Megger MT0300 Instruction Manual
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Megger MT0300 Instruction Manual

Megger MT0300 Instruction Manual

Transformer ohmmeter dc winding resistance test set
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Instruction Manual
Transformer Ohmmeter
DC Winding Resistance Test Set
Catalog Number MTO300
Catalog Number MTO330
Read this entire manual before operating.
for
MTO300
MTO330
M
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403-2329
U.S.A.
610-676-8500
www.megger.com
AVTMMTO3XX
Rev 3
Sept 2013

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  • Page 1 Rev 3 Sept 2013 Instruction Manual Transformer Ohmmeter DC Winding Resistance Test Set MTO300 MTO330 Catalog Number MTO300 Catalog Number MTO330 Read this entire manual before operating. Valley Forge Corporate Center 2621 Van Buren Avenue Norristown, PA 19403-2329 U.S.A. 610-676-8500 www.megger.com...
  • Page 3 Transformer Ohmmeter DC Winding Resistance Test Set MTO300/MTO330...
  • Page 4 Specifications are subject to change without notice. WARRANTY Products supplied by Megger are warranted against defects in material and workmanship for a period of one year following shipment. Our liability is specifically limited to replacing or repairing, at our option, defective equipment.

  • Page 5: Table Of Contents

    Table of Contents   1 Getting to know the MTO ..........................1   Product Overview 300/330 ..........................1   Top Panel Controls .............................. 2   2 Safety ..................................7   Safety is the responsibility of the user ....................... 7   General Safety Precautions ..........................
  • Page 6 List of Figures MTO300 Transformer Ohmmeter Test Set ......................iii   MTO330 Transformer Ohmmeter Test Set ......................iii   Figure 1: MTO300 Front Panel .......................... 2     Figure 2: MTO330 Front Panel .......................... 2     Figure 3. HOME Action Icons ..........................6  ...

  • Page 7: Mto300 Transformer Ohmmeter Test Set

    Prior to operation, check for loosened hardware or damage incurred during transit. If these conditions are found, a safety hazard is likely, DO NOT attempt to operate equipment. Please contact Megger as soon as possible. MTO300 Transformer Ohmmeter Test Set...
  • Page 8 AVTMMTO3xx Rev 3 Sept 2013...

  • Page 9: Getting To Know The Mto

    Getting to know the MTO Product Overview 300/330 The Megger Transformer Ohmmeter is a line-operated, field-portable instrument designed specifically to measure the DC resistance of all types of magnetic windings safely and accurately. Its predominant use is the measurement of the DC resistance of all types of transformer windings within the defined range of resistance.

  • Page 10: Top Panel Controls

    Top Panel Controls Figure 1: MTO300 Front Panel Figure 2: MTO330 Front Panel AVTMMTO3xx Rev 3 Sept 2013...
  • Page 11 Getting to Know the MTO Input AC Power Module: This module is an IEC320 interface to the mains power. The module has an integrated switch, fuse holder and input filter module. Above the module are the voltage, frequency and power requirements for the product.
  • Page 12 Remote Control Switch This connector is used to interface with a remote switch. This switch is primarily used when testing On-Load Taps of a transformer The Remote Control Switch can remotely start the MTO test and store multiple resistances reading for tap changes. The storage function in remote mode is sequential and occurs during a continuous resistance test.
  • Page 13 Getting to Know the MTO Page Down Button Large forms may have multiple pages of results. This button is used to toggle down the page sequence. Test Button Initiates and Terminates Testing. Tab Button Allows user to select active area of screen. Home Button Toggles HOME action icons.

  • Page 14: Figure 3. Home Action Icons

    Select to ZOOM-IN Select to ZOOM-OUT Print Icon. Prints the Selected Test Form. Printer driver is factory installed. Please contact Megger for specific printer model availability. Select to enter PREFERENCES screen Figure 3. HOME Action Icons AVTMMTO3xx Rev 3 Sept 2013...

  • Page 15: Safety

    In the event of equipment malfunction, the unit should immediately be de-energized and returned to Megger for repair. “The Safety precautions herein are not intended to replace your Company’s Safety Procedures. Refer to e.g. IEEE 62-1995/IEEE C57.152 and IEEE 510 - 1983, IEEE Recommended Practices for Safety in High-Voltage and High- Power Testing, for additional information.”...

