Search found 808 matches

by major
Nov 25 2020 8:36pm
Forum: Battery Technology
Topic: Milwaukee battery out of balance
Replies: 8
Views: 756

Re: Milwaukee battery out of balance

I've had good luck with Milwaukee. But had a cell fail on Craftsman C3-19.2V Li. I replaced the bad cell, just the one out of five. Used solder. As long as I had it open with tools handy, I installed a JST plug. Even though new cell is a mismatch battery seems to function o.k. I have it plugged into...
by major
Nov 20 2020 5:21pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

OK I can see the open and closed loops. So are we talking 3 phase induction coil, and any ferrous material at it's center is affected? I can't quite envision your field yet, but I still think that the affect would diminish with distance. ... Hi APL, Without straying too far off-topic, envision a cl...
by major
Nov 19 2020 2:13am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

Shouldn't be much different from any other axial coil arrangement, still a circle of 3 phase coils around some steel or aluminum parts, right? Maybe I'm missing the point. The difference from most other axial coil arrangements is they use closed loop coils whereas this guy has essentially "ope...
by major
Nov 17 2020 10:01pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

If you make the winding basically a big circle around the axle, wont you induce eddy currents and losses in the axle iron ? Maybe. I don't see how it wouldn't, but it depends on distance as to how much. I don't think distance matters. However, if that "circle" around the steel carries a b...
by major
Nov 15 2020 10:39pm
Forum: Motor Technology
Topic: Need help : number of pole pairs
Replies: 5
Views: 523

Re: Need help : number of pole pairs

Easy way to find out number of coils in electric motor is to connect classic voltmeter to its power lines and slowly turn wheel by 360 degrees counting numbers of movement of the needle (pointer). Just verified that way my 205 50H V3 QS Motor, has 16 coils. Voltmeter was set to 3V DC... Hi Maciek, ...
by major
Nov 09 2020 6:46pm
Forum: Motor Technology
Topic: Reversing a Trolling Motor
Replies: 5
Views: 487

Re: Reversing a Trolling Motor

Hwy89 - Reversing the polarity is not useful for long term usage if the brushes are not near the neutral plane. Otherwise there is excessive wear on the brushes and commutator when the current is not at a minimum. Major - Thanks, that seems to be the case based on the no load measurements. It just ...
by major
Nov 08 2020 8:14am
Forum: Motor Technology
Topic: Reversing a Trolling Motor
Replies: 5
Views: 487

Re: Reversing a Trolling Motor

Hi, For trolling, the standard design of the 2-pole ceramic PM motor aligns the brushes directly with the center line of the magnetic pole. This puts the armature field in quadrature with the stator field. Magnetic neutral = mechanical neutral. No shift (advance) is used. If direction of rotation is...
by major
Nov 02 2020 10:32am
Forum: Battery Technology
Topic: DC Load test large battery packs. Rheostat?
Replies: 13
Views: 777

Re: DC Load test large battery packs. Rheostat?

Hi, Take a look at my load bank. 14cell3CtestResistor.jpg Rack houses 24 locomotive braking resistors, 1.2kW each. Can easily series parallel reconnect for desired load. Most I've done was 200V, 400A. Gray box on side is 1000A contactor with homebuilt IGBT buck converter. Resistors were surplus buy ...
by major
Oct 07 2020 4:47pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

Hi APL, Actually laminations are used to minimize Eddy currents, not hysteresis loss. Hysteresis is dependent on metallurgy, not shape. Eddies depend on the path and resistance of the path as well as the path orientation to the changing magnetic flux. Eddy current and hysteresis losses are two distr...
by major
Oct 07 2020 1:01pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

Screenshot_20201007-141034.png
Screenshot_20201007-141034.png (417.06 KiB) Viewed 246 times
Hopefully that is a link to a download of paper about the subject motor. Looks interesting. Complex/complicated for ? gains.

Regards,

major

edit: link didn't work so here's a screenshot. Hope that helps.
by major
Aug 19 2020 12:51pm
Forum: Motor Technology
Topic: ME1003 Motor
Replies: 6
Views: 348

Re: ME1003 Motor

Cool (no pun intended). How do you measure winding temperature? You know, most times brushes are set to neutral on PM motors. Without steel pole faces near the armature, the armature field distorts the main field much less. The same thing would be true for a PM generator. But whatever works for you....
by major
Jul 28 2020 11:40pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

<snip> (Cross section is a bit of a mess, but I've learned a lot since then.) https://endless-sphere.com/forums/download/file.php?id=276879 V2 crosection..jpg Hi APL, Too bad you're having difficulty. Often one pays close attention to the electromagnetic assembly overlooking basic machine design. I...
by major
Jun 29 2020 12:10pm
Forum: Electric Watercraft
Topic: What is this Boat?
Replies: 16
Views: 630

Re: What is this Boat?

