Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
maybe you could find a proper electric scooter and just put the brushless on it. the gearing on the standard 100w scooter wheels would be perfect for that motor. maybe gary has a couple of gutted ones or maybe ebay has some would be a super easy conversion then
Fri Feb 20, 2009 4:20 pm
Rotwang Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1589
Location: Vic
$10 from the tip shop will normally get you an electric scooter with flat battery and no charger. _________________ Satisfaction is proportional to effort and results.
Fri Feb 20, 2009 8:37 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Perhaps we should have an EV scooter competition in NSW? The raw materials seem cheap enough and the scooters are practical outside a robot comp day.
Fri Feb 20, 2009 8:47 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
XD if we did that i'd so use the etek. _________________ ( •_•)
The day I stop giving 100%, is the day I stop competing
Mon Mar 02, 2009 9:11 pm
Collo
Joined: 06 Apr 2008
Posts: 130
A friend from school, my brother and I are wanting to make an approx. 2m long electric surfboard. Planning on having two S28-400 Magmotors, geared to a central shaft running into a jetski style impeller. We would run it at about 32V and have a tether to a hand held unit with a throttle for balance and speed control.
We are wanting a trigger style handle, so what should we use as a throttle? If theres anything unclear please tell me.
There are marketed petrol versions of this, but they cost a good $6500 USD.
Thanks, Chris
Fri Mar 13, 2009 11:30 am
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
i reckon you could get away with doing it cheaper using two of those gigantic outrunners on hobby city. it shouldnt take so much shock loading so the crap quality might not be such a problem
on 36-48v the power would be right up there with a magmotor maybe even better. then use 2x of the turnigy 100 amp hv controllers and a servo tester to drive it, done
the servo drivers have a potentiometer that you turn and that drives the controllers, just desolder the pot run some long leads and put it into your custom trigger handle or something like that
if your trying to run an impeller then you might well be better off with an inrunner, impellers typically want lots and lots of RPM. _________________ Mechanical engineers build weapons, civil engineers build targets
Fri Mar 13, 2009 11:38 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Sounds like a pretty expensive adventure Are you planning on using it in a creek or a dam? _________________ https://www.halfdonethings.com/
Fri Mar 13, 2009 12:13 pm
Collo
Joined: 06 Apr 2008
Posts: 130
We're hoping to get it going on the beach if possible. Then when neither of us want to paddle out when surfing, we can jump on that and catch every wave possible. Also good when there arent any waves and just cruising.
Also, saw a guy on
youtube
, who made an electric Jetski using an impeller and a Perm motor going at a stated 25mph. We were planning on gearing up the two motors a bit, maybe 1:2. Thats why we are using two motors, for some extra kick, and the ability to gear higher if we wanted more speed.
Fri Mar 13, 2009 5:54 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Just something about putting $1500 worth of expensive electronics into a box that is going in salt water that kind of puts me off it One leak, crack or shark attack and your gonna loose a lot of money.
Buy a busted jet ski and rebuilt it yourself, could be a cheap option (possibly) _________________ https://www.halfdonethings.com/
Fri Mar 13, 2009 6:17 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
if you have the actual electrical stuff in a good enough box the motors and the like should be ok with immersion
clear coat em to stop the salt from eating the AL and think about upgrading the bearings and you can probably run them up to the point of demagnetising the outer magnets ;->
IE water is ~60X better at getting rid of heat than air and the main limit to electric motor power is heat _________________ Mechanical engineers build weapons, civil engineers build targets
Fri Mar 13, 2009 7:41 pm
Collo
Joined: 06 Apr 2008
Posts: 130
The plan was to
not
get any of the elctricals wet. So lots of marine sealants, o-rings and this hydrophobic bearing greasy stuff, and a stuffing box, so that there will be water shooting out the back but not into the front. Of course, the electricals would sit in their own box and motors would be protected if any water did get into the main compartment.
And yeah, price will get a bit interesting, thats why i got my friend to help out
Fri Mar 13, 2009 8:04 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
see if you can get cable glands or plugs rated for it, cos you can get all sorts of crazy stuff happening, like water running up the insides of wires (between the conductor and the insulation) _________________ Mechanical engineers build weapons, civil engineers build targets
Fri Mar 13, 2009 8:24 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Immersing the mag motors will kill them REALLY quickly! They are not at all watertight around the bearings, brush holders or the casing - a sealed compartment is the only way to go.
You could mount them in-line with a flexible joint , which would let you house them in a metal tube. If they are in-line, you only need one gear to drive the impeller shaft.
Have you thought about your power source? Two long Mags can draw a huge amount of current. Any ideas about the ESC? The conventional choice would be a large Roboteq 2550, or you might get away with four Victor HV controllers.
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