  • Page 16: General Safety Precautions

    General Safety Precautions The MTO and the Unit Under Test (UUT) should both be considered as sources of instantaneously lethal levels of electrical energy. Observe the following safety precautions:  Observe all safety warnings on the equipment. They identify areas of immediate hazard that could result in injury or death.

  • Page 17: Input Power Precautions

    Safety WARNING No user serviceable parts inside! Refer all servicing to the factory or a qualified authorized service company! CAUTION Use only factory supplied mains cord! Mains cord shall not be substituted! Input Power Precautions This instrument operates from a single-phase, sine wave, power source. It has a three-wire power cord and requires a two-pole, three-terminal (live, neutral, and ground) type input source.

  • Page 18: Pc Interface Precautions

    PC Interface Precautions The MTO300 instrument was designed to operate as a peer to peer connection between a Personal Computer with Windows OS and the Test Unit.  Unit is NOT designed for network operation. DO NOT Connect MTO300 to a network. ...

  • Page 19: Preparing For A Test

    Making Circuit Connections Connections should be made in the order as listed below. 1. Ground. Use the Megger supplied Safety Ground Cable (15 ft (4.6 m)) to connect the MTO Wing Nut Ground Terminal directly to Local Station Earth Ground. Ensure that the Transformer chassis also has a low impedance connection to Local Station Earth ground potential.
  • Page 20 4. Connect the Ethernet Cable. If using a remote PC and PowerDB Lite software, connect the Ethernet cable from the MTO330 side panel or the MTO300 front panel to the PC Ethernet port. A standard RJ45 Ethernet cable will work fine for this application. Connect the PC Ethernet output to the MTO300 at this time.

  • Page 21: Operating The Mto300/330

    Operating the MTO300/330 When testing high-voltage transformers, caution must be used at all times and all safety precautions followed. Read, understand, and employ all safety precautions and circuit connections described in Section 2 Safety and Section 3 Preparing for Test. WARNING Ensure that the transformer to be tested is completely de-energized.
  • Page 22 TEST FUNCTION 1. Entering the test report information. 2. Entering the transformer nameplate information. 3. Starting the test. 4. Data Display. 5. Stopping the test 6. Populating the PowerDB table 7. Saving the data AUTOMATIC DISCHARGE FUNCTION Discharge of a transformer after testing is critical to prevent excessive voltage buildup across the transformer bushings upon removal of leads.
  • Page 23 Operating the MTO REMOTE TEST FUNCTION The main purpose of this function is to take sequential data to storage during a single test. It is useful for tap change testing where multiple resistance values are read in sequence with no interruption in current flow. 1.
  • Page 24 This section describes the method for changing the firmware on an MTO 300 and 330. ATTAINING THE LATEST SOFTWARE: The best way to attain the latest software is to visit Megger.com. Once you are on the site:  Select the country you are located in.
  • Page 25  The unit will have to be power cycled to exit boot loader mode. ATTAINING THE POWERDB SOFTWARE: The best way to attain the latest software is to visit Megger.com. Once you are on the site:  Select the country you are located in.
  • Page 26 AVTMMTO3xx Rev 3 Sept 2013...

  • Page 27: Transformer Testing

    Transformer Testing WARNING When testing a transformer or regulator, make sure that a good ground is placed on the test specimen as shown on all connection diagrams. Winding Resistance Testing Winding resistance measurements in transformers are of fundamental importance for the following purposes: ...

  • Page 28: Testing A Single-Phase Transformer

    Testing a Single-Phase Transformer Below are some graphics on the three methods of testing a single winding transformer. SINGLE-WINDING TEST Figure 4: Single Winding Measurement Primary or Secondary AVTMMTO3xx Rev 3 Sept 2013...

