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-   -   Power Cap (https://www.rctech.net/forum/electric-road/1045-power-cap.html)

jcr 10-21-2001 08:17 AM

Power Cap
 
Is there any difference between the Power Caps in R/C compare to regualr capacitors in the electronic store?? Also on Novak's message board, they're suggested Low ESR capacitor any difference in use that or not?

Nipple 10-21-2001 09:17 AM

Yes, there is a difference in capacitors.
Those used in R/C has a lower resistance then those normal one find in electric stores.
The ones novak sells have lower resistance.......
But the ones other R/C brand selling may not be......

MattW 10-21-2001 01:56 PM

Not strictly true. The ones we use are simply the lowest impedance that are available. Generally i think that the Panasonic FA series is very popular. I think this is what Novak use. I have been using FA and FC (slightly higher imp) for some time now.

Manticore 10-21-2001 05:09 PM


Originally posted by MattW
Not strictly true. The ones we use are simply the lowest impedance that are available. Generally i think that the Panasonic FA series is very popular. I think this is what Novak use. I have been using FA and FC (slightly higher imp) for some time now.
agree, the ESC manufactorer cannot order an non-existing spec of cap as the minimum quantity is going to kill them.

as a matter of fact, rubycon makes the most variety of specs on cap.

Nipple 10-21-2001 09:50 PM

So how many caps or total 'farah' you all use?

Rog 10-21-2001 09:54 PM

Does anyone know the difference in ratings between the big LRP cap and the Novak cap. My friend and I both run Quantum Competitions. He has the Novak cap and I run the LRP cap. Is there an advantage to running one or the other. Also, the LRP World Option kit comes with 2 caps. A large one and a small one. Is there any benefit to putting them both on?

MattW 10-22-2001 10:15 AM

I wouldn't bother with the small one. It will have larger impedance than the big one. I think the novak one is slightly smaller rated, but i'm not sure.

WHITESTER 10-22-2001 10:29 AM

Can someone please explain what those big caps actually do? In simple terms please...LOL

David Galdo 10-22-2001 10:52 AM

The higher frequency ESC's require a cap to clean up the signal to the motor and receiver. The ESC in turn does less work and should run cooler since the cap also fills the void between frequency changes (open and close of the transistors). I use a 16v 6800uF radio shack cap and also bought a couple extras from Stormer Hobbies.

jcr 10-22-2001 02:14 PM

so is the Radio Shack capacitor is a normal one?

Charlie 10-22-2001 03:52 PM

Power capacitors affect different brands of ESCs differently. The Cyclone line is very reliant on them due to the extremely high rate the mosfets turn on and off. The power capacitor actually catches the ripple current that is created by how hard the Mosfets switch. If not used the ripple current turns into heat and will damage the ESC. Mosfets are the fins that stick out. They are transistors and what carry the power in your ESC.

That's why it is very important to use Low ESR (electro-static-resistance) capacitors. If you use the wrong value the cap will only do part of the work or none at all. And yes it will work for a while. It will slowly deteriorate the performance of the ESC. Most people won’t notice until the ESC is so damaged it slows down. Then they go out and buy a new ESC and think their Cyclone was slow all along. Not the case at all. This is very common. Almost all Cyclones that come back with a different external power cap installed have a shorted internal Polar Drive Cap.

Now I can't speak for the LRP units so lets focus my Info on the Cyclones as power caps affect the LRP units differently.

Once again, we have all of this information post in the tech info section of www.teamnovak.com.

Hope this helps, if you need anything else please don't hesitate to email me.

Charlie 10-22-2001 03:54 PM

I almost forgot. The radio shack capacitors will damage Cyclones and Atoms.

Low ESR caps usually have values of 40 to 50 milliohms.

Charlie 10-22-2001 04:00 PM

Power capacitors affect different brands of ESCs differently. The Cyclone line is very reliant on them due to the extremely high rate the mosfets turn on and off. The power capacitor actually catches the ripple current that is created by how hard the Mosfets switch. If not used the ripple current turns into heat and will damage the ESC. Mosfets are the fins that stick out. They are transistors and what carry the power in your ESC.

That's why it is very important to use Low ESR (electro-static-resistance) capacitors. If you use the wrong value the cap will only do part of the work or none at all. And yes it will work for a while. It will slowly deteriorate the performance of the ESC. Most people won’t notice until the ESC is so damaged it slows down. Then they go out and buy a new ESC and think their Cyclone was slow all along. Not the case at all. This is very common. Almost all Cyclones that come back with a different external power cap installed have a shorted internal Polar Drive Cap.

Now I can't speak for the LRP units so lets focus my Info on the Cyclones as power caps affect the LRP units differently.

Once again, we have all of this information post in the tech info section of www.teamnovak.com.

Hope this helps, if you need anything else please don't hesitate to email me.

David Galdo 10-22-2001 08:08 PM


Originally posted by jcr
so is the Radio Shack capacitor is a normal one?
I had to special order the cap, so pay close attention to what you see in the catalog.


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