Looks nice and my guess is it would work with series connected pack. But for reliability, I've used multiple units for many years without a single issue, my money would go to Minn Kota.
Screenshot_20200629-130208.png
Minn Kota charger
Screenshot_20200629-130208.png (265.27 KiB) Viewed 412 times
major
by major
Jun 29 2020 10:10am
Forum: Electric Watercraft
Topic: What is this Boat?
Replies: 16
Views: 630

Re: What is this Boat?

BTW, if bilge pump runs off 12V, 2 of the 6V batteries, you'll have uneven discharge across the 4 pack. Then issues using a 24V charger. I'd consider getting a Minn Kota 2 by 12V marine charger. It'll at least equalize to 12V. I've never seen a 4 by 6V charger.
major
by major
Jun 29 2020 10:00am
Forum: Electric Watercraft
Topic: What is this Boat?
Replies: 16
Views: 630

Re: What is this Boat?

My guess is it is a PM (permanent magnet) motor. Maybe a Honeywell or Pacific Scientific, maybe Peerless, doesn't look like an Ohio Electric. So likely ceramic magnet stator, guessing 2-pole, wound rotor. Brushes and commutator prone to overheat on overload or long runs on hot days. 2-speed: either ...
by major
Jun 24 2020 7:55pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

... To avoid saturation, I think you have the option of making the tooth longer. APL, Saturation starts limiting at higher flux density, in units of Tesla, which is equivalent to Webers per square meter. So it is the cross sectional area normal to the flux path. A longer tooth means increased magne...
by major
Jun 23 2020 3:18pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

It brings me back to a question that has been nagging me for a while,.. seeing cores like this. I've always wondered, just how important the 'center' of the core is to axial motor operation. It's really the CSA, cross sectional area, which is important to keep the flux density below saturation of t...
by major
Jun 22 2020 1:34pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

The two coil sides cancel. Need area between the conductors carrying current in opposite directions.
major
{edit}
The method shown nets zero current per slot.
by major
Jun 22 2020 11:34am
Forum: Items for Sale - Used
Topic: Deal on motors/wheels
Replies: 51
Views: 3359

Re: Deal on motors/wheels

I got my order last week. One of the motor leads was cut off so near the axle (like 1/4") it will be impossible to splice. So I popped it open. It's a gear drive so it slipped out of the ring gear. Photo attached.
IMG_20200620_145737546.jpg
Bike wheel motor
IMG_20200620_145737546.jpg (324.09 KiB) Viewed 601 times
by major
Jun 09 2020 8:50am
Forum: Items for Sale - Used
Topic: Deal on motors/wheels
Replies: 51
Views: 3359

Re: Deal on motors/wheels

Thanks.
Regards,
major
by major
Jun 08 2020 7:23pm
Forum: Items for Sale - Used
Topic: Deal on motors/wheels
Replies: 51
Views: 3359

Re: Deal on motors/wheels

Hi all,
A box with 2 wheel-motors was delivered today per my order. Brake calipers and nuts/bolts included. All appears in good condition although obviously used somewhat. Does anybody have a link to the motor spec sheet or better yet, a manual? Would be appreciated. Thanks.
major
by major
Jun 05 2020 8:07pm
Forum: Items for Sale - Used
Topic: Deal on motors/wheels
Replies: 51
Views: 3359

Re: Deal on motors/wheels

I received a FedEx tracking number today. Says June 9th. I did send inquiry email yesterday. Fingers crossed.
major
by major
May 26 2020 3:02pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1317
Views: 118813

Re: APL's DIY axial-flux motor

Two layers of five is better than single layer of ten turns needing longer core. Proximity of turn to steel core is insignificant magnetically, according to Ampere's Law. Folks have a hard time believing that.

Regards,
major
by major
May 20 2020 4:28pm
Forum: Electric Watercraft
Topic: minkota trolling motors
Replies: 5
Views: 639

Re: minkota trolling motors

In that case it depends on what is contained in the top part. What is its function? Got a link to a web page or manual?

major
by major
May 19 2020 10:01pm
Forum: Electric Watercraft
Topic: minkota trolling motors
Replies: 5
Views: 639

Re: minkota trolling motors

steve1981 wrote:
May 19 2020 8:55pm
I recently replaced a 55lb thrust 12 volt motor with a 70 lb thrust motor 24 volt. Can I now use two batteries to run the trolling motor or not? Will the top electrical handle it?
What does this mean? "Will the top electrical handle it?" Top electrical????

major