  • Page 29: Figure 5: Dual Winding Measurement (Primary And Secondary)

    Transformer Testing Figure 5: Dual Winding Measurement (Primary and Secondary) WARNING Do not disconnect leads until all indicators are OFF! PROCEDURE: 1. Connect line cord to unit and plug into 120 V/230 V socket. 2. Connect Safety GND cord from Top Panel to Transformer GND. 3.
  • Page 30 10. MTO300 - Select the form desired for use. This manual employs form number 56353/MTO300/330 Winding Resistance. 11. The form will be displayed and the user will be ready to start the process. 12. Selecting an existing form – this is handy for customers that have a form and transformer configuration they are using on a regular basis.
  • Page 31 Transformer Testing 16. Instrument Settings Button – Setup the MTO for the testing methodology of the instrument. AVTMTO3XX Rev 3 Sept 2013...
  • Page 32 a. The Title Bar for this window displays the program title (MTO Setup) and the version number of the program. b. Communications button – Indicates that the MTO is connected and communicating with the top panel (MTO330) or PC (MTO300). Green flashing and display of instrument serial number, firmware and calibration date indicate proper operation.
  • Page 33 Transformer Testing  Check MTO Power,  Check to make sure the Ethernet wire is connected.  Disable any wireless connections.  Check Ethernet configuration. a. Current (Amps) – pull down box for setting the current test level. b. Current Transition (BREAK/MAKE) Sensitivity (For detecting a current drop below 90% of the set current level) –...
  • Page 34 d. Resistance Stability – This is a pull-down item to select the level for acceptable resistance reading stability from one period of time (average data for 1 to 5 seconds) vs. a second period of time (average data for 6 to 10 seconds).
  • Page 35 Transformer Testing testing would be to measure the high and low side at the same time. This is the recommended test mode when measuring Low Voltage Delta connections. a. Two shortcuts are included for seasoned users. Right clicking on a specific resistance cell will start a test for that specific cell.
  • Page 36 e. The next question will be what row/s for the high voltage winding will be tested. If the transformer has no taps or the taps are defined as DETC, then the software will only allow Selected Row. f. The next question will be what row/s for the low voltage winding will be tested.
  • Page 37 Transformer Testing 18. Once selected, the instrument display module will start. This is a universal screen used for many transformer configurations. At the top is denoted the Transformer configuration, the continental standard selected and the nominal current selected for testing the transformer. AVTMTO3XX Rev 3 Sept 2013...
  • Page 38 19. The software will not automatically start testing as a safety precaution. A two step process is required to energize the test specimen. 20. Additionally, Instrument (Test) Setup can be quickly accessed from this screen in the event you want to check/change any settings before starting a test. 21.
  • Page 39 Transformer Testing the reading is valid. Customers have the choice of saving and continuing readings without a stable reading. Usually, this will be after a certain amount of time, the reading is 99% stable and the customer feels the readings are acceptable. If the Save Results button is pushed immediately after starting a test, then data could be saved with low stability numbers.

  • Page 40: Figure 6: Yn Reading Sequence

    Testing a Three-Phase Transformer Below is an outline of the test sequence. 1. Three-Phase Wye Configured Winding with Neutral Figure 6: YN reading sequence AVTMMTO3xx Rev 3 Sept 2013...

  • Page 41: Figure 7: Y Reading Sequence

    Transformer Testing 2. Three-Phase Wye Configured Winding, No Neutral Brought Out Figure 7: Y reading sequence AVTMTO3XX Rev 3 Sept 2013...

  • Page 42: Figure 8: Delta Reading Sequence

    3. Three-Phase, Delta Configured Winding Figure 8: Delta reading sequence AVTMMTO3xx Rev 3 Sept 2013...

  • Page 43: Testing Delta Configured Windings

    Transformer Testing Testing Delta Configured Windings Testing Delta winding resistance may be a very time consuming procedure, in particular LV winding deltas the correct balance time can take up to 30-60 minutes for a large transformer. The method for improving test time for delta configurations requires that both the high side and low side be connected in series with the MTO’s current source (see connection Table 1).
  • Page 44 TESTING TRANSFORMERS WITH TAP CHANGERS WARNING Make sure before changing taps to identify the types of tap changers on the transformer and test accordingly per instructions. Many transformers used today have taps built into them. These taps allow ratio to be increased or decreased by a few percent. Any of the ratio changes involve a mechanical movement of a contact from one position to another.

