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Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 12:00pm
by avandalen
Because the Cyclone mid-drive motor has a low efficiency, see http://endless-sphere.com/forums/viewto ... 30&t=66278, I want to use a 3205 Astro motor instead. The Astro 3205 motor has an efficiency of 90% to 95%; I have checked this with the motor parameters. The Cyclone planetary gear is good enough, it seems reliable and I can’t find another planetary gear suitable for ebikes that is not too heavy.
This is the Astro 3205 motor:
Image

I have to order this motor gearwheel for the Astro motor:
Image

I found out that the planetary gear use module 1.0 gear wheels. The pressure angle may be 20 degree, this is hard to find out.

A theeth number of 9 is rare, where can I buy this?

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 12:02pm
by spinningmagnets
Here are some pics and links that might help you find the answer

http://endless-sphere.com/forums/viewto ... 16&t=62589

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 12:14pm
by avandalen
spinningmagnets wrote:Here are some pics and links that might help you find the answer

http://endless-sphere.com/forums/viewto ... 16&t=62589
I have seen these pics but I need a much larger image, that I can use to do measurements on it.

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 2:18pm
by mwkeefer
What is the total reduction of the gearbox your intending for use with the 3205?

What is the output gear and the driven sprocket/gear on the freewheeling cranks?

My concern is cyclone motors run about 3K RPM and for the 32XX series Astro motors they need to maintain about 7500 for 90-94% efficiency

-Mike

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 6:24pm
by Gab
My concern is cyclone motors run about 3K RPM and for the 32XX series Astro motors they need to maintain about 7500 for 90-94% efficiency
The cyclone gear reduction is just enough as it is, going higher RPM is not a good idea as your cadence will be a lot higher.
Also the cyclone motor is efficient at these low rpms whilst the Astro is not. Also noise is a lot more the higher the RPM is, which would make it even louder ! what is needed is a motor that is higher efficiency and higher torque at lower RPM not higher RPM. This is a hard thing to do without making the motor big and heavy, i think the cyclone has a pretty good design and efficiency as it is.

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 08 2015 7:15pm
by mwkeefer
Gab wrote:
My concern is cyclone motors run about 3K RPM and for the 32XX series Astro motors they need to maintain about 7500 for 90-94% efficiency
The cyclone gear reduction is just enough as it is, going higher RPM is not a good idea as your cadence will be a lot higher.
Also the cyclone motor is efficient at these low rpms whilst the Astro is not. Also noise is a lot more the higher the RPM is, which would make it even louder ! what is needed is a motor that is higher efficiency and higher torque at lower RPM not higher RPM. This is a hard thing to do without making the motor big and heavy, i think the cyclone has a pretty good design and efficiency as it is.

Okay I'll spell it out.

12S @ 3205 = 7500 rpmi

Sorry between the 3205 axle and the gearbox + final drive ratio output you need an additional 70-75:1 reduction for 100 rpm cadence.

-Mike

-Mike

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 22 2015 2:32pm
by avandalen
mwkeefer wrote:What is the total reduction of the gearbox your intending for use with the 3205?

What is the output gear and the driven sprocket/gear on the freewheeling cranks?

My concern is cyclone motors run about 3K RPM and for the 32XX series Astro motors they need to maintain about 7500 for 90-94% efficiency

-Mike
>>>What is the total reduction of the gearbox your intending for use with the 3205?
I use only the Cyclone gear 1:9.33

>>>What is the output gear and the driven sprocket/gear on the freewheeling cranks
Gear ratio = 95t/12t = 7.92 (I use a spur gear instead of a chain)
Total ratio = 9.33 * 7.92 = 75.
Thus the motorspeed= 7500rpm at a cadence of 100.

>>> My concern is cyclone motors run about 3K RPM and for the 32XX series Astro motors they need to maintain about 7500 for 90-94% efficiency
Yes, the input speed for the Cyclone will be 7500rpm.
The gear runs very stiff with grease so I will use oil instead of grease.
Maybe it is good to use better bearings and better planet gears?

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 22 2015 3:06pm
by mwkeefer
Okay so to the crank (chainring) you have sufficient reduction for 12S 7500 RPM down to 75 RPM (theoretical) RPM... which wind is your 3205? What kV?

On that note, it should work well enough but... I caution you not to push too much power into the cyclone gearbox... maybe 1.5X and perhaps 2.0 but I'd test it with incremental controllers... for instance an HV110 would deliver peaks of 120A... I'm not sure the turns count but your kV must be 169 to acheive 7500 at 12S / 44.4v so presuming 44.4v and 120A surges: 5328 watts or roughly 7.1 HP and forget that torque with a 169kV the kT (torque constant) comes out as: 8.01 in oz per Amp input or 962 in oz @ shaft (5 ft lbs) input to gear box and 375 ft lbs at the cranks.

Don't even know if the cranks will support it.

I would suggest not exceeding 1500-2000w maximum or a maximum current of 33A - 45A @ 12S and even that may be pushing it a touch.

