New 727 Watt 93% Efficiency Disk Motor for E-bikes

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motordude

motordude

1 mW
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It is ready for production if there is a market. Direct chain drive will power a 65 lb. ebike and a 170 lb. rider up a 6% grade hill contionusly at 17 mph with a chain ratio of 9.7 to 1 at 2860 motor rpm using 14.9 amps at 48 volts with 20 lb-in = 2.24 Nm of torque at the motor shaft with 93% efficiency. If I see a intrest of orders for 50 motors (at $150. each,Target price)
I can have them made rather quickly. As I am waiting for the 50 peice production and shipping costs to get going, you guys can discuss it to be testers or kit makers.. Your input will help everyone out. You can design a kit to mount on bikes and distribute them.

3.456" deep
6" dia.
3/4" shaft with keyway 1.575" long


View attachment 750 Watt disc motor.jpg
 

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The drawing is a bit too blurry to read. It looks like a 19mm or 3/4 inch shaft? The shell diameter isn't denoted - it looks like about 180mm? The shell depth is about 80mm. Sensorless.
What is wire #5 for? it looks like Vcc +12V - does it need a 12v supply in addition to the 48v control phases?
 
Samba said:
The drawing is a bit too blurry to read. It looks like a 19mm or 3/4 inch shaft? The shell diameter isn't denoted - it looks like about 180mm? The shell depth is about 80mm. Sensorless.
What is wire #5 for? it looks like Vcc +12V - does it need a 12v supply in addition to the 48v control phases?
Click to expand...

Three phase BLDC Neutral timing 60* hall sensor spacing 36 to 48 volts is all these were tested at so theres a lot of room for peak torque of 55 lb-in = 6.164675 Nm at 47.2 volts at 42 amps with 1987 rpm with 1280 watts out of power at the shaft. That's at the 64% efficient end. I also have a 30% longer version with a higher power limit but this will be the first one before deciding on any changes for version #2 if this one gets going.
These are vented motors and should do well at higher voltages and speeds as the wind will cool them pretty well but do not know the max wattage until the magnets roast. Quick peak power at 72 volts should be impressive! :) A $100. Kelly Controller for hall sensors should work nicely.
 
This seems interesting, especially, since you seem to provide great detail with your first post. You appear new to ES, so could you give us some idea of your experience with motor design, etc. It seems as if this motor has been tested "in theory" by the numbers you input, or is there some real-world tests that have been done with the prototype(s)?

For the price, if it stays in that range, and does what you project or have tested, then this seems like a great offering... :mrgreen:

Please keep us posted with more details, when you can. Also, when would production be completed once you finalize your design? Do you have a manufacturer lined-up? Any details you can give us about this too?

Thanks!

:)
 
Miles said:
Interesting motor.

Can you give us an example Kv; no load amps and resistance, Randy?
Click to expand...
Sorry it was 55 lb. in. of torque before it hits the max of 60 lb in of peak torque on this chart.
I will have what you need soon. The KV is a hair over 60. Perfect for a 20" wheel, a 12 tooth #219 motor sprocket and a Exrron 92 tooth and a Sram Dual Drive Hub. Have a motor that is the longer stack at 4.5 inches (motor frame minus the shaft). Theoretically, it will have a lower winding resistance and you can put more power through the motor. But that's for next round if needed. :)

The Numbers below are from a actual dyno test.
 

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deVries said:
This seems interesting, especially, since you seem to provide great detail with your first post. You appear new to ES, so could you give us some idea of your experience with motor design, etc. It seems as if this motor has been tested "in theory" by the numbers you input, or is there some real-world tests that have been done with the prototype(s)?

For the price, if it stays in that range, and does what you project or have tested, then this seems like a great offering... :mrgreen:

Please keep us posted with more details, when you can. Also, when would production be completed once you finalize your design? Do you have a manufacturer lined-up? Any details you can give us about this too?

Thanks!

:)
Click to expand...
This motor has been changed a bit for ebike use and will be produced again by the same company that made a rather large original batch a few years ago so a good price can hopefully be obtained so everyone can benefit in furthering the use of the Dual Drive hubs and a good motor that fits the bill. It will enhance ayone to make a efficient,quality ebike system at a great price :) How soon it comes to market depends on members of this forum.
 
