Thinking about motors

nasukaren's picture

This is where I'm going to write down some of my motor considerations.

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1. HXT 80-100-B 130Kv Brushless Outrunner (eq: 70-55) and its big brother, the 180kv model

These DC brushless motors look absolutely fantastic:
http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=5139
http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=5142

The price is fantastic ($150) and the power can't be beat. And the size is just right as well. The only problem is finding a speed controller that can handle their 100+ amps and is equally reasonably priced. I don't want to spend $400+ for an Alltrax AXE....

Hmm... looks like I can use a model R/C controller with a servo tester as an alternative.

The only other problem is the RPM.... 130 rpm / v = 130 rpm * 24 v = 3000 rpm...... ?

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before comments

Comments

chas_stevenson's picture

3120 rpm

Grandpa Chas S.

Jeffkay's picture

The problem with the ESC controller for a plane is that it cannot slowly start the motor. It will come on fast and jerk your ride. Also, the motor you are looking at is meant to be cooled by the "fan" of the propeller. Unless you can cool this it will not live long. Also, the bearings will probably not live long as the RC plane, being a "hobby" device, is not meant to run long. The 8000-10000rpm is very hard on bearings and they probably won't last in an EV/bike. The Alltrax AXE will not run a motor like that. If you must use these motors, try the Kelly controller for brushless motors. It may solve the start-up problems but you will still have the other issues. If you are doing something heavier than a bike like a scooter, then maybe you should look at the Etek brushless. It is robust and not too expensive.
Jeff K.

andys's picture

This fellow put together exactly what you want to do with that exact motor, but the effort and skill required to make it work are off the charts. he documents everything you need to do to run that motor on an e-bike here. I think after you read this, you will realize it isn't a practical option.

http://www.wisil.recumbents.com/wisil/shumaker/default.htm

nasukaren's picture

Jeff -

My bike is a moped which has the pedals to kickstart the motor and a centrifugal clutch which I've retained. So I just have to push off with the pedals and hit the throttle to get going. :-) The centrifugal clutch also means I can't stall the motor, which is important.

I've the motor on order and am looking for a good controller for it. Or maybe just a cheap controller since they seem to go up in flames pretty quickly. :-)

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

andys's picture

The people who have already tried this have said that RC motor will not work with a standard EV style brushless controller. that motor does not have hall sensors in it. Read the article in the link above, as it spells out what you need to do to make that motor run and how to control it.

Jeffkay's picture

Karen, Like the E-cumbent mentioned earlier, a slip clutch or real clutch and gearing the RPM's would work. You still have the longevity issues, heat issues and the fact that given the small shaft and all, there are no off-the-shelf parts to easily do what you want. There is an Etek brushless and controller on e-bay currently for $500 that would be perfect and 36v setup. That would let you keep the ICE because you would have less batts to hang on the moped. Another idea if you keep the ice is to start with the ice and kick in the RC motor controller at speed and kill the ice. This would be like a hybrid. Since you have a centrifigal clutch I doubt you could roll-start the ice again tho...

Jeff K.

nasukaren's picture

Jeff -

Thanks for your comments. Well, the motor arrived and I'm waiting for the controller and the throttle (servo tester).

Mounting the motor should be simple as the motor mount provided will fit well into my current system. The shaft is 12mm which also works for me as my current v-belt pulleys are 1/2" bore which is 12.5mm, so I just need to shim it just a tad.

I'm worried about longevity and heat. I'm running it at half-voltage (24 volts and not 48 volts) and a lower amperage (50 amps vs. 100 amps) which should help keep it cooler. I also plan on mounting a truncated propeller blade on the other spindle which I'm not using, to direct some airflow over the motor.

It's the experimenting that's the fun bit. As long as no one gets their eyes poked out!

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

jdh2550_1's picture

It's the experimenting that's the fun bit

Ain't that the truth!

I also plan on mounting a truncated propeller blade on the other spindle which I'm not using, to direct some airflow over the motor. ... As long as no one gets their eyes poked out!

How about if they get their legs shaved by the prop? Or maybe that's a feature you could market? ;-)

I'm just joking of course - if you use a prop you'll have a shroud. Another alternative for air flow could be a short section of "dryer vent hose" to route the airflow from the front of the bike over the motor. It could also be made to look like a ram-air system for your moped...

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

nasukaren's picture

I've been seriously thinking about the ram jet idea! It'd be nice to get some *clean* cool air over the motor. Maybe some ducted fan assistance would work too!

This is turning into the Rube Goldberg mo-ped!

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

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