how do I know the capacitators are ok?
how do I know the capacitators are ok?
Soldered 3 capacitators to my motor. Seemed fine before I did that but how do I know they werent damaged in the process? How do I know they're doing what they're supposed to be doing?
- Coelacanth
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Re: how do I know the capacitators are ok?
First you need to confirm they're soldered on firmly. I'd say most issues with motor capacitors would be flaky solder jobs.
If you can say for sure they're soldered on, you can take a close look at the tops of the capacitors. They're designed to expand outward if they blow. If the top of a capacitor is raised or you see any kind of discoloration (usually brown) emerging from that area, the capacitor was blown. You might also take a sniff and see if you can smell a burnt smell.
I use the same method to see if capacitors on a computer motherboard have blown out.
If you can say for sure they're soldered on, you can take a close look at the tops of the capacitors. They're designed to expand outward if they blow. If the top of a capacitor is raised or you see any kind of discoloration (usually brown) emerging from that area, the capacitor was blown. You might also take a sniff and see if you can smell a burnt smell.
I use the same method to see if capacitors on a computer motherboard have blown out.
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Re: how do I know the capacitators are ok?
The solder-joints are fine but there is some discoloration around the legs on at least one of them (had to extend them as they were only a few millimeters long). Haven't noticed any smell yet.
- filzemail
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Re: how do I know the capacitators are ok?
You said that you "extended" the capacitor leads. I think that the best way to have a troublefree straight forward install is to get caps with correct length leads. Every joint is a potential trouble spot later on after everything has been jolted, moved around during use. If the soldering is borderline, you will have problems. Save youself future headaches. The finished joint should appear shiny and rounded like a bead. If the joint looks gray or dull, it will come back to bite you at the worst time, called a cold solder joint. There are many soldering videos on utube that will help quide you to a solid clean install.
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Re: how do I know the capacitators are ok?
Tell me about it.Coelacanth wrote:First you need to confirm they're soldered on firmly. I'd say most issues with motor capacitors would be flaky solder jobs.
If you can say for sure they're soldered on, you can take a close look at the tops of the capacitors. They're designed to expand outward if they blow. If the top of a capacitor is raised or you see any kind of discoloration (usually brown) emerging from that area, the capacitor was blown. You might also take a sniff and see if you can smell a burnt smell.
I use the same method to see if capacitors on a computer motherboard have blown out.


http://en.wikipedia.org/wiki/Capacitor_plague
- Mindwarp
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Re: how do I know the capacitators are ok?
ESR tester (equivalent series resistance), test capacitors in cct.
Something like this http://midwestdevices.com/ (not vouching for that company, just showing what an ESR tester is)
Something like this http://midwestdevices.com/ (not vouching for that company, just showing what an ESR tester is)
- Frankentruck
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Re: how do I know the capacitators are ok?
This seemed like a good topic to bump up with a new post. I've never seen disc capacitors soldered across the + + and the - - terminals before. I don't see how that would do anything, unless a change builds up there.
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- GoMachV
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Re: how do I know the capacitators are ok?
Trinity (and others) used electrolytic caps for the +/- and ceramic for the grounds. Not sure why they went that route but it was pretty common in the earlier days to see them.
- RogueIV
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Re: how do I know the capacitators are ok?
Those ceramic caps are doing nothing, Possible the solderer misunderstood the directions.Frankentruck wrote: ↑Mon Feb 10, 2025 5:42 pm This seemed like a good topic to bump up with a new post. I've never seen disc capacitors soldered across the + + and the - - terminals before. I don't see how that would do anything, unless a change builds up there.
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Re: how do I know the capacitators are ok?
But this is weird.
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Re: how do I know the capacitators are ok?
That was my thoughts too, but wanted to see if I was missing something.RogueIV wrote: ↑Mon Feb 10, 2025 7:47 pmThose ceramic caps are doing nothing, Possible the solderer misunderstood the directions.Frankentruck wrote: ↑Mon Feb 10, 2025 5:42 pm This seemed like a good topic to bump up with a new post. I've never seen disc capacitors soldered across the + + and the - - terminals before. I don't see how that would do anything, unless a change builds up there.
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1000014308.jpg
1000014307.jpg
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Re: how do I know the capacitators are ok?
Yeah they are doing nothing.
They should be from each brush hood to the motor can or motor tab(if a modified).
Electrolytic is also fine but a ceramic cap would be sufficient. If you haven't sat there and cooked the cap it should be fine, they are pretty tough. I've discolored the end of the potting a time or two at the leads.
They should be from each brush hood to the motor can or motor tab(if a modified).
Electrolytic is also fine but a ceramic cap would be sufficient. If you haven't sat there and cooked the cap it should be fine, they are pretty tough. I've discolored the end of the potting a time or two at the leads.
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Re: how do I know the capacitators are ok?
This motor is just going into my Parma collection, so the caps are all coming off. I just was puzzled by how the little brown turds had been installed.
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Re: how do I know the capacitators are ok?
You can't use an reversing esc with the electrolytic caps.
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Re: how do I know the capacitators are ok?
The installer was also puzzled.Frankentruck wrote: ↑Mon Feb 10, 2025 8:31 pm I just was puzzled by how the little brown turds had been installed.

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