Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel)

Price: Contact

Model MT-6920
Manufacturer MICROTEST
Power supply 90-132Vac or 198-264Vac
Weight N/A
Size N/A
Condition Stocking
Warranty 12 months

Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel) combines the Interlayer Short-Circuit Tester (6920), the High Voltage Withstand Tester (7605), and the Multi-Channel Control Box (6908), with the 6920 serving as the main controller.

I. Specification of Engine Rotor testing machine MICROTEST MT-6920 (24/48 Channel

Motor Rotor testing system MICROTEST MT-6920 allows for the configuration of all measurement parameters and provides 24/48 test channels.

The external PC software enables direct real-time access to test results from the 6920, as well as report generation and direct uploading of test results to a database.

MICROTEST MT-6920 offers 24/48 channel testing capability for measuring the welding resistance of motor rotors. It integrates safety compliance, high-voltage insulation, and coil interlayer short-circuit testing into one system.

Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel) supports remote programming and data storage via PC connectivity software and can be equipped with PLC control. Customized test fixtures can be provided for rotor testing according to customer specifications.

  • 24/48 Channels
  • Hipot/Leakage Current
  • Insulation Resistance
  • Winding Layer short Test
  • Resistance Welding Test
  • Inductance Test
  • It can test multiple sets of DUTs simultaneously
  • 4-Wire DC Resistance measurement will be more accurate than others
  • The Impulse/Surge with waveform comparison is a non-destructive analysis
  • Storage file up to 100 sets
  • PC connection data analysis software is available
  • Chinese/English screen could be switched arbitrarily.

II. Main function of Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel)

Rotor Coil and Rotor Core:

  • Rotor core is made by 0.5mm silicon steel. Medium and small AC motor’s rotor core are mostly apply on shaft. Huge motor usually apply on steady than stick on the shaft.
  • Rotor coil is to conduct current and create inductance. There are two type of winding, squirrel-cage and wound.
  • Squirrel-cage rotor is self-closing winding. There is a conduct bar in each steady and connect both side.
  • Wound winding rotor is insert insulate wire into core as three phase winding set and connect on slip ring. And lead the current by brush.


Quality Issue on Enameled Process:

  • The process of covering insulation paint may scratch the wire.
  • VCrack on wire.

Process of Winding:

  • Hook/ Out of order/ Envelope
  • Winding Cross
  • Tin attached.


Uneven DCR happen in 3-phase motor, this will cause uneven rotate:

  • MICROTEST MT-6920 4-Wire DC Resistance measurement will be more accurate than others.


Customized test fixture for Rotor coil:


For Enameled Winding of Motor:

  • Conduct coil’s quality issue.
  • Layer Short Between Winding
  • Short on cross winding
  • Pin Short
  • Insulation Defect.

Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel) is One-Step-Test FunctionLow Voltage Electrical Test + Hipot Test  + Layer Short + Resistance Welding Test.


Introduction of Impulse tester:

  • Impulse Winding Tester use the comparison of pulse to measure the DUT. The instrument provide high voltage to do the instant pulse test and record the wave. Compare with the golden sample to define the product.


Why do we need impulse tester for producing motor/transformer?

  • Impulse Test = Quality and product life test
  • The small defection is hard to find at low voltage test station. As the DUT goes to the final assembly test, the defect may show up. This will higher the cost of production.
  • Motor and transformer usually work under high voltage. If we add impulse test in the product line, this may prevent the malfunction or burn on motor.



  Is the DUT coil

  C1, C2

  Are the resonant capacitors in the instrument

  R1, R2, R3

  Is the resistant in the instrument and the DUT

Technology of Detect Layer Short

→ 1

  Charge the C1 capacitor to the certain testing voltage level.

→ 2

  Trigger the SCR by pulse

→ 3

  DUT will resonate with C1 and C2


Technology of Detect layer short:

Pulse voltage and waveform comparison” is the way we detect layer short. The pulse voltage is non-destructive/instant voltage that apply on both side of winding and detect the DUT without damage it. By compare the wave with the golden sample, we can judge the DUT.

