upgraded FETs - Page 17

eetoi · #**241** 03-21-2004, 03:12 PM

I've ordered MY fets, I'm so excited...(One of them was backordered till April, I guess these things are in demand!) I tried a motor similar to the plasma dash, but made by auldey (only $1!) and when I put it in with a tamiya plastic gear and such, it seemed very weak, and took a while to get to top rpms(even under no load, I tried it out of the car), I'm assuming that after this mod, it will scream and accelerate better (It was uncontrollably fast in my mini4wd car, it BROKE a few parts of the car, I guess that's what digi-propo is for)... Am I right? And there's this OTHER motor, my cousin rewound (he's a mini4wd racer from the Philippines), and it took even longer to rev up.

aperson · #**242** 03-21-2004, 07:18 PM

i dont think this was asked yet but is this still proportional?

geofroley · #**243** 03-21-2004, 08:15 PM

Nuero, in your pic, does one wire go to one battery case, and the other go to the other one?

Rez · #**244** 03-22-2004, 07:14 AM

Quote:

Originally posted by aperson
i dont think this was asked yet but is this still proportional?

Yes, it was asked, and it is.

aperson · #**245** 03-22-2004, 07:17 PM

oh sorry. i must have missed it.

meteoraclown · #**246** 03-28-2004, 08:10 PM

ok another question. where did you get the circuit board at? can i get them at a computer show or can i go retailers and get them?
almost there with the money. yay. i ha d the money before but had to pay back some money i borrowed.

eetoi · #**247** 03-28-2004, 08:56 PM

Quote:

Originally posted by meteoraclown
ok another question. where did you get the circuit board at? can i get them at a computer show or can i go retailers and get them?
almost there with the money. yay. i ha d the money before but had to pay back some money i borrowed.

They sell circuit boards at Radioshack. Wow, they sell a lot of stuff at radioshack. Off topic, but, after I got my xmod, I started going to Radioshack a lot more often...

meteoraclown · #**248** 03-29-2004, 04:05 PM

ehh i don't think my RS is any good. the guy behind the counter didn't even know where the stuff was behind the counter on the wall. He didn't even know the difference between the S1 and S2 motors. i'lljustwait till i can go to the store where i got my car at.

aperson · #**249** 03-29-2004, 05:37 PM

eetoi, i'm only allowed to go to RS once a week since i got my XMOD. almost every night.

eetoi · #**250** 03-29-2004, 07:55 PM

aperson, that's about how often I get to go, wait, no, it's been like twice or thrice a week... now, why does it say; once a week, then, almost every night?

aperson · #**251** 03-29-2004, 08:27 PM

sorry i meant to say that i used to go almost every night.

ph2t · #**252** 04-15-2004, 09:36 PM

time to raise the bar on the techo side ..........

Neuro, first off: great work dude. It's great to see a fellow techo doing his thing and doing it well.

Some points:

Have you investigated using mosfet driver IC's? They pretty much allow you to take a low votage signal and drive this at a full 10V to be able to turn on the fets properly. I know you mentioned that you are using logic level fets (Vgs = 4.5V) but as you've prolly realised the normal power fets that offer the ultra low Rds(on) values (ie, < 0.01 ohms) need the higher 10V gate drive to work properly.

Also, mosfets have a capacitive property to them that inhibits the drive on the gate pin for a very small about of time. Using a mosfet driver chip you can charge this "gate capacitane" really quickly and get the mosfet into it's "enhancement state" easliy.

I say this because I'm currently designing an external turbo for my mini-z and I want something that meets the following (high) expectations:

-Ultra low Rds(on)
-Good power disipation (D2PAK? SO-8?)(TO-220 is too big, lol)
-Easy to install (idealy run of the motor terminals)
-Ability to drive on 5, 6 cells.
-possible incorporate mosfet driver and 10V DCDC convertor cct.

I know this doesn't help you that much but as a fellow devotee to the black arts I thought I'd share......

greets from downunder. If you're on MSN, look me up ph2t@prahranpianos.com

ph2t.

Jshwaa · #**253** 04-17-2004, 10:54 PM

Here's my version of the ESC using TO-220 power FET's. 74A, 200W means I can use whatever motor and not even worry about it. The FET's are lovin' it.

_INDY_1979 · #**254** 04-29-2004, 01:34 PM

wow jshwaa thats hardcore, is that a total replacement for the stock ESC, how's it working for you so far?

Jshwaa · #**255** 04-29-2004, 01:51 PM

The one in the above picture is funtional at best, but cannot carry the current that it was intended. There's a small design flaw in that the FET's are not properly 'driven' and thus present too much of a load to high current, thus making them heat up and derate, then slowly start to burn up. I never let them get that far before I disconnect power, however. I just know what'd happen if I were to wire this thing in with a hot motor and full-throttle it for a minute. Poof!!

I haven't given up, though. As a matter of fact, I have parts coming by Monday(5/3) at the latest. I'm going to address the driving issue and slim down the circuit a little. Hopefully it'll be ready for video by next weekend(5/8).