It will be nice to see a 60kv motor capable of running single stage with good efficiency at a reasonable price.

We are all watching with interest.

Hello again Randy.........

Matt
 
Randy, if you send me one and I'll gladly make the phase measurements of resistance and inductance for you.
 
bigmoose said:
Randy, if you send me one and I'll gladly make the phase measurements of resistance and inductance for you.
Click to expand...
Thank you but I can and will do that in time. If anyone does not like the figures on the Dyno test they do not need this motor.
 
motordude said:
Nice! for a toy that has a propeller. :lol:
Click to expand...
Nice for anyone who doesn't want an orphan product, like...
OrphanMotor1.jpg
 
TylerDurden said:
motordude said:
Nice! for a toy that has a propeller. :lol:
Click to expand...
Nice for anyone who doesn't want an orphan product, like...
Click to expand...
Im Here to turn on some people to a good thing like I tried to 10 years ago. It seems that other people are enjoying the drive systems I developed and Miles has suceeded to spread the idea around since his dual drive system and his motor build I'm sure I had nothing to do with.
 
I make the Kv 65, rather than 60, based on 6.164675N-m at 42A, but still a nice figure to work with. It should be relatively easy on controllers, too, because I'm guessing that the winding inductance will be reasonably high, probably higher than for the big HXT or Colossus stators.

I've had a go at translating the data from the dyno run into a standard motor performance plot, for the benefit of those of us used to reading data in this format. I'm afraid it looks a bit scrappy as I used a demo version of Multi-Y and also because the data set doesn't include any figures for low torque. However, it should help anyone trying to get and idea of the comparative performance of this motor to any other.

View attachment Axial Flux Motor Plot.png

The figures look reasonably good to me. What would be nice to know would be some maximum ratings, such as maximum continuous current and maximum continuous rpm. I have a particular interest in seeing how fast the rotor would safely spin, as with a Kv of around 65 and a max current of maybe 50A (a guess on my part) I can think of a good use for this motor if the rotor will tolerate speeds up to around 6000 - 7000 rpm or so without flying apart.

Jeremy
 
60 KV axial flux @ 93% efficiency puts it in Lynch motor territory. The Lynch motor uses special features such as grain oriented laminations to achieve its performance. I see no special features in this motor, just the the spatial advantage that comes from the pancake/axial design. I'm skeptical and will await actual testing. I might consider it a nice option even if the efficiency numbers are lower than 93%.
 
gogo said:
60 KV axial flux @ 93% efficiency puts it in Lynch motor territory. The Lynch motor uses special features such as grain oriented laminations to achieve its performance. I see no special features in this motor, just the the spatial advantage that comes from the pancake/axial design. I'm skeptical and will await actual testing. I might consider it a nice option even if the efficiency numbers are lower than 93%.
Click to expand...

You can get high efficiency by simply under-rating the motor. Bear in mind that the Lynch design has been optimised to get the most power at high efficiency from the size of the motor. This motor is somewhat smaller than any Lynch motor, I think, but also has a much lower maximum power rating.

I'm getting very high (around 90%) efficiency from cheap model aircraft motors, by the simple expedient of rewinding them with heavy gauge wire and then running them at relatively low RPM, current and power, so the losses are dominated by friction and core losses, rather than copper loss.

I don't see why this motor shouldn't do the same. The way the efficiency drops off at relatively modest currents indicates it has a high-ish winding resistance, but then it's been designed/optimised for power levels less than 1kW when run on relatively low voltage, so this is what would be expected. It may be able to spin faster than a Lynch motor, though, which could be a big advantage in some ways. The idea of a very high rpm, fairly high voltage, but relatively low current system appeals to me.

