testing condensors microfarods

[ronboonville]

I don’t understand what is good or bad.  My old condensers test 0.310 and 0.302.  My new ones quick silver test 0.28 and 000. this is on my 55hp chrysler with mag ignition. I have several used ones that test around 0.300 and higher.  are the old ones acceptable?

[frankr]

I’d say you are good to go.  General rule of thumb is +/- 20%

[ronboonville]

I don’t know the rating of old condensers.

 

[joecb]

Ron said… “I don’t know the rating of old condensers.”

Please elaborate, what don’t you understand?   As Frank said the old style condensers were at best +/- 20%  of the nominal rating.  Pretty sloppy, I’d say, but apparently not that big a deal in practical application.  If you look at reference charts for recommended capacitors you will notice that, with few exceptions they are around  .22 mf . If you apply the +/- 20% that gives you a pretty broad range to work within. The newer “high tech” caps like the mylar foil caps are made to a higher standard, buy still +/- 5% of  nominal rating.

Hope that helps…

Joe B

[Mumbles]

I believe  Chrysler used two different mags in these motors, maybe Prestolite and Wico, as there are two different points and condenser sets listed for the 55’s depending.  Another forum suggests the condensers should be in the 0.16 – 0.20 uF range. As condensers age, the uF rating goes higher so yours would be way out of spec if 0.18 +/- is what they  were originally.  While the uF rating is important to protect the points from excessive arcing and pitting, what’s more important is if they are leaking internally or not. A Merc O Tronic ignition tester or a cap tester used in electronics testing can do this test.

• This reply was modified 3 years, 8 months ago by Mumbles.

[crosbyman]

gents  we have caps   referred to  here as .310 uf         .22uf  .016 to .020 uf … quite a spread !  or… were those .310 actually 310Nf ?

it would be important to have  cap specs for the  specific chrysler engine  and  remember the  conclusions of M.Mohat excellent study (Outboarder)  on capacitor tolerances.

Secodly testing at low voltages provided in typical VOM style meters isn’t  very conclusive as to the “useability”  of the tested caps .  Cap testing needs to done  at 275VDC  and  up voltahes to provide a good sense of confidence.  His little (basic) test box works very well imho. Has indicated by Mumbles….true cap  testers are essential !

Microsoft Word – Part2_Condenser_Testers_And_Testing_Correctly.doc (wrcoutboards.org)

soryy I know I am preaching to the  wise  here but I though those cap ranges were all over the map.

Microsoft Word – Part3_Sizing_Condensers_Correctly.doc (wrcoutboards.org)

 

Joining AOMCI has priviledges 🙂

• This reply was modified 3 years, 8 months ago by crosbyman.

[outboardnut]

delete

• This reply was modified 3 years, 8 months ago by outboardnut.
• This reply was modified 3 years, 8 months ago by outboardnut.

[outboardnut]

oops
sorry that is for coil tester
Can’t find condenser tester plans

[crosbyman]

part 2 comment …

For those that are interested in building their own Condenser Insulation Breakdown
Tester (for less than $30) using my design, the schematic diagram, parts list and some
simple instructions can be obtained by contacting me directly at:
wmohat@hotmail.com
Please note: I strongly suggest that you DO NOT attempt to build this tester if you
don’t have some experience building electronics projects in the past. Just…..don’t.

3 models are shown in the article  but the basic one works very well and easy to build .  no more guessing and  the occasionnal zap on the fingers   🙂

 

 

Joining AOMCI has priviledges 🙂

[frankr]

I figured the decimal point confusion would result.  .22 (0.22) would be reasonable.  .022 would not.  And what’s with the 000 in the OP?

Now I’m getting confused too (not hard to do).

[Author]

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