Testing condensers question

[stanley]

I’m checking a bunch of condensers and getting some results I don’t understand.I am electrically challenged and the tester is cheap but here are pics showing result for one rated .22 mfd.I assume the two readings should be nearly the same and just have the decimal point in a different place?

[crosbyman]

the only good way to test condensers is  aside from obvious shorts, dead, no reading…. with a VOM and Cap meter  is to measure under load  at 250V +

see M.Mohat’s  excellent articles   on the subject and  offer  …if you write to him …..to supply  you with a a basic test box diagram you can build… I did and it works great

https://wrcoutboards.org/wp-content/uploads/2020/04/Part1_Condenser_Construction_Failure_Modes.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part2_Condenser_Testers_And_Testing_Correctly.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part3_Sizing_Condensers_Correctly.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part4_Repairing_Broken_Condensers.pdf

Joining AOMCI has priviledges 🙂

[stanley]

These are all condensers which have passed the test under load on my Graham Lee coil and condenser tester.The problem is when I test for the actual capacitance value of the condenser.The readings I get do not make sense. I assume that the values for two different “scales”should be equivalent for the same condenser,but they are not.I would like to know why they might not be.

[crosbyman]

different scales may…. apply   diff  test voltages on the probes which may or may not charge the capacitor to saturation…causing diff.  readings.

with another meter you could try to  measure the  cap. testing voltage on different  scales.

 

Joining AOMCI has priviledges 🙂

[jeff-register]

Capacitors, not condensers should have a very high volage rating, a fast charge/discharge rate & high dielectric rating. Your old caps are more than likely bad because the dielectric value has failed. I’ve never used the caps in “repairing caps” web page but the dielectric constant is very good. Please grt new caps to save headaches.

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