  • Page 45: Demagnetizing A Transformer

    Transformer Testing Because the instrument can be left on while changing from tap to tap, it is possible to take measurements without discharging. The MTO will re- balance after every tap change. If the current drops more than 10% for the selected transition time sensitivity, then the MTO will indicate there was a transition.
  • Page 46 5. Press the DEMAG Button 6. Press the START Button 7. The unit automatically cycles thru a preset arrangement of current levels to demagnetize the transformer after all of the resistance testing is completed. AVTMMTO3xx Rev 3 Sept 2013...
  • Page 47 Transformer Testing 8. The form will have a Demagnetized Transformer printed in the nameplate section of the form to confirm that a Demag was performed as the last operation of the transformer testing. Any additional testing of the transformer will clear this message. Temperature Correction It may be necessary to convert the resistance measurements to values corresponding to the reference temperature in the transformer test report.
  • Page 48 Temperature Entry If the transformer has winding temperature meters, use theses readings. Most transformers will have a meter for each winding. Most meters are reading about the same value for a static transformer. Use the average of the three readings and place this number in the Winding Temp field of the Transformer nameplate section of the form.
  • Page 49 Transformer Testing Manual Mode Operation At the bottom of the form is a separate table for manual mode operation. It may be required to perform testing that is not typical for a normal test sequence or to double check a measurement discrepancy generated in the normal test sequence. This manual mode operation creates the ability to test just use single or dual winding measurements with fixed output terminals and virtually unlimited connection opportunities.
  • Page 50 AVTMMTO3xx Rev 3 Sept 2013...

  • Page 51: Mto330/300 Series Powerdb Lite

    Introduction PowerDB Lite is a free, but limited capability, version of the PowerDB software tool that is designed specifically to control and/or extract data from Megger instruments. The primary difference between PowerDB Lite and PowerDB is that PowerDB is designed to work with all manufacturers’ equipment and has field and office synchronization capabilities.

  • Page 52: Software Installation

     Allows all of your field test data to be integrated with CMMS systems such as Maximo or SAP  Imports >From Many Other Industry Standard Software Applications  Controls and Imports Data from many non-Megger Instruments Software Installation To install PowerDB Lite, load the PowerDB Lite CD into your CD-ROM drive and follow the on-screen instructions.
  • Page 53 Service 2. Choose the destination location for the PowerDB Lite files. 3. Select Default Settings. AVTMTO3XX Rev 3 Sept 2013...
  • Page 54 4. InstallShield Wizard will complete the installation of PowerDB Lite. Click Finish to close the installation program. AVTMMTO3xx Rev 3 Sept 2013...

  • Page 55: Using Powerdb Lite

    Service Using PowerDB Lite 1. SELECTING AN INSTRUMENT Select your Instrument MTO3XX from the Instrument Setup screen. a. You can always view the Instrument Setup screen from the Tools menu or b. The MTO3XX uses Ethernet communication there is not need for communications setup.
  • Page 56 c. Click OK on the Instrument Setup Screen to finish. AVTMMTO3xx Rev 3 Sept 2013...
  • Page 57 Service 2. SELECTING A FORM Once you have defined the instrument, PowerDB will present the forms created in the database and associated with that instrument. The factory default form is 56352. 3. ENTER HEADER AND NAMEPLATE DATA a. Header and nameplate information can be manually typed into a form. b.
  • Page 58 4. OPENING AN EXISTING FILE a. Select the File> Open menu item. b. Browse to the file you would like to open. c. Press the Open dialog button. d. If the file contains multiple test dates, select the Date that you would like to open for editing or select New to append a new set of results to the file.
  • Page 59 Service 5. ACQUIRING DATA Follow instructions outlined in section 5 of the manual 6. COMMENTS AND DEFICIENCIES When imported into the full version of PowerDB, the comments and deficiencies on each form are used to generate summary reports. These summary reports repeat the notations and lists the page number where reported.
  • Page 60 7. SAVE THE DATA a. Select the File>Save menu item, or press CTRL+S, or press the Save toolbar button. b. The Save As screen will allow you to specify a location and file name for your PowerDB Lite XML file. AVTMMTO3xx Rev 3 Sept 2013...

