New Run Motor Capacitor


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Old 11-06-15, 02:52 PM
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New Run Motor Capacitor

I just bought a new run motor capacitor and tried measuring the capacitance on it but did not get a reading at all. So I tried to measure its resistance and didn't get a reading on it either. So I tried the meter on my old capacitor and got readings on it so it's not the meter. Any ideas on what's going on with the new capacitor? Is it because it's never held a charge? Thanks!
 
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Old 11-06-15, 03:46 PM
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Just because you bought it new doesn't mean it is good.
 
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Old 11-06-15, 04:19 PM
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So I tried the meter on my old capacitor and got readings on it so it's not the meter.
You're right..... it's not the meter..... it's a leaky capacitor.

In order to check a capacitor correctly..... you need a meter that has a capacitor setting on it.

If you want to use an ohmmeter to make a basic check on a capacitor you connect the meter leads to the cap. The resistance should count up until it registers an open circuit. Then you take and reverse the leads..... the opposite should happen.

This test is easier to see on an analog meter.
 
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Old 11-09-15, 02:04 PM
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Right. I have the correct meter (digital) and used the capacitor setting on it but it never registered anything on the new capacitor but it did register a reading on the old capacitor before and after trying to read the new capacitor.
 
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Old 11-09-15, 04:01 PM
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Was the scale on the meter listed as reading as high as the cap you were checking ?
Some meters have a capacitance scale that only goes up to 10ufd or 20ufd.

Post the make and model of the meter is the specs are unknown.
 
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Old 11-09-15, 06:01 PM
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That's just it. The meter didn't read at all with the new capacitor. But it did read 023 with the old capacitor. It is an 8 uf capacitor. I'll get you the make and model of the meter tomorrow.
 
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Old 11-10-15, 11:09 AM
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The meter is a Greenlee DM-20.
 
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Old 11-10-15, 11:15 AM
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It would appear that the Greenlee DM-20 doesn't have a capacitor test setting.

greenlee/ebizcdn/5e98d23afe19a774d1b2dcbefd5103eb/DM-20
 
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Old 11-10-15, 09:44 PM
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Omgosh! I thought the diode symbol was the capacitance symbol lol. Now I'm wondering how I got a reading off of my old capacitor of 023 and if it means anything. Oh well, thanks so much! Now I will get the correct meter and then things will hopefully make better sense. But that's why I came here - because I know very little about electricity! Sheesh!
 
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Old 11-10-15, 09:48 PM
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As capacitors get old they get leaky. Your meter in the diode check mode was checking the capacitor for resistance.

Actually.... if you use that to check the new cap..... connect the probes to the new cap. Wait 10 seconds and then reverse the probes. You should see a reading then.
 
 

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