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  1. J

    How To tune up the PWM frequency

    After having a nights sleep on it, I am sure that I got counterfeit IRFB4110 MOSFET's. I got them from e-Bay from a China seller who sold 10 at a time for $10.00 shipped. Now that I look at even the 100 unit cost from trusted suppliers like Mouser, Digikey, Jameco I realize that the price was...
  2. J

    How To tune up the PWM frequency

    I agree but I am real sure that before the latest burnout, the cap was not bulging at all. I noticed it right away this time. The cap that has the bulge is on the side that blew a mosfet this time but one on the other side was bad last time. Also the other side is the side that melted the solder...
  3. J

    How To tune up the PWM frequency

    I know it's a dead horse by now but incase anyone is curious.... I found and reconnected the old controller with 36v (it's a 36v controller) and it ran perfect with the motor no heat or anything bad. I only tested it for a few minutes but I did a lot of the running at low throttle where it...
  4. J

    How To tune up the PWM frequency

    I was running wheel off the ground. I don't have anything better than a couple usual DMM's but I just thought of two things. 1) I have a customized golf cart with an ammeter. I can take the shunt from my golf cart and hook it to the scooter with extended wires going back to the golf cart gauge...
  5. J

    How To tune up the PWM frequency

    Well, it crapped out big time. I just put everything back together using 5 batteries instead of my usual 6. I lightly applied the throttle and the wheel started to turn a tiny bit with that usual whine and then the magic smoke was released so I guess the controller blew again. I only applied...
  6. J

    How To tune up the PWM frequency

    That is what I figured about the similar numbers. I actually stopped after realizing none of those components were dead shorted or open. They tested like any transistor device would 3-5kohms here, 10mohms there, basically no leg to any leg below 3-4 kohms or totally open. So I put my meter...
  7. J

    How To tune up the PWM frequency

    The big one in the middle is V12. It is a NP power transistor rated for 100v collector to emitter voltage and 140v collector base voltage. The two small ones are a S8550 and S8050. I'm trying to look at what they are rated at and test them. My testing has been at stock 36 or usually just 24...
  8. J

    How To tune up the PWM frequency

    Very helpful! I will check those things, Thanks!!
  9. J

    How To tune up the PWM frequency

    Since I have modified this controller to be tougher if I can just fix one thing that may be a better thing for me. I am attaching some photos of it. Do you which component the gate driver is? I guess it would be the last transistor in the middle since the 4 smaller ones on each side are the...
  10. J

    How To tune up the PWM frequency

    I think the motor is totally fine. When power is applied it starts right away and spins fast. I also found a nice website that goes through testing windings of brush armature motors and mine tests fine. I plan to drill 4 tiny holes to insert paper clips and hold the brushes so I can reassemble...
  11. J

    How To tune up the PWM frequency

    I have taken the motor apart and I am surprised to say it looks real good inside. The brushes still have plenty of life, there is no heat marks on the brush holders and the armature coils look OK too. I tested impedances between individual segments on the armature looking for a dramatic pattern...
  12. J

    How To tune up the PWM frequency

    I agree, I am hoping it is just that the brushes are worn down and the braided wires have contacted the armature or something that can be fixed with new brushes. If it gets more involved than that I am probably going to scrap or cannibalize this project. I have many hours and a few hundred $$...
  13. J

    How To tune up the PWM frequency

    Update on the controller repair. All seemed to be going well and I even replaced my throttle with one that has a nice battery gauge and a key to turn on and off the scooter so no one runs off with it. The problem is when I finally got it back together the first time I hooked it up it just got...
  14. J

    How To tune up the PWM frequency

    That is a LOT of current. I just run this thing around my neighborhood on concrete streets. Of course It is a little scooter with 8" rims and 12" tires. The rear tire I did upgrade to a moped tire that is larger but I wouldn't take this thing off road or on hills. I may build a bike next since...
  15. J

    How To tune up the PWM frequency

    I decided to order 10 of the MOSFETS. I need 8 but the sale was for 10 and 2 extras can't hurt, especially when it was like $10 total from China. I also ordered upgrades for the Schottky diodes as well. The old diodes were rated for 90v and 16amps (per diode I guess?) The ones I have coming are...
  16. J

    How To tune up the PWM frequency

    I think I should have looked at the specs for the IRFB4110 before asking. That looks perfect for my application and they seem to be dirt cheap from China on e-Bay. I may just have to wait a couple weeks to get them. Another thing I may need to upgrade is the pair of Schottky barrier diodes that...
  17. J

    How To tune up the PWM frequency

    OK, I am looking at Mouser since they seem to have a great elimination filter that you can use to sort through options. The spec sheet of the stock one says Vdss instead of Vds but I guess that would be the same, Mouser refers to the value as "Drain Source Breakdown Voltage" where the Toshiba...
  18. J

    How To tune up the PWM frequency

    I found one shorted TK80E08K3 MOSFET out of the 8. The spec sheet says drain source voltage up to 75v and drain current rating of 80A at or below 175c. I am running six 12V10AH batteries for 72v probably up to 83v unloaded and fully charged, so I am pushing the limits to be sure. I have been out...
  19. J

    How To tune up the PWM frequency

    It seems to have shorted transistors as you suggested. I removed all of them and will see what the better replacements cost.
  20. J

    How To tune up the PWM frequency

    I will do that and post what I find. Thanks.
  21. J

    How To tune up the PWM frequency

    Thanks for the advice. I started to de-solder and check them out of circuit one at a time. Then half way through I thought maybe it was the throttle for some reason. I did notice that of the 4 pairs of transistors the first pair are different than the next three pair of them that are all...
  22. J

    How To tune up the PWM frequency

    I AM NOT TRYING TO THREAD JACK but this seemed to be the conversation to be a part of. I had saved this link while looking for a cure to my loud PWM noise. I am newbie in this site but have already worked on many projects including my current one that I need some help with. I have a Currie...
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