  • Page 61: Using Powerdb Onboard (Mto330 Only)

    Service Using PowerDB OnBoard (MTO330 only) Navigating the screen Use Arrows keys to highlight desired action Use ENTER key (in center) to select highlighted action HOME Screen Action Icons Select HOME key to display Action Icons ACTION ICONS: Select NEW TEST to open new form Additional information to be added when software is released.
  • Page 62 5. ACQUIRING DATA Follow instructions outlined in Section 5 of the manual 6. COMMENTS AND DEFICIENCIES When imported into the full version of PowerDB, the comments and deficiencies on each form are used to generate summary reports. These summary reports repeat the notations and lists the page number where reported. This allows the user to scroll to a particular page to view a reported anomaly.

  • Page 63: Service

    Service Maintenance Maintenance should be performed only by qualified persons familiar with the hazards involved with high-voltage test equipment. Read and understand Section 2, Safety, before performing any service. Routine maintenance is required for the MTO test set. The appearance of the MTO test set can be maintained by occasionally cleaning the case, panel and cable assemblies.

  • Page 64: Calibration

    WARNING Before replacing the fuses, disconnect the power input plug from the live power source. To replace fuse(s), proceed as follows: 1. Disconnect the power cord from the MTO test set. 2. Using a small flathead screwdriver, carefully remove the fuse holder of the input power module installed on the right side of the MTO test set front panel.

  • Page 65: Repairs

    In the event that Service is required, contact your Megger representative for a product Return Authorization (RA) number and shipping instructions. Ship the product prepaid and insured and marked for the attention of the Megger Repair Department.

  • Page 66: Error Codes

    If the error persists, review the possible causes and determine if you can resolve the problem on site. If the basic cause a ruled out, contact Megger for additional assistance. Bold Error codes are quite common with the possible causes defined.
  • Page 67 MTO300 PowerDB Lite User Manual CODE Error Description Possible Cause ADC internal full-scale calibration failure Onboard 5 volt supply out of range, too high Onboard 10 volt out of range, too high Onboard 28 volt out of range, too high VICOR power supply temperature is out of range Discharge circuit temperature is out of...
  • Page 68 CODE Error Description Possible Cause Too much voltage ripple for the 25 volt reference Too much voltage ripple for the VICOR power supply at 5 volts Too much voltage ripple for the VICOR power supply at 20 volts Too much voltage ripple for the VICOR power supply at 40 volts UNDER status input failed OVER status input failed...
  • Page 69 MTO300 PowerDB Lite User Manual CODE Error Description Possible Cause voltage too low Onboard 10v out of range, voltage too low Onboard 28v out of range, voltage too low Discharge temperature is out of range, too Unit overheated, fans filters clogged, fans high not working, overuse, extremely hot test conditions...
  • Page 70 CODE Error Description Possible Cause ADC locks up, can not read ADC channel 4 failed HARDWARE_ERROR Discharge takes too much time VICOR protection failed, OVER is too long or too short to reset VICOR protection failed, OVER is too long or too short to set VICOR fast protection failed, OVER is too long or too short to reset...
  • Page 71 MTO300 PowerDB Lite User Manual CODE Error Description Possible Cause Relay test K1 off test failed Relay test K2 off test failed Relay test K3 on and K4on failed Relay test K3 off test failed Relay test K4 off test failed OVER and UNDER failed during winding resistance test Current calibration failed during winding...
  • Page 72 CODE Error Description Possible Cause Auto-range, voltage is too low Current = 0 Over didn't stay set for normal transistor protection test Over didn't stay set for fast transistor protection test Transistor protection med-low failed, OVER is too short to reset Transistor protection med-low failed, OVER is too short to set Fast transistor protection high failed,...
  • Page 73 MTO300 PowerDB Lite User Manual CODE Error Description Possible Cause Charge timeout error. AVTMTO3XX Rev 3 Sept 2013...
  • Page 74 AVTMMTO3xx Rev 3 Sept 2013...

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