Jeremy
 
gogo said:
60 KV axial flux @ 93% efficiency puts it in Lynch motor territory. The Lynch motor uses special features such as grain oriented laminations to achieve its performance. I see no special features in this motor, just the the spatial advantage that comes from the pancake/axial design. I'm skeptical and will await actual testing. I might consider it a nice option even if the efficiency numbers are lower than 93%.
Click to expand...
Is the Lynch brushless with more than 12 large magnets on the rotor? Do they have hall sensors for nutural timming and cost $150. including good pulgs on exit wires? These are 750 watt motors and rated that way to last for ever. If anyone wants to press the limits with them that is up to YOU.
I will do it as well and have a gas with you if you like :D
I am learning a lot every day about these motors. As I learn more I will fill you in. Talk to eacher and figure out what you can by the real information I gave you. We may have a lot to talk about soon or ???? :?: :D :lol: LOL
 
Just to fill in some numbers, Kt looks to be 0.146778 N-m/A, making Kv very slightly over 65 (not just over 60 as quoted), based on the data given above.

I've just done some quick and dirty estimates of what might happen at higher voltages and it looks like this motor would probably be able to deliver around 2.4kW at around 5000rpm and 80% efficiency on 100V. Pushing it harder, and dropping the acceptable efficiency operating point to 70%, still at 100V, gives around 2.6kW and about 4400rpm. This quick and dirty estimate assumes a linear loss change with rpm, which isn't wholly correct, so the real-world numbers would be slightly different by a few percent.

Re-wound to increase the Kv and decrease the obviously fairly high winding resistance would reap significant benefits for anyone looking for high power from a small package, always assuming that the rotor is mechanically up to it (it looks as if it may be, to me).

Jeremy
 
Jeremy Harris said:
Just to fill in some numbers, Kt looks to be 0.146778 N-m/A, making Kv very slightly over 65 (not just over 60 as quoted), based on the data given above.

I've just done some quick and dirty estimates of what might happen at higher voltages and it looks like this motor would probably be able to deliver around 2.4kW at around 5000rpm and 80% efficiency on 100V. Pushing it harder, and dropping the acceptable efficiency operating point to 70%, still at 100V, gives around 2.6kW and about 4400rpm. This quick and dirty estimate assumes a linear loss change with rpm, which isn't wholly correct, so the real-world numbers would be slightly different by a few percent.

Re-wound to increase the Kv and decrease the obviously fairly high winding resistance would reap significant benefits for anyone looking for high power from a small package, always assuming that the rotor is mechanically up to it (it looks as if it may be, to me).

Jeremy
Click to expand...
I already have larger stacks for a second run and can have any windings or magnet strengths for custom batches. Halabash Designs can aslo be implemented. But the first batch with a well used and tested motor at 750 watts all day long for years at least ebikes will have a jump on a decent motor that until now was not possible. I am sure small motorcycles could use a varient of this motor. Keep it going!
 
$150 is a justified testing price. It seems to compare closely in size and electrical specifications to the Lynch technology Perm PMS 080 4 pole-pair (8 pole?), but 93% is in between the ratings of the water cooled vs. the air cooled version. For $150 the efficiency could come in lower than 93% and I'd still consider it.

http://www.perm-motor.de/fileadmin/users_upload/pdf/PMS_Motoren-Generatoren/PM_DS_PMS_15_03-10_E.pdf

http://www.perm-motor.de/fileadmin/...0_L_Massblatt_RLS-Motor-mit_kennlinien_1_.pdf

http://www.perm-motor.de/fileadmin/...n_Englisch/PMS_080-L_TD_E_technical_specs.pdf
 
gogo said:
$150 is a justified testing price. It seems to compare closely in size and electrical specifications to the Lynch technology Perm PMS 080 4 pole-pair (8 pole?), but 93% is in between the ratings of the water cooled vs. the air cooled version. For $150 the efficiency could come in lower than 93% and I'd still consider it.

http://www.perm-motor.de/fileadmin/users_upload/pdf/PMS_Motoren-Generatoren/PM_DS_PMS_15_03-10_E.pdf

http://www.perm-motor.de/fileadmin/...0_L_Massblatt_RLS-Motor-mit_kennlinien_1_.pdf

http://www.perm-motor.de/fileadmin/...n_Englisch/PMS_080-L_TD_E_technical_specs.pdf
Click to expand...
Where would you find any disk motor at double the price or any motor of 93 % efficiency without the need of a gearbox to power a vehicle at that leval constantly ? 60 lb-in = 6.7251 Nm at only 47 volts 45.9 amps and 1287 rpm is a great start! the power and efficiency will go back up with more voltage to get out of the stall mode and make more paek torque! but for how long ? That depends on forced air at 30 mph or more! What other motor would power a bicycle with as little the amount of expensive batteries as this motor will ? This is a rare opertunity. The magnets are epoxied into bands that also hold them.
 

