Impulse winding tester MICROTEST 7750 series

Impulse winding tester MICROTEST 7750 series is an advanced Voltage pulse meter with a faster color display screen.

I. Specification of Impulse winding meter MICROTEST 7750 series

• MICROTEST 7750 series provides pulse voltage outputs of 1200V/5200V/10000V and utilizes high-speed sampling technology at 200MHz/9 bits.
• It offers various comparison modes such as total area, area difference, corona count, jitter count, second-order differentiation, and waveform comparison. With a testing speed of up to 10 times per second, it is ideal for high-speed production lines.
• For testing small components, the optional 7750-1S Impulse winding tester comes with the FX-IM0001 four-wire SMD component testing fixture. It features voltage compensation to minimize voltage errors caused by wiring and equivalent inductance, ensuring accurate quality control for products with small inductance.

Features:

• Lowest inductance ≥ 0.1μH
• Voltage compensation function
• 200MHz/ 9bits high impulse test sampling rate
• Built-in storage 128 sets testing waveform
• Programmable impulse voltage
• Breakdown voltage analysis
• Total area comparison
• Differential area comparison
• LAPLACIAN comparison
• CORONA comparison
• FLAT comparison
• Support USB host/device, RS-232, SIGNAL I/O.

Applications:

• Low inductance coil
• High power inductance
• Relay
• Transformer
• Motor stator
• Motor rotor
• Winding component.

II. Key feature of Impulse winding tester MICROTEST 7750 series

What is Layer short ?

• A magnetic component whit a lot of winding. However, the coil will cause short when the insulation has problem.
• If this happened, the magnetic field will be changed. This will affect the efficiency of whole system.

Why will short happened on winding ?

• The process of enameled wire:

The process of painting may scratch the wire.

Crack on the wire.

• Winding process:

Hook/Our of order/ Envelop

Winding span

Tin attached.

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

• 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.
• Impulse Test is Quality and product life test.

Impulse winding tester MICROTEST 7750 series with 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:

• When short happened on coil, it may change the parameter of inductance , capacitance, and resistance. The insulation ability reduce. Usually, the problem will be discover under high voltage.
• Without the high voltage, the defection point is hard to be penetrated
• So, it’s hard to find the problem from inductance , capacitance ,and resistance.

Wavefrom comparison:

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

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

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

III. Impulse winding tester MICROTEST 7750 series provides 6 waveform comparison

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. To determine the degree of waveform overlap.

DIFF 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.

LAPLACIAN comparison (corona waveform of high-frequency):

• Poor insulation quality of the coil results in discharge under high voltage impact, causing rapid changes in the oscillation waveform.
• By the corona waveform of high-frequency to know more about the insulating property of products.
• By employing the MICROTEST 7750 second-order differentiation algorithm, the maximum discharge capacity is obtained, effectively detecting quality issues related to electrical leakage caused by poor solder joints in the monolithic inductor.

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.

COMP comparison:

• During high-voltage pulse testing of the winding coil, the self-insulation system gets damaged, resulting in sharp discharge. The occurrence of corona can be observed in the discharge curve through waveform display. This functionality allows for counting the frequency of corona events and determining their deviation level for assessment.
• By setting an allowable waveform range for the standard wave, this feature can simultaneously determine the amplitude and phase of the resonant wave. It enhances the detection capability of inter-turn short circuits.

FLUT comparison:

• When there is inter-turn discharge occurring in the winding coil, the waveform will exhibit fluctuations or tremors. Therefore, the instrument quantifies the degree of waveform tremor as a numerical value for comparison.

IV. Power function of Impulse meter MICROTEST 7750 series

Voltage compensation function:

• MICROTEST 7750 features the Voltage compensation function. In order to reduce the possibility of misjudgment.

Safety Test-BDV mode (Breakdown voltage test):

• Impulse winding tester MICROTEST 7750 series supports breakdown voltage analysis function, which allows for setting the following parameters for the winding component:

Starting voltage

Ending voltage

Minimum percentage of voltage rise at the starting voltage.

• In the second-order differentiation mode and corona count comparison mode, it determines whether the values exceed the set standard. This verifies the withstand voltage strength of the tested winding component.

MICROTEST 7750 Support checking output voltage:

MICROTEST 7750 series Impulse tester 200MHz/9bit  High impulse test sampling rate:

Technical data of Impulse winding tester MICROTEST 7750 series

System: