Search found 51 matches

by thorlancaster328
Jul 21 2018 8:04pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

Its been a while. I arrived home from my camping trip and got to work on the ESC the next day. It wasn't running right I found a loose connection and "fixed" the problem. I twisted a potentiometer hooked up to the throttle pins, and the motor started with a loud gzgzsgzgzgz-wrrrrrRRR-wrrRRR-wRRrrrrr...
by thorlancaster328
Jul 05 2018 7:25pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

About a week ago, the FETs arrived. I soldered them in, and... It didn't work! I did a little probing and one of the 3 NCP5181 gate driver chips was blown. I ordered some more, and they arrived a few days ago. I installed them and tested the board against a RC brushless motor hooked up to a propelle...
by thorlancaster328
Jun 30 2018 9:12pm
Forum: Motor Technology
Topic: Sensorless at standstill, development updates and status
Replies: 78
Views: 6910

Re: Sensorless at standstill, development updates and status

It's almost like magic, being able to do full torque with no hall sensors! How are you doing it? My guess is that you feed a electrical pulse into a coil and measure the di/dt and thus the inductance of each phase. Once you know the inductance, you can calculate where the magnets are in relation to ...
by thorlancaster328
Jun 23 2018 10:09pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

I've completed the back side of board attempt #2 and here is the layout of the power section. The power wires are on the right, and the three phase wires are sticking straight up. The FETs will be on the other side, with the leads and all associated wiring as short as possible. Based on an online re...
by thorlancaster328
Jun 17 2018 2:22pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

What do you mean by topology?

In my old ESC, the Vcc and ground traces snaked around quite a bit. In this version, the Vcc and ground traces are straight and reinforced by heavy gauge wire.
by thorlancaster328
Jun 16 2018 11:23pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

So what do you think the main problem is with my design? When It burned the first time, I was using 60mΩ P-channel FETs. WAY too high. For the powerstage of my new controller, I have pretty much copied Lebowski's power stage. I have looked at several commercial ESC schematics and they all are nearly...
by thorlancaster328
Jun 16 2018 2:59pm
Forum: Motor Technology
Topic: Anyone have any tips on rewinding MXUS 3k?
Replies: 12
Views: 818

Re: Anyone have any tips on rewinding MXUS 3k?

It seems kind of odd that only one phase was burned. In other burned motors I've seen, all three were charred and black from sustained overheating. After you rewind your motor and add a thermistor (highly recommended), make sure that your controller is not "single phasing" the motor. Single phasing ...
by thorlancaster328
Jun 15 2018 10:10pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

For insulating the heatsink, I have decided on a layer of heavy duty packing tape. I placed the heatsink in boiling water and tried to scratch the tape with the butter knife. The tape stayed intact. Next, I tried melting it with a lighter. The tape stayed cool and the heatsink got a little warm. Sin...
by thorlancaster328
Jun 14 2018 10:09pm
Forum: Motor Technology
Topic: big motor small controller
Replies: 5
Views: 675

Re: big motor small controller

For maximum power, the controller and motor should be rated about the same. If your motor is rated too low, you'll likely fry it. If your ESC is rated too low, you won't have any power and may fry it too. 27kv is pretty high for an eBike motor. You'll want a decent controller. I'd recommend a 50 amp...
by thorlancaster328
Jun 14 2018 10:05pm
Forum: Motor Technology
Topic: Anyone have any tips on rewinding MXUS 3k?
Replies: 12
Views: 818

Re: How easy is it to repair burnt windings?

Your motors are most likely toast. I woudn't try the varnish trick because it would be at most a temporary fix and the motor could easily short out again, blowing your controller. If you elect to rewind the motor, you'll have to pull out the old wire and make a chart of how it was wound. Next, you w...
by thorlancaster328
Jun 14 2018 9:32pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

I have decided on the NCP5181 driver, the ones recommended by the Lebowski controller project. My controller will be a 12-FET one, with 8mΩ IRF3205 MOSFETs. It should be able to do 50-60 amps continuous with a heatsink and a fan. Additionally, this time, I will be cooling the FETs the right way. The...
by thorlancaster328
Jun 13 2018 6:22pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

I have done some research into N-channel H-bridge topology and have decided to go that route instead of farting around with P-channel FETs. Right now I'm considering the LT1160 gate driver IC from Linear Technologies. Does anyone see any issues with using that particular chip? It's rated up to 75v. ...
by thorlancaster328
Jun 13 2018 5:29pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

I soldered in all new FETs and powered up the board. It worked great driving a small brushless motor from 12v. Next, I hooked it up to my bike with a 30A fuse. It can handle easily 50, right?? About 10 feet into an easy acceleration, I heard a loud hissing sound from the back of the controller. I qu...
by thorlancaster328
Jun 10 2018 10:43pm
Forum: Battery Technology
Topic: My 38kw, 138v, 3.8kwh LTO Battery
Replies: 26
Views: 2274

