Failure of Polyester Laminated Automotive Ignition Coils Influenced by Environmental Factors

Nawaz, Ahmad; Islam, Bilal; Akhtar, Rulia; Alamgir, Khalid; Noor, Siti Zaliha Mohammad

doi:10.1007/s13369-015-1789-4

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…However, partial discharges occur more severely in cylindrical-shaped bubbles than in circular bubbles. Similarly, bigger bubbles and higher relative humidity provide suitable conditions for partial discharges and corona [24,30].…”

Section: Discussionmentioning

confidence: 99%

“…Afterward, an endurance test (JIS D-5121) is performed on a hundred coils randomly selected from both the lots (the existing and the proposed method) on the aforementioned machine. Coils are subjected to the motor running at 3000 rpm and 20 kV voltage is applied between two electrodes at a three-point spark gap of 12.5 mm, continuously for 300 h as per the JIS standard [23,24]. Finally, after-sale warranty claims analyses of coils within two-year periods of usage are also considered for existing and modified lots of coils.…”

Section: Testing Sample Coilsmentioning

confidence: 99%

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One Factor at a Time Analysis to Modify Potting Technique for Manufacturing of Bubble-Free High-Voltage Polyester Insulated Automotive Coils

Nawaz

Ahmad

Akram

et al. 2022

Designs

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The current study focuses on minimising the bubbles in polyester-insulated ignition coils, which were produced with a defect level of ~21–25% or 210–250 coils per 1000 batch size by using the potting method. This high-level rejection makes a substantial financial impact by increasing waste material, manufacturing, and after-sales costs. Hence, to control the bubbled problem without using expensive and maintenance-heavy techniques, the process parameters in the potting method were alternated and investigated using one factor at a time, which played a vital role in the formation/reduction of bubbles in the ignition coil insulation. Process parameters, including pre/process heating, the appropriate MEKP/cobalt naphthenate ratio, the pouring amount/increments, and the stirring speeds, reduced the bubble formation per lot from 205 ± 30 to 146 ± 25, 108 ± 21, 61 ± 17, and 10 ± 2 per 1000 lot accordingly. In addition, a comparative study was conducted in terms of performance and life cycle endurance, using Japanese and Indian standards. Furthermore, an after-sale warranty claim also supports the proposed changes in the potting technique. This modification may reduce the after-sales rejection within two years to approximately ~85%. This modification in the potting technique is extremely cost-effective in comparison to expensive processes, i.e., vacuum-pressure impregnation and vacuum impregnation, which require extensive labour and maintenance.

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Section: Discussionmentioning

confidence: 99%

Section: Testing Sample Coilsmentioning

confidence: 99%

One Factor at a Time Analysis to Modify Potting Technique for Manufacturing of Bubble-Free High-Voltage Polyester Insulated Automotive Coils

Nawaz

Ahmad

Akram

et al. 2022

Designs

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An alternative and indirect statistical modeling method for viscosity estimation and its experimental validation for low styrene content polyester resin

Nawaz

Islam

Ijaz

et al. 2018

Polish Journal of Chemical Technology

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We propose an indirect method of ASTM D-1200 for measurement of viscosity from 0.1 to 30 stokes (St) using Ford cup 5 (range 2~ 12 St) by developing a statistical relation. General purpose low styrene content polyester resin (without adding initiator, hardener and accelerator) was used for viscosity measurement. In existing ASTM D 1200 standard, ford cups (1-4) are used to measure the viscosity up to 2 St, while fifth cup is used for measurement from 2 to 12 St. Viscosity above 12 St is not estimated using existing ASTM D- 1200 method. In contrast, our method and statistical relation proposed in this paper estimates viscosity in the flexible range of 0.1 to 30 St by using Ford cup 5 only. The estimated values were confirmed by existing ASTM D-1200 (0.1 to 12 St) and by using Ubbelohde viscometer (12 to 30 St). Values estimated above 12 St are from the proposed model are also in good conformance (percentage error ~ 5% or less) with experimental results. The satisfaction level of the estimated values with the experiments suggests that the model has also the potential for application to paints, polymer and oil industry.

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Failure of Polyester Laminated Automotive Ignition Coils Influenced by Environmental Factors

Cited by 2 publications

References 10 publications

One Factor at a Time Analysis to Modify Potting Technique for Manufacturing of Bubble-Free High-Voltage Polyester Insulated Automotive Coils

One Factor at a Time Analysis to Modify Potting Technique for Manufacturing of Bubble-Free High-Voltage Polyester Insulated Automotive Coils

An alternative and indirect statistical modeling method for viscosity estimation and its experimental validation for low styrene content polyester resin

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