quote:Originally posted by miles&Jules:
A lower wattage winch motor would mean faster rpm right?
Not really, it's dependent on how they are wound. A 100 watt scooter motor only does 2500rpm, but a 100 watt drill motor does 18000rpm, this is because the drill motor has less turns of wire, but uses thicker wires which uses more amps. _________________ https://www.halfdonethings.com/
Wed Dec 19, 2012 11:09 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
oh ok...i'm getting my amps and watts mixed up. Wanda's 700ma winch motors would run slower than Rage quit's 300ma winches ,on the same voltage? _________________ Miles Blow - Julie Pitts
www.mulesfilm.com.au www.wombokforest.com.au
Hmmm not quite. The speed of the motor doesn't matter if they are 300W or 700W. This is due to other factors. The kV on the motors is an indication of how fast they will spin. Regardless of size.
However if you stalled both the motors the 700w one would have 2.5ish times the current going through it. Than the 300 which would generate 2.5 times more torque.
Watts is the correct term, RageQuit uses 300 watt winch motors, Wanda uses 750 watt. Wattage doesn't have any relevance to RPM of a motor (AFAIK). _________________ https://www.halfdonethings.com/
Wed Dec 19, 2012 1:14 pm
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
So the speed increase between the 12v100watt scooter and the 24v100watt scooter running on 6cell was because i was over volting the 12v...nothing to do with the wattage?
quote:Originally posted by miles&Jules:
So the speed increase between the 12v100watt scooter and the 24v100watt scooter running on 6cell was because i was over volting the 12v...nothing to do with the wattage?
The 12V 100W scooter motor and the 24V 100W scooter motor both do 3600RPM at their respective voltages. However, the amperage draw between them is the main difference. The 24V motor running @ 100W is only 4.1**** amps, the 12V motor running @ 100W is 8.2**** amps.
When you double the voltage of a motor, you also double the amperage, this effectively 4X's the wattage. 12V @ 8.2Amps = 100 watts, however when over volted to 24V, this is now 24V @ 16.4Amps = 400 watts!
**** - These amps values are in a 100% efficient world, in the real world they would be higher values due to lower efficiency.
quote:Originally posted by miles&Jules:
So what would stress the new double tz85 more a 1400watt or a 300watt winch?
The 1400 watt winch will. 1400 watts / 12V = 116.6Amps.
While the 750 watt winch is, 750 watts / 12V = 62.5Amps. _________________ https://www.halfdonethings.com/
Wed Dec 19, 2012 2:43 pm
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
The limiting factor for output power for an electric motor is heat.
Generally a larger (physically) motor will be able to dissipate more heat than a smaller one. Larger motors also use larger wires so less resistance = less heat generated in the first place.
Within the motor, the number of turns sets the RPM per volt. More turns means lower RPM but more torque and vice versa.
In short, you can trade anything for anything volts and amps and RPM wise. But no matter what you do the motor will only ever be able to put out the same amount of power in the same physical package.
Robots we can cheat because we only run for 3 minutes, electric motors are rated at their continuous 24/7 rating. So we can get things nice and toasty, then stop. _________________ Mechanical engineers build weapons, civil engineers build targets
Thu Dec 20, 2012 9:57 am
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