Megger TTR20 Instruction Manual
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Megger TTR20 Instruction Manual

Transformer turn ratio test set
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Instruction Manual AVTMTTR20
Transformer Turn Ratio Test Set
Catalog Nos. TTR20 and TTR20-1
Read the entire manual before operating.
Antes de operar este producto lea este manual enteramente.
for
TTR20 Handheld TTR
(TTR20 DISCONTINUED)
High-Voltage Equipment
Aparato de Alto Voltaje
M
2621 Van Buren Ave
Norristown, PA 19403-2329
610-676-8500
www.megger.com
AVTMTTR20
Rev. 4
Dec 2015

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  • Page 1 Rev. 4 Dec 2015 Instruction Manual AVTMTTR20 TTR20 Handheld TTR Transformer Turn Ratio Test Set Catalog Nos. TTR20 and TTR20-1 (TTR20 DISCONTINUED) High-Voltage Equipment Read the entire manual before operating. Aparato de Alto Voltaje Antes de operar este producto lea este manual enteramente.
  • Page 3 TTR20 and TTR20-1 Handheld TTR Transformer Turn Ratio Test Set Instruction Manual...
  • Page 4 If the product or its individual instrument are used for purposes other than those specified herein, confirmation of their validity and suitability must be obtained from Megger. Refer to the warranty information included at the end of this instruction manual. Specifications are subject to change without notice.

  • Page 5: Table Of Contents

    About the TTR20 (TTR20-1) ..................1   Electrical Theory and Practice ................... 2   Applications for the TTR20 ..................4   Upon Receipt of the TTR20 ..................5   Safety First ......................... 5   How to Use This Manual .................... 5  ...
  • Page 6 TTR20 Functional Test .................... 28   Battery Replacement ....................29   Troubleshooting ....................... 30   Error Messages......................31   Repair ........................33   A - S ....................35 PPENDIX PECIFICATIONS   Electrical ........................35   Environmental Conditions ..................37  ...
  • Page 7 LIST OF ILLUSTRATIONS Figure 1-1. TTR20 Single-Phase Test Set Block Diagram ............. 4 Figure 3-1 TTR20 Display & Control Panel ................9 Figure 3-2 TTR20 Top Side Connector Panel ..............10 Figure 4-1 Setup for Testing Single-Phase Transformer ............. 13 Figure 4-2 Setup for Testing Single-Phase Autotransformer ..........

  • Page 9: Introduction

    Test Sets are fully automatic, self- checking, self-calibrating units. The TTR20-1 has metal lead connections versus plastic for the TTR20 (Replaced with the TTR20-1). This manual still refers to the TTR20 as a general model number, but for purposes of new instruments, only the TTR20-1 is currently sold.

  • Page 10: Electrical Theory And Practice

    Electrical Theory and Practice How the TTR20 Works The TTR20 test set provides the excitation voltage to the input of the transformer. It accurately measures both the H-side and X-side voltages to calculate turns ratio. The TTR also measures phase displacement (polarity) between primary and secondary windings of a transformer, and transformer excitation current.
  • Page 11 INTRODUCTION A block diagram of TTR20 is shown in Figure 1-1. The excitation voltage oscillator applies a 55-Hz test voltage to a transformer under test. There are three test voltages: 0.5 V, 1.5 V, and 8 V used for transformer testing. Test voltage selection is based on excitation current required.

  • Page 12: Applications For The Ttr20

    It is 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 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.

  • Page 13: Upon Receipt Of The Ttr20

    Notify Megger of any shortage. Telephone 610-676-8500. Examine the instrument for damage received in transit. If any damage is discovered, file a claim with the carrier at once and notify Megger or its nearest authorized sales representative, giving a detailed description of the damage.
  • Page 14 AVTMTTR20 Rev 4 Dec 2015...

  • Page 15: Safety

    Safety Requirements Megger has made formal safety reviews of the initial design and any subsequent changes. This procedure is followed for all new products and covers areas in addition to those included in applicable standards. Regardless of these efforts, it is not possible to eliminate all hazards from electrical test equipment.

