Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Garabaldy on November 26, 2008, 10:33:50 am
-
Ive been trolling about on ebay looking at motors. It seems you can get nice big cheap scooter motors for less than £10!! what im wondering is do you need a scooter controller or would i be able to use my action speed controller providing the amps were within the controllers limit (which they are)
just being curious....
-
I would appreciate an Ebay number,by pm if neccessary, in order to see if they suit my need.
They are the same types of motor used in golf karts and one motor of my dad's fleet is on the bum.
Replacements cost £37.
Thanks
Sandy Calder
-
here is what i was looking at http://cgi.ebay.co.uk/Electric-24-volt-100-watt-motor-for-electric-Scooters_W0QQitemZ390006420079QQcmdZViewItemQQptZUK_Sporting_Goods_Scooters_LE?hash=item390006420079&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318
theres not much information on the listing and is there more than 2 wires coming out of the motor casing?
-
Hi Garabaldy.
It is just a brush dc motor only bigger.
I estimate on 24 volts it will stall at 16 amp.If your speed control reverses with a relay then add a 4-diode bridge to freewheel current when switches or relays open.
To see what a motor like that can do to un-protected switch contacts hook a car fan motor to a 12 volt battery and make/break the circuit with two wires.
-
sorry i have no idea what most of that meant.... :embarrassed:
-
If the speed controller reverses by means of a relay, the four diodes connected in the para "basic operation" of http://en.wikipedia.org/wiki/Diode_bridge (http://en.wikipedia.org/wiki/Diode_bridge) will stop the speed controller relay being destroyed as the motor freewheels.
The motor terminals should be connected to the ~ and the battery to + and -.
If the speed controller can handle the voltage,current and the energy stored in the motor it should be ok.
-
It looks like a larger version of the standard DC motor used in most model boats.
In that case you can use a normal 'standard' speed controller, one that can handle 20 Amps and 24 volts.
It's up to 24volts so it's best suited to a 24volt supply from your batteries.
You could try running it on 12volts (the "normal" voltage for many boats) but it may be a bit too slow as these types of motors are
usually high torque (power) but slow revving.
What type of vessel are you thinking of using it in Garabaldy?
-
something along the lines of a 2m long OSV. I havent started building yet im just planning. I may get started in a couple weeks. i would expect on an OSV that big the props would be around 100mm.
-
Without a better spec. on the motor, it's bit of a 'shot in the dark!' {:-{
-
It sounds as if you have a motor like what the tug boys use ,about 3" diameter and either grey or red with alloy end plates maybe ???.
These motors will run from 6 to 36 volts and will happily swing a 100mm prop on 12v but the rev's wont be as high as they would on a higher voltage .
Yes they will run off a standard esc but i personaly dont think the freewheel effect counts as the resistance on the prop from the water with the vessil in motion would stop a large prop almost imediatley (thats my thoughts anyway), apart from that on a full sized boat you would not normaly put the prop into reverse from full forwards throttle.
daz