Search found 3233 matches

by Lebowski
Oct 08 2019 1:19pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Lebowski, can you also explain a little more about 141 percent T? Basically you have the flux from the permanent magenets (100% T) and the flux from the coils. Lets say the flux from the coils at max phase current is also 100% T. These two fluxes are at a 90 degree angle of each other (for max torq...
by Lebowski
Oct 08 2019 12:29pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

I still think where the coils are wound the area should be minimal (based on flux and what material can hande, dont forget 141%), and round ! could you please explain a little why it is so important for coils to be round? in most radial flux motors i've seen the coils have almost rectangular shape ...
by Lebowski
Oct 06 2019 9:59am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

I still think where the coils are wound the area should be minimal (based on flux and what material can hande, dont forget 141%), and round !
by Lebowski
Oct 01 2019 1:50pm
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1794
Views: 202757

Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Why build this boost converter and not just use field weakening ?

Arber, you want to measure after the boost converter, so at the power stages.
by Lebowski
Oct 01 2019 11:30am
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1794
Views: 202757

Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Arlo1 wrote:
Oct 01 2019 11:12am
Amber this needs to be isolated!

That's why I posted the circuit!
Depends on how far reaching you want your power stage blowup to be :wink:

Arber, i dont really understand the distinction beween the 400 and 650, but the controller ic needs to see the power stage supply voltage.
by Lebowski
Sep 30 2019 12:01pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Still... your magnets make a certain flux. With the coil current flux rises to 1.41 times this. For this flux, keeping saturation in mind, you need a certain metal area. The smallest circumvence (wire length) your get for a circular area..
by Lebowski
Sep 30 2019 7:35am
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1794
Views: 202757

Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Arber, I think you misunderstand. When you want to deal with a 400 V battery you need to divide this voltage down by a factor 80. The controller IC will then work correctly for battery voltages between 200 and 400V, as these map in the 2.5 - 5 V range. You should not map 0 - 400V on 2.5 - 5V ! You'r...
by Lebowski
Sep 29 2019 2:53pm
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1794
Views: 202757

Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

I use just a resistor, but Arlo1 haf a good isolating opamp in his high power design.

Yes it is programmed only for a range of 2, as that should cover a battery between empty and full ...? It needs to do a 1/x internally, the factor 2 is chosen to limit the output range of the 1/x calculation...
by Lebowski
Sep 20 2019 1:03am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Yeah, rings embedded in an insulating rotor repelled from high frequency coils. Higher frequency than rotation for efficient repulsion, but with modulated intensity that rotates in much the normal slow way. Except pushing rather than pulling. Starting to sound like a squirel cage induction machine...
by Lebowski
Sep 19 2019 1:44pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Just my take on motors... i look at them as voltage generators. Motor power comes from volt and current, so the motor should make as much volts as possible and conduct current as efficiently as possible. For me thinking in terms of electromagnets is not where its at...
by Lebowski
Sep 19 2019 12:21pm
Forum: Battery Technology
Topic: Tesla/Dahn Lithium-NMC532/AG chemistry
Replies: 19
Views: 739

Re: Tesla/Dahn Lithium-NMC532/AG chemistry

My point is not about this specific car. My point is that everyone is building supercars with awesome power and accelleration, but what is needed is a reasonable car for the masses at low cost. I for one am tired of seeing all these fat cat playboy cars with accelleration this and a 40" screen that ...
by Lebowski
Sep 19 2019 11:55am
Forum: Battery Technology
Topic: Tesla/Dahn Lithium-NMC532/AG chemistry
Replies: 19
Views: 739

Re: Tesla/Dahn Lithium-NMC532/AG chemistry

Pffff rediculous. Why not make a cheap eurobox with 70kW (peak power) and 500km range ? Much more usefull and effective for getting people in electric cars. All this high tech gadgetry and high performance just makes the cars too expensive and out of reach for most people. because nobody is going t...
by Lebowski
Sep 19 2019 11:23am
Forum: Battery Technology
Topic: Tesla/Dahn Lithium-NMC532/AG chemistry
Replies: 19
Views: 739

Re: Tesla/Dahn Lithium-NMC532/AG chemistry

.......i just hope that the new generation S has the model 3 cells when they start selling the plaid 3 motor kit. putting down nearly 10.000nm of torques into some poor tires is going to be awesome....... 10,000Nm ! :shock: ....that would truely be more than Awesome ! :lol: Pffff rediculous. Why no...
by Lebowski
Sep 18 2019 2:30pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

The last picture you show : Hm. I would want the moving rotor to generate air flow over the coils...
by Lebowski
Sep 18 2019 1:14am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Yeah but the point of the steel is to 'focus and compress' the magnetic field so that the wiring length (resistance) is reduced. How is that achieved here ?
by Lebowski
Sep 17 2019 1:37am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

In a coreless motor the torque comes from the Lorentz force: https://en.wikipedia.org/wiki/Lorentz_force F = B * I * l with B the magnetic field ( https://www.kjmagnetics.com/gap.calculator.asp ). For two round 25mm magnets, 7mm thick, grade N42, spaced 7 mm, no yoke, roughly 4000 gauss average. (or...
by Lebowski
Sep 15 2019 4:33am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Was it your intension that the 25mm PM's fit within the center, or 'eye' of the 40mm coils? I assume thats to take advantage of the radial winds on a circular coil? I'm just curious as to why not a more compact, (hole-less?), coil. I'm trying to understand the action of a coreless coil on the PM. M...
by Lebowski
Sep 14 2019 2:05am
Forum: E-Bike General Discussion
Topic: Fast Ebike for a tough commute
Replies: 56
Views: 1979

Re: Fast Ebike for a tough commute

How about something different than a normal bike ? Maybe a tadpole trike ? Low to the ground, so maybe less battery capacity necessary to do the distance ? Probably also more stable at high speed and capable of carrying the battery weight ?
by Lebowski
Sep 14 2019 1:20am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

My motors were (mechanical output) 750W at 900 rpm for v1 and 3000W at 1500rpm for v2. You can calculate the torque (its saturday morning now, reading the news with coffee and croissant, sitting in the sun, not in the mood for calculations) For my motors the limiting factor is the balancing of the r...
by Lebowski
Sep 09 2019 6:02am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

I would calculate if the pointy of your stator makes sense. It increases backemf as there is more circumvented flux, but does it outweigh the extra wiring length (resistance)? This can be calculated and optimised ! Also, the prupose of the stator metal is to reduce wiring length. The metal takes the...
by Lebowski
Sep 07 2019 5:51am
Forum: Motor Technology
Topic: Switched reluctance motors
Replies: 11
Views: 437

Re: Switched reluctance motors

One more remark about SR motors, For PMSM (what we have with the magnets), Torque proportional with I, losses with I^2, So at half of max torque, I=0.5*Imax, losses proportinal to 0.25*Imax^2 For SR, Torque and losses both proportional to I^2 So at half of max torque, I=0.71*Imax, losses prop to 0.5...
by Lebowski
Sep 06 2019 3:49pm
Forum: Motor Technology
Topic: Switched reluctance motors
Replies: 11
Views: 437

Re: Switched reluctance motors

SR is the top pick from an economic/business standpoint not an engineering one. but people not in the know that look to others for guidance will think "well, if Tesla is doing it, it must be good." just like they do with Tesla's sub-optimal engineering choice of 18650 which had more to do with not ...
by Lebowski
Sep 01 2019 3:52am
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 575
Views: 88136

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15

Man, 250c, they'll be empty in 14 seconds !
by Lebowski
Aug 24 2019 12:46am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32916

Re: APL's DIY axial-flux motor

Next step is a proper controller :D