  • Page 16: Cautions And Warnings

    Megger considers this an excellent safety practice. Users of equipment should note that high-voltage discharges and other sources of strong electric or magnetic field may interfere with the proper functioning of heart pacemakers.

  • Page 17: Controls & Connectors

    CONTROLS & CONNECTORS Overview The TTR20 is a simple, push-to-test instrument with few buttons and controls. It has no menus except for a print button. Contrast This knob adjusts the viewing resolution of the screen. Backlight A momentary depression of the switch will either activate or de-activate the backlight.

  • Page 18: Connectors

    Connectors TEST CABLE INPUT (Metal Connector for TTR20-1) PRINTER Figure 3-2 TTR20 Top Side Connector Panel TEST CABLE Plug receptacle for connecting test leads to the high-voltage (H) and low-voltage (X) windings of a transformer. The plug and receptacle are keyed...

  • Page 19: Setup, Connections And Operation

    Check that a lead set connected is labeled for TTR20 test set operation. The TTR20 has been designed to test a variety of transformers, such as: Single phase, Three phase (one phase at a time), CTs, PTs and Voltage Regulators.

  • Page 20: Single-Phase, Two-Winding Transformers

    The TTR20 may supply up to 100 mA of excitation current (4 digit resolution). The TTR20 will automatically select the appropriate test voltage (8 V, 1.5 V, or 0.5 V) when testing transformers. Single-Phase, Two-Winding Transformers Perform the following setup procedure for single-phase, two-winding transformers: 1.

  • Page 21: Figure 4-1 Setup For Testing Single-Phase Transformer

    X2 transformer terminal before starting the test. Expect that polarity of the windings is normal (“+” sign is displayed in front of the turns ratio test result). See Figure 4-7. H1 LEAD X1 LEAD TTR20 H2 LEAD X2 LEAD TRANSFORMER Figure 4-1 Setup for Testing Single-Phase Transformer...

  • Page 22: Figure 4-3 Setup For Testing Single-Phase, Type A Step Voltage Regulator

    X1 LEAD SERIES WINDING "RAISE" DIRECTION SOURCE H1 LEAD LOAD SHUNT WINDING TTR20 H2 LEAD COMMON Figure 4-3 Setup for Testing Single-Phase, Type A (Straight Design) Step Voltage Regulator X1 LEAD SERIES WINDING SOURCE H1 LEAD LOAD "RAISE" DIRECTION TTR20...

  • Page 23: Figure 4-5 Setup For Testing X1 - X2 Winding Of Distribution Transformer

    Figure 4-5 Setup for Testing X1 – X2 Winding of Distribution Transformer (H2 and X2 Grounded) H1 LEAD X2 LEAD TTR20 X1 LEAD H2 LEAD Figure 4-6 Setup for Testing X3 – X2 Winding of Distribution Transformer (H2 and X2 Grounded)

  • Page 24: Three-Phase, Two-Winding Transformers

    Three-Phase, Two-Winding Transformers Perform the following setup procedure for three-phase, two-winding transformers: 1. Connect the test cables to the test set. 2. Connect the clips marked H1 and H2 of the test lead to the phase being tested (high-voltage winding) terminals of the transformer under test. 3.
  • Page 25 X winding may result in damage to the CT. NOTES: The TTR20 may supply up to 100 mA of excitation current (4 digit resolution). The TTR20 will automatically select the appropriate test voltage (8 V, 1.5 V, or 0.5 V) when testing CTs. Some current transformers with turn ratio of 50:5 and less may require more than 100 mA of excitation current when excited from 0.5 V source.

  • Page 26: Figure 4-8 Setup For Testing Unmounted Current Transformer

    BUS OR USE HEAVY GAUGE LEAD WIRE X1 LEAD Figure 4-8 Setup for Testing Unmounted Current Transformer H1 LEAD X1 LEAD X1 LEAD TTR20 X1 LEAD TRANSFORMER Figure 4-9 Setup for Testing Taps on Multiple Tap CT AVTMTTR20 Rev 4 Dec 2015...