Re: My 38kw, 138v, 3.8kwh LTO Battery

I thought my 1kW battery was huge. That's one beast of a battery :) Have you considered how you are going to charge that thing? Many of them can be charged at 5C without diminishing the battery life much. Looks like you'll be able to fill up almost as fast as those gas guzzlers, given the right (30k...
by thorlancaster328
Jun 07 2018 11:26pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

At the time of the incident, the battery that I was using was 25 volts. The resistance of the motor was 200mΩ, the battery was 35mΩ, and both FETs 65mΩ. 25 volts into 300mΩ gives 83 peak amps. Half that into a 60mΩ FET gives a whopping 103 watts. Bang! I never thought that surges could be that bad. ...
by thorlancaster328
Jun 07 2018 8:01pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

The regulator arrived today, and I took the thing out for a test run. The first time I applied a serious amount of power (accelerating on grass), I heard a pop and smoke started pouring out of my rear end. I quickly pulled the battery and inspected the damage. One MOSFET was burnt and charred, and t...
by thorlancaster328
May 31 2018 7:11am
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

When the regulator arrives, I'll post a schematic and code, along with a short tutorial.
by thorlancaster328
May 30 2018 10:47pm
Forum: E-Bike Technical
Topic: Reusing a Bionx battery (and fooling it into turning on - and staying on)
Replies: 1
Views: 289

Re: Reusing a Bionx battery (and fooling it into turning on - and staying on)

There are two ways to do this: 1. Reverse engineer the protocol by hooking a scope up to each of the pins and seeing what signal is used to wake the pack (I wouldn't be too surprised if it's a 2-way encrypted handshake, given how Bionx blocks 3rd party components. In this case, no amount of scope pr...
by thorlancaster328
May 30 2018 10:02pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

Thanks for the info on switching losses, Fechter. Given that the frequency is low for the MOSFETs (22khz), I shouldn't need to derate the controller much, if at all. The controller now has a fan and a soon-to-be-waterproofed enclosure for protection and cooling. The "snail blower" puts out a LOT of ...
by thorlancaster328
May 29 2018 2:30pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

I finished up the controller today and decided it was time for a test. At 13.5 amps, it registered only a 10°C increase from ambient. Given that I can tolerate roughly an 80°C increase from ambient (100°C thermal limit), the controller can run 8x hotter. As heating is proportional to the square of t...
by thorlancaster328
May 29 2018 2:13pm
Forum: Items for Sale - New
Topic: Nucular electronics - complete kit for ev! [beta]
Replies: 792
Views: 66776

Re: Nucular controller

What kind of FETs do you use? I assume they're all N-channel. 200 amps for 30 seconds sounds very nice, even across 2 FETs.

And for the over-regen protection, I'd just put a thermistor next to the FETs and dial back the regen if the FETs got too hot.
by thorlancaster328
May 27 2018 7:00pm
Forum: Motor Technology
Topic: Why my Ebike controller always broke
Replies: 4
Views: 486

Re: Why my Ebike controller always broke

Some controllers are overrated, but any 1500W controller should stand up just fine to the task of driving an undamaged 350 watt motor. I would recommend that you do an ohm meter test on your motor. If you do not already have one, go to the hardware store and buy a digital multimeter. I suspect that ...
by thorlancaster328
May 27 2018 10:25am
Forum: Motor Technology
Topic: Why my Ebike controller always broke
Replies: 4
Views: 486

Re: Why my Ebike controller always broke

Does your eBike controller have overheating protection? Repeated failure after 5 minutes of riding probably indicates a thermal problem. Another possible reason could be a shorted phase winding. Take an ohm meter and measure between each pair of wires. If they differ by more than about 15%, you prob...
by thorlancaster328
May 26 2018 11:58pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

Here is the math for the power dissipation at 20 amps: Low side (N Channel): 4.9 mΩ * 20A * 20A = 1.96W through 1 FET = 1.96 watts per FET*1/3 duty cycle = 0.65 watts average per FET. High side (P channel, 30mΩ because 2 FETs are paralleled) 30 mΩ * 20A * 20A = 12 watts through 2 FETs = 6 watts per ...
by thorlancaster328
May 26 2018 11:13pm
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2987

Re: Building a 100% DIY ESC for motors

Thank you everyone for the advice. I've heard of the high-side N-channel driver chips, but I wanted to do this the 100% DIY way. I already had ~90% of the required parts in my storage drawers (everything except the FETs). In hindsight, I probably should have used just N-channel FETs and a driver IC....