Just friendly words of caution.

One last thing, the Astro 3205 will make noise but its like a TURBO JET ENGINE spooling up and no where near the unpleasant sound of a cyclone setup but alot of that may be in the gearbox.

-Mike

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 23 2015 2:51pm
by avandalen
mwkeefer wrote:Okay so to the crank (chainring) you have sufficient reduction for 12S 7500 RPM down to 75 RPM (theoretical) RPM... which wind is your 3205? What kV?

On that note, it should work well enough but... I caution you not to push too much power into the cyclone gearbox... maybe 1.5X and perhaps 2.0 but I'd test it with incremental controllers... for instance an HV110 would deliver peaks of 120A... I'm not sure the turns count but your kV must be 169 to acheive 7500 at 12S / 44.4v so presuming 44.4v and 120A surges: 5328 watts or roughly 7.1 HP and forget that torque with a 169kV the kT (torque constant) comes out as: 8.01 in oz per Amp input or 962 in oz @ shaft (5 ft lbs) input to gear box and 375 ft lbs at the cranks.

Don't even know if the cranks will support it.

I would suggest not exceeding 1500-2000w maximum or a maximum current of 33A - 45A @ 12S and even that may be pushing it a touch.

Just friendly words of caution.

One last thing, the Astro 3205 will make noise but its like a TURBO JET ENGINE spooling up and no where near the unpleasant sound of a cyclone setup but alot of that may be in the gearbox.

-Mike
Hi Mike

>>>Okay so to the crank (chainring) you have sufficient reduction for 12S 7500 RPM down to 75 RPM (theoretical) RPM... which wind is your 3205? What kV?
The battery is 36V, the Astro 3205 should have about 12 turns instead of 8 = 226rpm/V instead of 339V/rpm.

>>> I would suggest not exceeding 1500-2000w maximum or a maximum current of 33A - 45A @ 12S and even that may be pushing it a touch.
The maximum input power that I will use is just 350W (by law :( ), which is enough for more than 25km/h without man power.

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 23 2015 9:56pm
by John in CR
mwkeefer wrote: the Astro 3205 will make noise but its like a TURBO JET ENGINE spooling up and no where near the unpleasant sound of a cyclone
That sounds quite unpleasant to me Mike, and I can only imagine how much worse the Cyclone gear reduction will make it.

Avandalen,
You're oversimplifying the efficiency gain by mentioning only the rpm. That's only applicable if you're looking at steady state cruise for long distances, and if that's the case the losses in the multiple stages of reduction are sure to more than eat up any gains. Is there a reason you're married to such high rpm, because the only valid one to me is that the rig needs to be picked up frequently or the bike goes airborne while riding. Otherwise you'll come out ahead with a larger motor turning a lower rpm with good efficiency, so you can skip the extra stages of reduction that are lossy.

If your riding is more common with plenty of stops and starts instead of long periods of steady state cruise, then a well chosen larger motor will give you better overall efficiency too, because it's run at lower stress. Less noise, less reduction losses, less heat, and the ability to better handle higher performance levels when desired are all proven with simple arithmetic that's too often ignored on the forum.

Re: Astro 3205 motor on Cyclone planetary gear

Posted: Mar 24 2015 7:02am
by avandalen
John in CR wrote:
mwkeefer wrote: the Astro 3205 will make noise but its like a TURBO JET ENGINE spooling up and no where near the unpleasant sound of a cyclone
That sounds quite unpleasant to me Mike, and I can only imagine how much worse the Cyclone gear reduction will make it.

Avandalen,
You're oversimplifying the efficiency gain by mentioning only the rpm. That's only applicable if you're looking at steady state cruise for long distances, and if that's the case the losses in the multiple stages of reduction are sure to more than eat up any gains. Is there a reason you're married to such high rpm, because the only valid one to me is that the rig needs to be picked up frequently or the bike goes airborne while riding. Otherwise you'll come out ahead with a larger motor turning a lower rpm with good efficiency, so you can skip the extra stages of reduction that are lossy.

If your riding is more common with plenty of stops and starts instead of long periods of steady state cruise, then a well chosen larger motor will give you better overall efficiency too, because it's run at lower stress. Less noise, less reduction losses, less heat, and the ability to better handle higher performance levels when desired are all proven with simple arithmetic that's too often ignored on the forum.
You're right with your arguments.

>>> Is there a reason you're married to such high rpm
All available mid-drive motors have a too low efficiency and a too high weight for me. My wish was to develop a mid-drive motor with a total weight of about 1.2 kg and an overall efficiency of > 87%. Increasing the rpm is the only way to increase the motor efficiency and it reduce the motor weight.
Here is my idea; I use just a power of 350W:
http://endless-sphere.com/forums/viewto ... 28&t=66964

It requires a planetary gearbox with an efficiency of about 95% under load, with a gear ratio of 10. But my idea may be impossible to achieve. That's why I’m looking at the Cyclone motor too, it is not as bad as I thought and maybe the motor and gearbox can be improved.