100watt scooter motors only do ~2500RPM on 24v. So if you gear it 2:1 you only have 1250RPM, which isn't much for a vert spinner
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So you reckon Reboots drum isn’t spinning quickly enough.

And yes to those that didn’t know Reboot is using a 100w scooter for its weapon.

IIRC, Reboot runs on 30v... which is ~3100rpm and from what I can recall of inside of Reboot, it's about a 1.5:1 ratio, so ~2000rpm at the drum, which is much better KE wise then ~1200rpm

Using a standard sized drum of 4" diameter, 0.2" wall thickness and 8" wide, @ 1200rpm you get 91.4joules, but if you run it @ 2000rpm, you'll get 253.8 joules... or a 277% increase in kinetic energy....

800rpm difference is a lot in KE..
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You make a point with Reboots voltage [24 cells] but as Ali didn’t specify voltage, [that was Tim] and it is customary to over volt motors in combat bots and he was asking who had experience with 100 watt scooters as weapon motors I thought Reboot was a relevant example.

My motive for questioning your original statement

“100watt scooter motors only do ~2500RPM on 24v. So if you gear it 2:1 you only have 1250RPM, which isn't much for a vert spinner “

Was to try and draw you out as far as your somewhat dogmatic interpretation of the motors specifications.

The 2500rpm at 6 A at 24 volt rating is I suspect accurate enough.

The point I wont to make is that the free rev speed is 3670 at 24volts. Reboots drum is on ball bearings and I suspect the aerodynamic drag is fairly low with his normal drum.

If you wont to dazzle me with your mathematical skill you will need to factor in a few more variables as I suspect the speed is higher than your estimate.

Reboot is in bits at the moment so I cant put the taco on to check but I will do rev and current checks before Robowars now Ali has got me thinking.

Reboots drum is closer to 7” wide 4.45” diameter 0.15” thick and weighs 2.45Kg
The friction drive wheel is 4” diameter.

The maths speil was just purely to show the relation of RPM to a KE weapon. Using Reboot as a higher then spec design to a standard setup at nominal voltage and ratios as explained by Ali. It was not a "dogmatic interpretation" of the motors specifications.

quote:

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The point I wont to make is that the free rev speed is 3670 at 24volts

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I deliberately used an SLA for the no load test, the voltage with the motor at the 3670 RPM was 24.8 volts so your 28 volt is way off.

The scooter runs off 4 Ah SLA’s in its designed application so that is what I tested it with.

I had a 100watt scooter motor running 18v geared up 2-1 spinning a 4.75 kg drum and it had enoughf torque to spin it up rather quick.

Id say if you run 24v gear it up 2-1 so thats like 4600rpm abouts on a 2kg disc i dont see why it wouldent work i had less voltage and more weight then that and it spun up fine and did some damage.
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Tim Team Reaper.

Just tested Reboots actual weapon motor 3970 RPM no load at 24.3 volts so this is a run in motor that has been in 30 fights and done lots of demos and the odd rumble.
So despite Aaron’s assertion

Quote”100watt scooter motors only do ~2500RPM on 24v. So if you gear it 2:1 you only have 1250RPM, which isn't much for a vert spinner ”

I feel that the 100-watt scooters can make an effective weapon motor.
They can take a lot of voltage if your drive motors can too and they are so low current it makes sense to use one pack for drive and weapon.

Ratio is a compromise between spin up time, max revs and current draw as well as physical constraints with your choice of drive arrangement.
I prefer some built in slip or friction drive.

Even though its not a spinning weapon just adding some info on the 100 watters being used on Pod.

The ratio of the drive is 2.7:1 with a drive diameter of just under 3 inchs.
The robot weighs just under 20 kilos and indoors on a flat floor like the arena it drives and turns without slowing down at about 14.4 volts, sometimes at 12 volts dending on the battery, so at 14,4 volts that would make it a 30 watt motor driving a 20 kilo tracked robot.


Only at slow speeds does the motor warm up and only when the batteries are starting to fade voltage that they get hot.

They seem to want to last.
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What do you guys think about a 1:1 ratio on the motor to the disc . I forgot to explain earlier that i am planning to run the motor at 24v and not over or undervolting it.
Just noticed on ebay they have some 120W scooter motors for the same price as the 100w , would these give any improvement in performance ?
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All the motor dose it get the disc up to speed really the more powerfull the faster it will de so.

The damage comes from the weight and speed of the disc.
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Tim Team Reaper.

In case anyone is wondering why the Valiant fan motor is better of with a 2 to 1 ratio and the scooter can run 1 to 1 the fan runs right out to 9000 rpm at 12.0 volts. 15670rpm at 23.5 volts on the one I just checked.

Like Tim said it’s a KE weapon and like Aaron proved the more speed the more potential energy.
[It gets to a point where that can work against you but that is another subject].
A 120 watt scooter is just wound with a few less turns, on a given voltage it will draw more current and get the disc up to speed a little bit quicker and turn it slightly faster.
Upping the voltage does the same thing.

Why is everyone putting so much trust in the chinese spec sheets. I have gone over the spec sheets for the 300W scooter motor and found that they don't show all the information for the motor. Just from extending their graphs out you can see that a 300W motor can actually put out 550W when under a decent load (like when powering an axe or starting up a spinner). The max amps is also a lot higher. Looking at the specs of the 100W motor it looks like it could almost reach 200W under the same loads. So since I don't really trust the power and max amps listed in the specs its pretty easy not to trust some of the other information they list, such as unloaded rpm.

I guess spec sheets should be taken with a pinch of salt.... or in this case, a table spoon
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For a while now have been using Jaycar motors and the only data on their power in their manual says 53 watts, but they only refer to power with maximium efficiency in mind.

Sometimes considered changing motors because it only says 53 pissy watts but the motors seem powerful enough.

Might be the same for the scooters, the are meant to be efficient so maybe its a figure for efficiency under load.
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