Impulse Winding Tester 7750 Series

Specifications

Selection

Model	7750-1S	7750-1F	7750-5E	7750-5H	7750-5S	7759	7750-10S
Channel	1	1	1	1	1	9	1
Sampling Rate	200MHz/ 9bit	200MHz/ 9bit	50MHz/ 9bit	100MHz/ 9bit	200MHz/ 9bit	200MHz/ 9bit	200MHz/ 9bit
Voltage Output	10V-1200V		100V-5200V				200V-10000V
Lowest Inductance	≥ 0.1μH	≥ 0.1μH	≥ 16μH	≥ 4μH	≥ 1μH	≥ 1μH	≥ 20μH
Test Time	10 times/ Sec
Breakdown Voltage Test	●	●	–	–	●	●	●
LAN Interface	●	●	–	–	●	●	●
Waveform Analysis
Total area comparison	●	●	●	●	●	●	●
Differential area comparison	●	●	●	●	●	●	●
LAPLACIAN Comparison	●	●	–	●	●	●	●
Corona comparison	●	●	●	●	●	●	●
FLUT Comparison	●	●	●	●	●	●	●
COMP Comparison	●	●	●	●	●	●	●

SPEC

Pulse Number	Max. 32
Input Impedance	20MΩ
Measurement Statistics	●
Provides 6 waveform comparison

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.

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.

LAPLACIAN Comparison	Poor insulation quality of the coil results in discharge under high voltage impact, causing rapid changes in the oscillation waveform. By employing the 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.
COMP Comparison	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 in the winding coil, the waveform will exhibit tremors or fluctuations. Therefore, the instrument quantifies the degree of waveform tremors into numerical values for comparison.

SYSTEM

PLC Remote Control	Test、About
PLC Remote Output Signal	PASS、FAIL、HV Output、Testing
Built-in Storage	200 sets testing waveform
Power Supply	Voltage：98Vac-132Vac 或192Vac-264Vac
Power Supply	Frequency：50/60Hz ±5%
Power consumption	45VA
Environment	Temperature：10℃-40℃
Environment	Humidity：20-80%RH
Dimension	430x132x370 mm (WHD)
Weight	7Kg
Interface	USB Host/Device、RS-232、Remote、LAN GPIB (Option)
Display	7″ dot-matrix (800*480 )

MICROTEST 7750 Series is an advanced Impulse Winding Tester with a faster color display screen. It 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 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.

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= Quality and product life test

7750 Series 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.

Vs	Internal high voltage source
Sw	Internal control switch
Ri	Internal resistor
Cs	Storage capacitor
Rr	Resonant resistance
Cr	Resonant capacitor
Lr	resonant coil
DUT	device under test

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.

By comparing the wave of damping attenuation between golden sample and 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

7750 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.

Analysis the power loss by this data.

Area Differential 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 mode.

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 employing the 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.

electrical discharge or poor electrode welding

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.

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.

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.

7750 Power Function

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)

MICROTEST 7750 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.