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Electric Arching on Y-Cap using No Clean Flux

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Joe L

#39414

Electric Arching on Y-Cap using No Clean Flux | 31 January, 2006

We used an Alpha Metals No Clean Solder Paste on our products. However at 50% humidity and above, electric arching starts to appear across our y-cap, when a hi-pot voltage of 1500V is applied across. At 20% humidity this situation does not occur. Also after cleaning with alcohol, even at 50% humidity, this situation does not occur.

Can anyone advice if they have seen similar situations ? And if so, how do they eventually prevent arching ?

Thanks, Joe

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KEN

#39418

Electric Arching on Y-Cap using No Clean Flux | 1 February, 2006

Your product may not no-clean compatible.

"No Clean" must not be confused with "no need to clean". Your end application, operating environment and circuit operation (form-for-function) will dictate your cleaning requirements.

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Rob

#39421

Electric Arching on Y-Cap using No Clean Flux | 1 February, 2006

That would be the lightning effect, with increased humidity reducing resistance.

1500 VDC or 1500 VAC?

What is the distance between the edges of the pads - i.e. not the pitch of the component, but the actual physical distance between conductors?

Also what is the manufacturer & part number?

There may be what we call creepage & clearance issues, & you may have to either:

1) reduce contamination, which along with humidity could be contributing to reducing the resistance between the legs

2) reduce the pad diameters to increase the insulation gap

3) go for a part with a larger lead pitch (distance between the legs) to have the same effect as the above.

Cheers,

Rob.

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slaine

#39431

Electric Arching on Y-Cap using No Clean Flux | 1 February, 2006

or conformal coat the cap.

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Rob

#39432

Electric Arching on Y-Cap using No Clean Flux | 1 February, 2006

Good point

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