  • Page 27: Figure 4-10 Setup For Testing Bct Mounted On Single-Phase Two-Winding Transformer

    A turn-ratio test can be performed on a BCT after it has been mounted on a circuit breaker or power transformer entrance bushing. The test can be performed without removal of the BCT from the equipment. Connect the TTR20 to BCT as shown in Figure 4-10.

  • Page 28: General Operating Procedure

    Data shown on the menus and test screens in Figures 4-11 through 4-14 are for illustrative purposes only. The TTR20 test set menus and test screens are operated by using the keypad. On power up, the test set performs a self-test check, and all hardware and software variables are initialized.

  • Page 29: Figure 4-12 Start Test Screen

    If battery level is below 5%, the message “REPLACE BATTERY! UNIT WILL TURN OFF” appears on the screen. In 10 sec. the TTR20 shuts down. Replace the batteries (six AA-size replaceable alkaline batteries) before further attempting to initiate the TTR20 operation.

  • Page 30: Figure 4-13 Test In Progress Screen

    If during testing an abnormal condition is detected, one of the error messages listed in the ERROR MESSAGES section is displayed on the screen. In case of emergency, press the red button on keypad. It will turn TTR20 OFF. After emergency situation is gone, turn power ON (green button) to start TTR20 operation.

  • Page 31: Use With The Optional Printer

    If you are using the optional printer, plug the printer cable supplied into the RS232/PRINTER receptacle on the TTR20 test set and turn it on. A separate manual is supplied with the printer. Refer to it for specific information about how to connect, operate, and care for the printer.

  • Page 32: Figure 4-16 Printer Configuration Printout

    Configuration To print a paper copy of the existing printer settings: While holding down the "On-Line" switch, turn on the printer. The following list will print (factory default settings shown). Figure 4-16 Printer Configuration Printout AVTMTTR20 Rev 4 Dec 2015...

  • Page 33: Hyperterminal Configuration

    Setup, Connections & Operation If you want to leave the settings as they are, press the "FEED" switch. If you need to change a setting, press the "ON LINE" switch to enter the reconfiguration mode. For each group of switches, press the "FEED" switch if all the settings are okay.
  • Page 34 AVTMTTR20 Rev 4 Dec 2015...

  • Page 35: Maintenance And Troubleshooting

    As a result of such calibration procedure, each TTR20 may be NIST certified. To check the TTR20 calibration at a customer site or in the field, the Megger Calibration Standard Cat. No. 550055 or equivalent standard should be used. To perform a quick simplified calibration check, the Megger Calibration Standard Cat.

  • Page 36: Ttr20 Functional Test

    0.8:1 turns ratio was expected to be measured. Additionally, the displayed test results were interpreted as a test set calibration check. TTR20 test set is designed and optimized for the transformer turns ratio testing. It uses a mixed analog-digital technique to provide the accurate readings of the tested transformer turns ratio.

  • Page 37: Battery Replacement

    5. Replace the battery compartment door and secure it with screws. 6. Turn on TTR20. It should display the opening screen, then the battery level screen. The battery level displayed depends on many factors including type of battery installed, battery manufacturing date, battery storing conditions, etc.

  • Page 38: Troubleshooting

    Troubleshooting The Troubleshooting Guide, Table 5-1, is arranged to help you evaluate the reasons for TTR20 test set malfunction. The table lists possible TTR20 test set malfunctions which may be encountered during operation and lists possible causes. Electronic circuit repairs should not be attempted in the field. Refer to Repair section.

  • Page 39: Error Messages

    Maintenance and Troubleshooting Error Messages All TTR20 error messages are divided by 3 categories: self-test error messages, test error messages, and miscellaneous error messages. The self-test error messages may appear on the opening screen during power-up self-test procedure. The Table 5-2 below shows the messages.

  • Page 40: Table 5-4 Miscellaneous Message

    Error Message Description of error and action required CONNECTIONS H and X test lead connections are reversed. REVERSED Connect H and X test leads properly. TURN RATIO >10,000 The tested turns ratio is higher than 10,000:1. Causes test to stop. Check for bad or open test lead connections.

