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