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Sources for large electric motor

M

Michael

Hi,

I'm building a model submarine it will have a displacement of around 500kg
and a length of 4m.
Having worked out a rough idea as to the size of the motor required, 3hp.
I'm now looking for suggestions. Sites like technobots don't stock ones
large enough and so I'm struggling to find an answer.
Then there is the matter of how to control the speed. Ideally I'd like
proportional control.

So, does anyone know where I can find a large enough motor, ideally with the
electronics to control it? The onboard power will be provided for by two 12V
batteries,
of which the AH is still undecided.

Thanks

Michael
 
L

Larry

So, does anyone know where I can find a large enough motor, ideally
with the electronics to control it? The onboard power will be provided
for by two 12V batteries,
of which the AH is still undecided.

http://www.jacmacscooters.com/xtr_se450.htm
(I know nothing of this dealer. Just use his website to show it.)
He has all the parts, it says, you're looking for.

The batteries are under the floorboard with the controller in front. The
batteries are also in a nylon carry case so you can easily swap battery
packs and keep riding, charging one while riding another.

My electric powerboard (skateboard) has a 450 watt, 24VDC chain-drive motor
on it. Speed is controlled by a pulse-width modulator from a jetski-like
finger throttle on the handle bars and is very smooth, limiting current
even stalled and speed to 16 mph. The brand is Blade-Z. This motor is air
cooled, but the smaller 350 watt motors are not. They simply get hot.

Power for the scooter is twin 12AH 12V AGM batteries in series. The
scooter came with gelcells, but they were really cheap and, I thought, poor
condition as they were quite discharged by the time I got them. 12AH, 24V
will power the scooter at 16 mph for 8 miles, 30 minutes, but much longer
if you reduce throttle, reducing pulse-width duty cycle. At 8 mph, it goes
nearly 20 miles on a charge. Charger is a 2.5A 24V switching power supply
that powers automatic charging electronics built into the controller board
aboard the scooter. It charges in about 3 hours because the controller
board will not permit dangerous deep cycling of the batteries. The
controller monitors battery voltage and displays on a tri-color LED green
for good, yellow for caution and red for you'd-better-get-your-ass-to-the-
charger-cause-I'm-gonna-shut-'er-down-in-2-minutes mode. At the pre-
determined cutoff point, the controller blinks the LED solid red and
refuses to power the motor.

This whole thing would be ideal for what you're looking for. The input to
the controller is a slide resistor you could easily substitute with an
analog transistor amp, or drive the slide resistor from a radio servo.

I weigh 250# and the 450W motor has no trouble powering me up the hill
behind the house, even in the "red zone". It goes just as fast near dead
as it does full charged because of the electronic controller, which only
powers the motor at full DC when climbing out at lower speeds.

Google search on BladeZ or electric scooter parts to find the
guts of it. They're all available worldwide to fix it. My motor is like
$72, about the cost of a set of AGM replacement batteries.

ON TOPIC - If your boat is a mile down the dock, these easy-to-ride, easily
controlled scooters are excellent transport from the parking lot. Remove
the seat, fold down the handle to horizontal and it locks in place to form
the carrying handle of the 50# scooter (incl batteries) for easy storage in
a car trunk or that unused quarter berth. You don't HAVE to arrive at the
remote marina stranded, you know. The flat platform for your feet is just
as long as a briefcase is wide and its width is about 3 briefcases. A
carry basket fits behind the seat but you can strap a BIG suitcase to the
seat and ride it on top of the very heavy wheel fender. I paid $299 for it
at a local sporting goods store on sale.

http://www.jacmacscooters.com/xtr_se450.htm
 
A

Awsome

Many DC permanent magnet motors are avialable in the market, biggest
advantage is controlable speed. Go in search and look for "permanent magnet
DC motor manufacturer" and you will find tons of link in there.

Horse power is variable from 0 to 20 or more, its upto you to decide what
horse power you are lookimg. With your kind of project I would think a less
then 1 horspower is enough provided you are using gear to reduce the RPM for
propeller shaft.

If you are looking some thing cheap go on ebay and type "permanent magnet DC
motor" and you can find many under $100. Remember you need dc motor driver
device to control the speed, so do some research on internet before buying
any dc motor.