  • Page 41: Repair

    Maintenance and Troubleshooting Repair Megger offers a complete repair and calibration service and recommends that its customers take advantage of this service in the event of equipment malfunction. Contact your Megger representative for instructions and a return authorization (RA) number. Equipment returned for repair should be shipped prepaid and insured and marked for the attention of the Repair Department.
  • Page 42 AVTMTTR20 Rev 4 Dec 2015...

  • Page 43: Appendixa - Specifications

    12 hrs of continuous field operation when new Energizer X91 batteries or equivalent (with average capacity of 3135 mAh) are used Pollution Degree TTR20 is designed for Pollution Degree II Regulatory Compliance IEC 61010-1 Environmental Protection Dust and shower protection to IP54...
  • Page 44 Accuracy Turns ratio*: ±0.20% (0.8 to 4000) ±0.25% (4001 to 10,000) *For Excitation Current Values no greater than preset value Current (rms): ±5% of reading, ±0.5 mA Measurement Method In accordance with ANSI/IEEE C57.12.90-2013 and IEC 60076-1(2000) Transformer Winding Phase Relationship ANSI C57.12.70-2011 CEI/IEC 76-1:2011 Measuring Time...

  • Page 45: Environmental Conditions

    Printer port: DB-9 male connector Cable used: 9-pin D-type connectors, standard extension female-female RS232 cable (for TTR20 to a PC connection. The cable is not included in accessory supplied); 9-pin D-type connectors, null modem female-male RS232 cable (for the optional serial printer connection.

  • Page 46: Avtmttr20 Rev 4 Dec

    AVTMTTR20 Rev 4 Dec 2015...

  • Page 47: Appendixb - Ordering Information & Spare Parts List

    Combined test leads set, "X/H" winding, 20 ft,(6.1 m) 2007-713-20 Combined test leads set, "X/H" winding, 33 ft,(10.1 m) 2007-713-33 Test Leads - TTR20 (Discontinued) TTR20 Lead Set, 1.8 m (6 ft) 35938 TTR20 Lead Set, 3.6 m (12 ft) 35942 TTR20 Lead Set, 6 m (20 ft)
  • Page 48 AVTMTTR20 Rev 4 Dec 2015...

  • Page 49: Appendixc - Connections And Vector Voltage Diagrams

    ANSI standard. To make a measurement on a three-phase power transformer with TTR20 test set, match the vector diagram from the transformer nameplate to the corresponding winding connection diagram from Table C-2. Then connect the TTR20 test leads to the appropriate transformer winding terminals of phase A.

  • Page 50: Table C-1 Ansi Transformer Winding Phase Relationship

    To make a measurement on a T-type transformer, the jumpers indicated in Table C-1 should be applied to the appropriate terminals of the T-type transformer. The TTR20 measured turns ratio should be compared to the calculated turns ratio indicated in Table C-1.
  • Page 51 Appendix C Notes to Table C-2 Transformer terminal markings for distribution and power transformers marked in accordance with requirements of American National Standard Institute, Inc (ANSI) standard C57.12.70 – 2011. Definition of Symbol Designations External terminals on HV transformer winding. External terminals on LV transformer winding.

  • Page 52: Table C-2. Ansi Transformer Winding Phase Relationship

    Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks Single-phase...
  • Page 53 Appendix C Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio...
  • Page 54 Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks • 3...
  • Page 55 Appendix C Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio...
  • Page 56 Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks •...
  • Page 57 Appendix C Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks •...
  • Page 58 Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks Neutral...
  • Page 59 Appendix C Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio...
  • Page 60 Table C-2. ANSI Transformer Winding Phase Relationship Copyright 2009 Megger Winding Connection Winding Tested Winding High- Low- Diag Vector High-Voltage Low-Voltage Phase Shorted Voltage Voltage Measured Group Winding (H) Winding (X) Tested By TTR Winding Winding Turn Ratio Remarks Neutral accessible •...

This manual is also suitable for:

Ttr20-1

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