Gary0747 Posted June 1, 2019 Report Posted June 1, 2019 Mags came off for 500 hour inspection. We tested the capacitor on each and found one that was bad showing very low resistance. I saw no apparent symptoms of a bad mag while flying prior to finding this. Does anybody have experience with seeing how a bad capacitor effects engine performance? 1 Quote
Mjknick@gmail.com Posted June 1, 2019 Report Posted June 1, 2019 Mags came off for 500 hour inspection. We tested the capacitor on each and found one that was bad showing very low resistance. I saw no apparent symptoms of a bad mag while flying prior to finding this. Does anybody have experience with seeing how a bad capacitor effects engine performance? Bad capacitor will cause points to arc and burn and go bad. Sent from my iPhone using Tapatalk Quote
Guest Posted June 1, 2019 Report Posted June 1, 2019 And overheat the plastic cam, melting it causing the mag stop making sparks. Clarence Quote
Guitarmaster Posted June 1, 2019 Report Posted June 1, 2019 Making Sparks good.... No make Sparks, bad.Sent from my Pixel 2 XL using Tapatalk 1 Quote
RLCarter Posted June 1, 2019 Report Posted June 1, 2019 While the mags are off why not just replace the points and capacitors? Quote
Hank Posted June 1, 2019 Report Posted June 1, 2019 12 hours ago, Guitarmaster said: Making Sparks good.... No make Sparks, bad. BTDT. No make sparks awaynfrom home, More Bad! Never have understood why it's acceptable for an A&P to take advantage of travelers in distress . . . . My out-of-town mag removal, ship off for overhaul and reinstall was > 1.5 AMU . . . . 1 Quote
carusoam Posted June 1, 2019 Report Posted June 1, 2019 Wait a minute... How did you/they test the capacitor? Resistance of a capacitor? Or capacitance? I thought their resistance was supposed to be infinite... electrons are stored on internal surface area... if they leak through to the other side, they drain out... Might be a typo, or my misunderstanding? PP thoughts only, not a mechanic... Best regards, -a- Quote
Gary0747 Posted June 2, 2019 Author Report Posted June 2, 2019 Slick manual in the 500 hour inspection specifies the resistance between the capacitor case and main terminal. It also specifies the capacitance. 1 Quote
thinwing Posted June 3, 2019 Report Posted June 3, 2019 On 6/1/2019 at 11:07 AM, carusoam said: Wait a minute... How did you/they test the capacitor? Resistance of a capacitor? Or capacitance? I thought their resistance was supposed to be infinite... electrons are stored on internal surface area... if they leak through to the other side, they drain out... Might be a typo, or my misunderstanding? PP thoughts only, not a mechanic... Best regards, -a- Resistance check is a quick way to detect dielectric short...ie if using a simple continuity checker...continuity center wire to case =bad cap 1 Quote
bob865 Posted June 5, 2019 Report Posted June 5, 2019 On 6/1/2019 at 2:07 PM, carusoam said: Wait a minute... How did you/they test the capacitor? Resistance of a capacitor? Or capacitance? I thought their resistance was supposed to be infinite... electrons are stored on internal surface area... if they leak through to the other side, they drain out... Might be a typo, or my misunderstanding? PP thoughts only, not a mechanic... Best regards, -a- If I remember right, you can figure it out by measuring resistance. It's a completely dead/not completely dead test, not a quality test. You have to make sure it's discharged first. It should read realy high, when you first connect the leads and then drop to almost 0. This high resistance being the volt meter charging the capacitor and then dropping to nearly 0 when it's charged. I could be backwards or completely wrong. It's been a while since electronics a-school in Pensacola. 1 Quote
Mjknick@gmail.com Posted June 5, 2019 Report Posted June 5, 2019 https://www.aircraftmagnetoservice.net/magneto-troubleshooting-guideSent from my iPhone using Tapatalk Quote
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