Search found 377 matches

by Buk___
Jan 21, 2018 10:03 am
Forum: Motor Technology
Topic: Mid drive vs Hub Motor for 10000 watt project
Replies: 65
Views: 1315

Re: Mid drive vs Hub Motor for 10000 watt project

johnnyz wrote:
Jan 21, 2018 8:52 am
... soldered 10 gauge solid copper wire with a Tesla style connections ...
What gauge/type of wire did you use for your fusible links?
by Buk___
Jan 21, 2018 1:04 am
Forum: E-Bike Technical
Topic: Anyone know the name of this connector and how to disconnect it?
Replies: 4
Views: 56

Re: Anyone know the name of this connector and how to disconnect it?

Appbeza wrote:
Jan 20, 2018 11:07 pm
https://imgur.com/a/LS2dC

Tried for like 20 minutes to disconnect it. But failed.
Looks vaguely like this one; but that doesn't help you get it apart.
by Buk___
Jan 20, 2018 7:56 am
Forum: Motor Technology
Topic: Cromotor issue... bad sound and lack of power
Replies: 9
Views: 94

Re: Cromotor issue... bad sound and lack of power

@Buk, not sure to be honest, but if you are getting a geared motor so hot that you need ff you are probably going to melt/chew up the nylon cogs, and are probably wildly over amping and overvolting the motor. Or you may have your wiring incorrect. My motor gets too hot to hold my hand on the surfac...
by Buk___
Jan 20, 2018 2:50 am
Forum: Motor Technology
Topic: Cromotor issue... bad sound and lack of power
Replies: 9
Views: 94

Re: Cromotor issue... bad sound and lack of power

brumbrum wrote:
Jan 19, 2018 11:49 am
Yeah , i know theres no clutch, just has sensation like clutch slipping.
Sorry for the apparently dumb question.

I have a geared hub with a clutch, and have been wondering whether it would be compatible with ferrofluid.

I saw mention of "clutch slip" and didn't know a cromotor was a DD.
by Buk___
Jan 19, 2018 11:04 am
Forum: Motor Technology
Topic: Cromotor issue... bad sound and lack of power
Replies: 9
Views: 94

Re: Cromotor issue... bad sound and lack of power

Here’s the low down Cromotor, all good for past 2 years until now. added ferrofluid And hubsink, took for test ride, ok for 15 minutes doing hard start stops up to 120 amp to help heat motor and check temps. All good and then the sound came along. It happens with any sudden amp increase but not so ...
by Buk___
Jan 19, 2018 10:56 am
Forum: E-Bike Technical
Topic: Cute Q100H Autopsy & Modify 2017
Replies: 9
Views: 200

Re: Cute Q100H Autopsy & Modify 2017

What do you want to know? I'd like to know: What the gear ratio is. I've seen numbers ranging from 13.something through 16:1. The dimensions of the planet gears. Tooth counts, PCD and width. Bearing size. (Most of this I could probably derive from an hi res picture.) The diameter and width of the r...
by Buk___
Jan 19, 2018 1:15 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Chalo wrote:
Jan 19, 2018 12:48 am
And yet at the end of the day (quarter-century, to be accurate), the steel frames usually give up first. Go figure.
Nice anecdote!

Now provide some independent verifiable evidence?
by Buk___
Jan 19, 2018 12:33 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Even on my road bike, I look for the biggest sets of stairs to drop or climb, and ride over log piles and aggressive downhill trails,... For that reason my roadbike is cromoly, and the frame has not yet broken... After some more thinking and verifying. Whilst those drops and jumps are almost certai...
by Buk___
Jan 18, 2018 10:50 pm
Forum: E-Bike Technical
Topic: Cute Q100H Autopsy & Modify 2017
Replies: 9
Views: 200

Re: Cute Q100H Autopsy & Modify 2017

Good question - I haven't really looked. I have. I believe I read every thread/post that mentions Q128H on this site. And damn there are a lot of them; even if you exclude those where the mention is in someone sig. But the picture that emerges is very confused, because there seem to have been at le...
by Buk___
Jan 18, 2018 8:53 pm
Forum: E-Bike Technical
Topic: Cute Q100H Autopsy & Modify 2017
Replies: 9
Views: 200

Re: Cute Q100H Autopsy & Modify 2017

Q100H 328 front hub purchased (12/2017). AKM17092301002 / AAD3616A-H / QC-PASS round sticker stating "16 Inches" (white/green) Ratio: 8.139:1 - Gears - / motor 15t / first stage planets 36t / second stage planets 23t / final ring 78t Laminates: 49 stack count - 0.35mm thickness each *** MORE IMAGES...
by Buk___
Jan 18, 2018 8:45 pm
Forum: E-Bike General Discussion
Topic: Active pre-charge/inrush control
Replies: 663
Views: 51399

