Which FET's on CC 25?

[Dukester]

I got a CC25 in a bag of stuff that has melted plastic over one FET. I didn't realize it has the melted plastic and when I was testing it seemed to work fine up for maybe 20 to 30 seconds. Then the FET heated up and it started stuttering. Repeating the test showed the same thing. It will repeatedly start ok and run at low throttle, then after a bit the FET heats up and it starts stuttering.

Anyway, the short question is what FETs are used in the CC esc's? I know swapping the FET may not be the fix, but I'm interested to try anyway.

Thanks,
Duke

[vpersiani]

Hi

I have just had a CC-60 fail on me today.
However not all FETs are burned and I can still read on the good ones IR 409H and IR 412H. I am pretty sure thoses are International Rectifier FETs but I have been unable to find datasheet and/or supply for thoses.


Vincent

[thanhTran]

Maybe you can find the FET you need from the label marking guideline in the following data sheet (on page 8):

http://www.irf.com/product-info/datasheets/data/irf7862pbf.pdf

Digikey search is quite nice. It may give you what you need.

3 years ago, I replaced FET's of an Align 35A ESC with some IRF hex fets. The original FET's were Vishay FET's, I think. They are still working fine now.

Thanh

[JohnMuchow]

Duke,
The bottom number is the part number (see page 8 of Thanh's link). I can't read them in your photo though. :)

John

[Dukester]

Duke,
The bottom number is the part number (see page 8 of Thanh's link). I can't read them in your photo though. :)

John

John,

My original post is a bit dated. I ordered the FETs from digikey and with a little careful soldering got my ESC fixed. I'm not 100% comfortable with it, so even though I've tested mine up to 20 amps, I only use it on setups drawing 10 amps or less, but it seems to work fine.

I should just send it in to CC for repair, but since it's working.....

Duke

[JohnMuchow]

Arrgghhh...sorry Duke. I meant to address my post to Vincent. :o

[vpersiani]

Wonderful! I knew I would get instant solution from the RCG comunity!
Thanks guys :)

Not sure why but I would have bet that part number was the top figure not the bottom one!

BTW anybody knows why IR7862 is marked 7832 :confused:
Just to make things more complicated?

Vincent

[Dukester]

BTW anybody knows why IR7862 is marked 7832 :confused:

If you're talking about the product sheet, it has a note that says it's showing the 7832 pic as an example.

Duke

[vpersiani]

OK then those are IRF7832.
See zoomed picture.

Vincent

[Dukester]

This one then?

Data sheet:
http://www.irf.com/product-info/datasheets/data/irf7832.pdf

Digikey part:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=IRF7832CT-ND

Double check that this is the right one, they show two 7832s sold individually with slightly different designations, but they appear to have the same specs on the short list.

Also, unless you have the right setup, it's a pain to solder the new one on.

Duke

[jackerbes]

"..unless you have the right setup, it's a pain to solder the new one on..."

And I think that might be a multiple layer board too which complicates things further in that the layers might be damaged or shorted, right?

I had a three or four year old Phoenix 25 go up in flame and smoke a while back while I was bench testing a system in a new plane. It only "cooked off" one of the IC's but the flash melted the solder and all three of the motor leads fell off. The Watt's Up reported a 62.5 Amp peak.

I sent that one off with a $25 check and got and brand new one back that is an improved design, I was happy with that deal.

Jack

[Dukester]

I need to go ahead and do the same with mine. It sucks not being able to trust it for what its rated for.

[jackerbes]

I'm not sure if I overloaded the Phoenix 25 that I burned up or if it died of old age.

It was pulling 12-13 Amps from a charged and rested 4S A123 pack (the pack was right around 12V when the ESC fried) and it was on a system with a Berg 4L receiver and four TP ST-90 micro servos which were centered and resting.

I had been running the motor at various speeds up and down, had seen a momentary peak of 22-23 Amps, then settled down to a 12-13 Amp mid throttle run. After 15-20 seconds at the 12-13 Amp reading the ESC flashed, smoked, and it was over.

I've been using the A123 packs one "S" higher than a regular LiPo because of their lower starting voltages. So even though the P25 is only rated for 3S or 12.6V with the BEC in use, I don't think was overloading it at the battery side.

The IC that burned up on my PHX-25 was the one that is seen burned up in Vincent's photo above. I think just one the FET burned and all three of the motor leads unsoldered and fell off when that happened.

I got a new replacment back from CC in about 8-10 days and was very happy about that. I put the new PHX-25 at the same settings with the Castle Link, put it in the same system, with the same battery, and gently brought it up to speed as I held it between my fingers. At about 13 Amps it was so hot that I had to release it (over 130F) . I call CC and talked to a tech about it and that, and reading the CC FAQ, was where I gained a better appreciation for the frailties of the linear BECs.

I had a HXT UBEC laying around, I put that in the system, repeated the test and found the PHX-25 just warm (100-110F?) to the touch at the same 13 Amp load. So I'm now a UBEC convert of sorts and I'll use the finger testing as the criteria for using them. If I cannot hold on to it at cruising or typical sustained flying load it gets a UBEC.

Jack