Bench testing a condenser on batt ign.

[37 chief]

I have seen condensers go bad, and act like a fuel problem. Seams there is always a condenser laying around someplace, solution just replace the thing, and see what happens. I have a motor with a special mounted condenser. I just hate to drive around looking for the correct part, then finding out the old condenser is still good. How can a condenser be checked? Thanks Stan

 

[teddy52food]

Get a condenser tester.

 

[BCnT]

put the condenser in a vice with pigtail up...hook up a 12 volt battery to jumper cables and hook negative to vice and barely touch pigtail with positive...that will charge it...now touch pigtail to condenser case...it should spark if its good.
i remember good ole days in different shops i worked in...charge a condenser up and toss it to the new guy hehehehehehe

 

[RoySC]

You can use a Volt Ohm Meter (VOM), setting the meter on Ohms and watching the meter movement. I think you should be able to google search on "using the VOM to check capacator". Basically the meter movement will shoot to infinity and then move back to zero....indicating a good cap...kind of hard to explain...but your google search should have some picture to show the meter and what to expect.
Good Luck......

 

[John T]

To do it right and really know its capacitance value i.e. if its reallyyyyyyyy what it should be, YOU NEED A REAL CAPACITOR TESTER......

That being said, you can use an analog Ohm Meter (like my Old reliable Simpson 260) to show if its BAD (like its open or shorted) but even if it passes that it dont really mean its prefectly good nor do you know its capacitance value and thats a fairly critical factor in the Kettering Points n Coil Ignition System. If its much too large in capacitance, the spark will be weak or non existent, if its too low in capacitance, the points will burn up prematurely and the spark weaker.

1) Discharge the condensor
2) Put the ohm meter on the R x 1 scale and connect its leads to the meter, it should read like an OPEN circuit. If it reads low ohms continuity, its shorted and BAD.
3) Discharge it
4) Put the ohm meter on the R x 10,000 scale and connect it to the condensor, the meter should initially swing over towards low resistance as the condensor charges up butttttttttt then it should "kick back" over towards infinity open once its charged. Thats called the "kick back test"

Hope this helps, got it?????????

John T

 

[mmidlam]

The standard name for a condenser is capacitor.You can get a capacitor tester on ebay for under $25. The simplest just check for size. The better ones check for leakage and the best have another check. I think its called absorption. I don't think the last check is needed foe none electrolitic (sp) capacitors.

 

[36 Coupe]

Condenser or capacitor were terms used for them in the 40s.Condenser stayed with autos while radio and tv changed to capacitor.Motor start capacitors are best checked by subbing a known good capacitor.

 

[Geo-TH,In]

Go to the ford blog on this sight. Page 12, I wrote a thread, "Condensor tester for Soundguy".
Come to find out Soundguy wasn't the right person, but the procedure using an ohmmeter, is written out.
LOL George.

 

[36 Coupe]

George,An ohmmeter wont catch capacitors with leakage.Leaky caps are usually way off the marked values.When the points open there are peak voltages of 2 to 3 hundred volts present across the condenser.Your 1.5 volt meter battery cant give you a good test.You have apply working voltage to a capacitor to get a valid test.Heres an example.I find a 10 mfd capacitor used in fence chargers often drops to 2 mfd.This weakens the discharge voltage delivered to the fence.If you checked this capacitor with your ohmmeter you would say it was fine.I started in radio tv service in 1951 and have never checked a capacitor with an ohmmeter.

 

[Geo-TH,In]

How many volts does your capacitor tester apply? I'm going out on a limb and say it's low voltage AC for safety reasons. Please measure the voltage it with a condensor in place and get back. Also, please measure the size of a tractor's condensor. I'm guessing it is less than 1 mfd, more like 0.1 mfd.

My test will cover opens and shorts. If you waited between reversing polarity, it will cover leaking too.

If a non-electroletic capacitor is leaky, how long will it take to self-discharge? The time it takes you to reverse polarity with an ohmmeter is a light years compared to the time between points opening. BTY, a digital ohmmmeter is 9v not 1.5v.

Are the caps on a fence charger electrolytic or non?

thanks,
George

 

[36 Coupe]

Two of my testers put out 450 volts.voltage is adjustable Most ignition condensers are .25 mfd magneto caps are less.A digital meter is powered by a 9 volt battery but you wont find 9v at the ohmmeter leads, that much voltage would destroy ICs and transistors.A leaky capacitor gets moisture inside, that makes it behave like a resistor.In circuit testers were useless years ago.Fence chargers use oil filled or electrolytic.I have found bad oil caps. While mica capacitors are thought to be very reliable Ive found many shorted and leaky micas.