Re: Active pre-charge/inrush control

An RC circuit can be used for the precharge but it will be very slow depending on the values. My simulation shows a 1m (1,000uf) load capacitor. That 10k will take more than 30 seconds to reach 95 of the 100 volts I have. Charging at a constant current through the mosfets gets to full voltage in 0....
by Buk___
Jan 18, 2018 6:21 pm
Forum: E-Bike General Discussion
Topic: Active pre-charge/inrush control
Replies: 663
Views: 51399

Re: Active pre-charge/inrush control

In some applications it is desirable to have no switch, just connect and disconnect power without inrush or arcing. This can be done using sequential contact mating as I show in this spice simulation. The output mosfets are off at the right times because M2 turns off the gate voltage during contact...
by Buk___
Jan 18, 2018 5:24 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Everyone has a different kind of riding preference. Even on my road bike, I look for the biggest sets of stairs to drop or climb, and ride over log piles and aggressive downhill trails, and it still feels like inadquate training for cyclocross racing. Would you agree that you are an outlier on the ...
by Buk___
Jan 18, 2018 5:00 pm
Forum: E-Bike Non-hub Motor Drives
Topic: My Bafang Ultra Mountain Bike! Frey AM1000
Replies: 278
Views: 12205

Re: My Bafang Ultra Mountain Bike! Frey AM1000

Just received 2 photos of the prototype Frey AM 1000 Fatbike from Ivy Wang. I think it is looking really good, and can't wait to see the production version, and receive pricing and final specifications. I have particularly asked them to manufacture Front And Rear Fenders as a factory option.. I thi...
by Buk___
Jan 18, 2018 4:51 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

liveforphysics wrote:
Jan 18, 2018 4:50 pm
My bike is 18.5lbs fully assembled with cyclocross tires. I don't know the bare frame weight.
I read bad info. I've corrected my mistake above.
by Buk___
Jan 18, 2018 4:32 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

It's a 2002 Lemond Zurich using Reynolds 853 (the predecessor of the amazing 953) running a mix of dura-ace components with a cable pull ratio modified modern XTR rear derailleur (for it's auto-chain tensioner function that is awesome for avoiding chain drama on big impacts). The tubes are butted t...
by Buk___
Jan 18, 2018 4:09 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Even on my road bike, I look for the biggest sets of stairs to drop or climb, and ride over log piles and aggressive downhill trails, and it still feels like inadquate training for cyclocross racing. For that reason my roadbike is cromoly, and the frame has not yet broken (though I go through wheel...
by Buk___
Jan 18, 2018 2:53 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I've personally never felt like pedaling related forces were significant compared to riding impact related forces. Right. Potholes and even little bumps can have much higher instantaneous peaks (even if the durations are short), Still missing the point. You don't generally ride from one pothole to ...
by Buk___
Jan 18, 2018 2:46 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

[...]well below the 480Mpa fatigue limit of normalised ChroMoly. That's close to the yield stress of normalized 4130, so the fatigue limit would be not much more than half that. Wrong again. Fatigue limit is usually roughly half of the ultimate tensile strength , not the yield strength. Here the wo...
by Buk___
Jan 18, 2018 6:08 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I've personally never felt like pedaling related forces were significant compared to riding impact related forces. The point is, it isn't the big impact that cause fatigue failure. They can exacerbate it, and if they're big enough to go over the yield point, bend or even snap. But fatigue is repeti...
by Buk___
Jan 18, 2018 3:16 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

And there are two reasons I can't give a definitive answer to that question. First is, even though a frame can be characterized by stress analysis, the stresses it will see out in the world are not easy to characterize or quantify. What are normal forces for one rider are abnormal for another. So w...
by Buk___
Jan 17, 2018 11:58 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

If a steel structure is design such that its expected maximum loading + some margin is less than the fatigue limit, it will not fatigue . Ever. (for all practical purposes. To the nearest approximation, bike frames are not built that heavy. Ever. Update: Rephrased ambiguous question. You are saying...
by Buk___
Jan 17, 2018 9:15 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Chalo wrote:
Jan 17, 2018 8:51 pm
Weight for weight,
I said "same specification", not "same weight". For an engineering, you do not seem to read well.
by Buk___
Jan 17, 2018 6:45 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

e-beach wrote:
Jan 17, 2018 6:10 pm
... screw ...
Screws cut threads, and they are stress risers.

Carefully drilled 3.2mm holes and pop-rivets don't. It's why they use pop-rivets to hold aluminium planes together.
by Buk___
Jan 17, 2018 6:42 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 92
Views: 1207

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I was in engineering development and machining for about 15 years-- culminating in almost 6 years as the fifth employee on the starting team of what is now a high profile private space program. My title there was "technical generalist". Then if you'd read either of the links above -- the non-wikipe...