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gogo said:
$150 is a justified testing price. It seems to compare closely in size and electrical specifications to the Lynch technology Perm PMS 080 4 pole-pair (8 pole?), but 93% is in between the ratings of the water cooled vs. the air cooled version. For $150 the efficiency could come in lower than 93% and I'd still consider it.

http://www.perm-motor.de/fileadmin/users_upload/pdf/PMS_Motoren-Generatoren/PM_DS_PMS_15_03-10_E.pdf

http://www.perm-motor.de/fileadmin/...0_L_Massblatt_RLS-Motor-mit_kennlinien_1_.pdf

http://www.perm-motor.de/fileadmin/...n_Englisch/PMS_080-L_TD_E_technical_specs.pdf
Click to expand...

It doesn't seem that close to the Perm specs as far as I can see, when you compare price and performance. The PMS 080, 48V version seems to have a higher Kv and lower Kt, plus will probably cost a heck of a lot more. Last time I enquired about a Perm brushed motor just slightly bigger than this the price was around £800 ($1200) and I can't believe that they will be selling their brushless range much cheaper. The Perms are nice motors, but their price puts them out of reach for a lot of us tinkerers (or at least it does for this particular tinkerer.......). $150 for this motor, if the specs are OK and it's reasonably well made looks to be pretty good to me.

Jeremy
 
motordude said:
The magnets are epoxied into bands that also hold them.
Click to expand...

This looks good for fairly high rpm to me, so a version of this motor with a Kv of up around 150 might make for a really nice small motorcycle motor. I can see that rotor being able to take maybe 8000 to 1000 rpm at a guess, so with a Kv of around 130 (half the present number of turns), a 72V battery pack and an assumption that the core loss won't go through the roof with a doubling of Kt, I can see the potential to get around 7kW or more with an operating efficiency limit of around 80% (efficiency would be better than this when cruising at lower power). For a relatively small motor this looks pretty good to me.

Out of interest, what's the motor weigh? I'm guessing somewhere around 3 to 4kg?

Jeremy
 
The 3000 RPM wind of the 48V Perm works out to 62.5 KV? They have that one listed as 1KW output. It's the efficiency number I'm skeptical of and was comparing to the Perms'. After looking at the table he added, it would seem to have a somewhat peaked efficiency plot compared to the Perms.

Randy didn't have the price listed when I posted. Yes, $150 isn't in the same ballpark as the Perms. This might be a nice ebike motor.
 
gogo said:
The 3000 RPM wind of the 48V Perm works out to 62.5 KV? They have that one listed as 1KW output. It's the efficiency number I'm skeptical of and was comparing to the Perms'. After looking at the table he added, it would seem to have a somewhat peaked efficiency plot compared to the Perms.

Randy didn't have the price listed when I posted. Yes, $150 isn't in the same ballpark as the Perms. This might be a nice ebike motor.
Click to expand...

The rather peaky looking efficiency plot is what's making me think that the losses are dominated by copper loss for this motor, so it would almost certainly be better (in terms of power output at higher rpm) if wound for a higher Kv. I suspect the efficiency plot would level off a bit with lower resistance windings, as it seems to drop quite markedly as the current increases at the moment.

I suspect that the trade-off here has been to lower Kv to the point where the motor will easily work on a single stage reduction drive, and still deliver the design power of somewhat under a kW, whilst maintaining high peak efficiency. The penalty is rapidly worsening efficiency if higher power is needed, but to be fair this was probably outside the design aim. I would be very interested to see how this design would perform with a high Kv wind and a decent copper fill, as it would seem to have the potential to produce a lot of power.

BTW, I guess you missed it, but the price was quoted in the first post in this thread - it's what got me interested, cheapskate that I am :D ...........

Jeremy
 
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