Damping wave under L/C resonate comes from the feature change of defect coil.

  • Inductance of coil
  • Q rate
  • Turn ratio of coil(voltage different)
  • Material of core
  • Layer short in the coil.

By comparing the wave of damping attenuation between golden sample and DUT:

Provides 5 waveform comparison:

  • Total area comparison
  • Differential area comparison
  • Wave comparison
  • Flat comparison
  • Corona comparison.


Technical specifications of Motor Rotor testing system MICROTEST MT-6920 (24/48 Channel)







Evaluate whether to include PC connectivity software.


Operate directly on the instrument 

PC Link

Production Traceability Management – Implementing Bar Code/Label Printer/Laser Engraver


Store test file sets

100 sets (existing instruments)

Unlimited (according to PC memory)

Sharing test files between devices

Unable to share, recreate the file

Share through PC software

Accessing test data


Transfer test data to the PC via the RS-232 interface

Uploading test data to a cloud database


User Permission Management” or “User Access Control


Supports permission management, configuration through Engineering Mode

CPK Report



Customized CPK Report According to Customer Requirements






Test Channel


DC Resistance Test

DCR Range


Measuring Mode


DCR Accuracy

Low Resistance


High Resistance


Safety Hi pot Test

AC Output Voltage


AC Leakage Current


AC Arcing Detection

Detect gears from 0-9

DC Output Voltage


DC Leakage Current


DC Arcing Detection

Detect gears from 0-9

IR Output Voltage


Insulation Resistance


Measuring Time

0.1-99.9s Continuously adjustable

Voltage Accuracy

±(3% of setting+5V)

Impulse Winding Test

Impulse Voltage (programmable)


Impulse Voltage Accuracy


Total area comparison

When layer short happened, the loss of power on coil increase, the resonance damping coefficient increase, resonance amplitude decrease, the total area decrease. These are the basic parameters we check layer short.
By calculating and comparing the deference of area between golden sample and DUT.
Show by percentage
Analysis the power loss by this data.

Differential area comparison

Add up the difference between normal wave and DUT wave call “ Area differential”.
When layer short happened, the inductance reduce(similar the transformer). The wave phase change and the area differential also change. This will show “fail” on the instrument.
However, the parameter might cause deviation because of the deviation of inductance, resonance phase shift. (Silicon steel product such as motor and traditional transformer is not suitable)

By calculating and comparing the deference of area between golden sample and DUT. To determine the degree of waveform overlap.
Compare the inductance by this.

Wave comparison

Set a acceptable wave range, if the DUT’s wave is in this range shows “pass” otherwise, “fail”
This parameter can judge both amplitude and phase of resonance wave. This can increase the detection capability of layer short.

Corona comparison

In pulse test, the insulation defect will cause discharge and create corona. This function is able to count the times that corona happened base on the degree of deviation.
Detect the discharge phenomenon on the coil.

Flat comparison

If the layer short happened, the waveform will tremble. Therefore, the instrument will quantize and compared it.

Inductance Measurement (Option LCR Meter 6365)

Inductance Ranges

0.1nH – 99.999KH

Test Frequency


Frequency Output Accuracy


Frequency Resolution

5 Digits

AC Drive Level

10mV to 2Vrms (1m Vrms resolution)

Basic Accuracy


Three-phase Inductance Balance Test

Comparison Mode

 – The absolute value of the difference between the two sets of coil inductance
 – The ratio of the absolute value of the difference between the two sets of coil inductance to the standard value
  – The ratio of the absolute value of the difference between the inductance of the two sets of coils and the average value of the measured resistance of the three sets of coils



Test fixture

According to the test requirements


Pass/Fail Screen Diaplay/Sound

Built-in Storage

Storage of 100 rewritable data sets


Manual, RS-232

Power Supply


90-132Vac or 198-264Vac



Power consumption









5.7″ dot-matrix display (320*240)


4.3″ TFT LCD (480*272)

Dimension (W*H*D)









15 Kg


14 Kg


3 Kg



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