Another suggestion about batteries, look for deep cycle batteries cauz it
last longer and built to stand for charge and discharge more oftenly as
compare to ordinary auto battery.
 
G

Glenn Ashmore

I doubt you will find a 12VDC motor over 1HP. www.surpluscCenter.com has
2HP 24VDC motors that draw 72 amps ad full load for $200. You might also
look at old automotive starter motors. Not sure of the HP but they are very
popular for barstool racing in the 12V classes.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com
 
A

AndreL

Find a used GE engine from a Golf cart. Some provide 11 HP at 48 volts
while the most common provide 3 HP at 36 volts. This is way enough for your
submarine because compare it to a 15 ft aluminum boat with two anglers
aboard - a troller engine can push the boat easily.

Just by curiosity is this remote controlled or wire controlled ? With a
camera or for fun ? do you have a website that shows construction ?
 
M

Michael

AndreL said:
Find a used GE engine from a Golf cart. Some provide 11 HP at 48 volts
while the most common provide 3 HP at 36 volts. This is way enough for
your submarine because compare it to a 15 ft aluminum boat with two
anglers aboard - a troller engine can push the boat easily.

Just by curiosity is this remote controlled or wire controlled ? With a
camera or for fun ? do you have a website that shows construction ?
Remote control, with a camera and for fun. No, not yet, and progress is very
slow, send me an email at SubAquaModel [email protected] (join together)
and I'll update you if you like. Planned finishing date is late 2007, so a
while yet.

Thanks for all the replies, I get back to you about what I decide
 
S

Steve Lusardi

Michael,
You should seriously consider Andre's advice. I know it isn't a 12V
solution, but it is the best one especially if you should use the complete
drive and control electronics. They are available used in junk yards at
scrap prices. Contact me off-line if you want more info.
Steve
 
M

Michael

Steve Lusardi said:
Michael,
You should seriously consider Andre's advice. I know it isn't a 12V
solution, but it is the best one especially if you should use the complete
drive and control electronics. They are available used in junk yards at
scrap prices. Contact me off-line if you want more info.
Steve

Thanks for all the comments

It's interesting: you talk to the boat people, they suggest troller motors,
talk to model engineers, they suggest 3 phase motors, talk to robotic
engineers they talk about using somekind of scooter/electric wheel chair,
talk to model submariners they suggest motors for bikes. There is no common
source shard by any of them. So I have decided why not add another
possilbility of my own?

10 1/4Hp motors, all sharing same shaft.
To control, step the voltage up/down. So have 8 6V batteries, them connect
them in such a way, so that the draw on each battery is the same. Very
cheap, and should work. And no complex controllers to interface. Only
problem is that isn't that efficient.

Michael
 
A

Awsome

Exactly..... thats what you should do. Just get any motor and get it goin

I wont be surprise if you ask any computer programmer for suggestions ...
....he would suggest ... design it on computer and done with it no need for
motor worries. :)
 
G

GregS

Thanks for all the comments

It's interesting: you talk to the boat people, they suggest troller motors,
talk to model engineers, they suggest 3 phase motors, talk to robotic
engineers they talk about using somekind of scooter/electric wheel chair,
talk to model submariners they suggest motors for bikes. There is no common
source shard by any of them. So I have decided why not add another
possilbility of my own?
Perhaps engineers don't play GOLF!

greg
 
P

Pippa Reeves

I doubt you will find a 12VDC motor over 1HP. www.surpluscCenter.com has
2HP 24VDC motors that draw 72 amps ad full load for $200. You might also
look at old automotive starter motors. Not sure of the HP but they are very
popular for barstool racing in the 12V classes.

Every car that has a starter motor in it has a 12 volt motor that has a
rating way higher than a simgle horsepower......

Most car starters pull way over 100 amps when cranking the engine....
Assuming your starter draws 100 amps at 12 volts = 1200 watts.

The last time I checked the horsepower was supposed to be something like
762 Watts....


I rest my case.


Mind you they arn't rated for long term running... tending to overheat
rather quickly!

Pip
 
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