an auxiliary
transformer. It can be used to test three-phase transformers
by connecting and testing each phase separately.
FEATURES AND BENEFITS
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Provides unmatched accuracy (±0.1%) in a portable de-
sign.
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Packaged in a rugged, compact case.
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Measures highly sensitive turn ratios up to 129.99:1. An
optional auxiliary transformer extends this ratio range to
329.99:1.
SPECIFICATIONS
Output
8 V, 50/60 Hz
Metering
Four decade dials
Turns Ratio Range
0.001 to 129.999
Exciting Current
0 to 1 A (divide by 5 switch for increased resolution)
Accuracy
±0.1%
Dimensions
7.5 H x 14 W x 12 D in. (189 H x 353 W x 302 D mm)
Weight
16 lb (7.3 kg)
Single-phase, Hand-cranked TTR
Transformer Turns Ratio Test Set
®
OPTIONAL ACCESSORIES
Auxiliary Transformer
An auxiliary transformer extends the ratio range of singlephase models to 329.99:1. Turns ratio is 100:1 and 200:1,
and is accurate to within ±0.1%.
The auxiliary transformer includes all the necessary cables
for connection to the TTR set and the transformer under
test.
Dimensions
8 H x 13 W x 10 D in. (203 H x 330 W x 254 D mm)
Weight
13 lb (5.9 kg)
Calibration Reference Transformer
Calibration reference transformers are available for handcrank TTRs. They provide a reference standard for periodic
calibration checks to document proof of calibration.
A Calibration Certificate of turn ratio accuracy traceable
to the NIST is furnished with each calibration reference
transformer, providing accuracies of ±0.05%.
Dimensions
13 L x 9.25 W x 7 H in. (330 L x 235 W x 178 H mm)
Weight
19 lb (8.6 kg)
UK
Archcliffe Road, Dover
CT17 9EN England
T (0) 1 304 502101
F (0) 1 304 207342
UNITED STATES
4271 Bronze Way
Dallas, TX 75237-1019 USA
T 1 800 723 2861
T 1 214 333 3201
F 1 214 331 7399
ORDERING INFORMATION
Item (Qty) Cat. No.
Single-phase, Hand-cranked TTR 550005B
Included Accessories
Cable assembly 19494
With C-clamps for X (low-voltage) winding, 10 ft (3 m) [2]
With spring clips for H (high-voltage) winding,
13 ft (4 m) [2]
All cables are permanently connected to the test set.
Instruction manual AVTM55JD
Optional Accessories
Auxiliary transformer 550030
Calibration reference transformer 550050
OTHER TECHNICAL SALES OFFICES
Valley Forge USA, College Station
USA, Sydney AUSTRALIA, Täby
SWEDEN, Ontario CANADA, Trappes
FRANCE, Oberursel GERMANY, Aargau
SWITZERLAND, Kingdom of BAHRAIN,
Mumbai INDIA, Johannesburg SOUTH
AFRICA, and Chonburi THAILAND
ISO STATEMENT
Registered to ISO 9001:1994 Reg no. Q 09250
Registered to ISO 14001 Reg no. EMS 61597
SINGLEPH_TTR_DS_en_V13
www.megger.com
Megger is a registered trademark
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