Hacker questions

[cy]

i have a couriosity about these and other brushless motors... especially after tehy have set some awsome speeds down... first and biggest, what type of rpm's do thse motors produce with say 24-32 cells?

second how tourqy are they?

beyond special esc's do they require any other special equipment

ok i think thats about it for now.. i'm sure i'll have more questions soon

 

[Climate Boatworks]

Brushless motors are not really limited in RPM. The limits are how many amps you can bush through the speed control and how many turns the motor has. More turns = more torque, less turns = higher RPM.

Most motors have bearings that are rated up to 60000 RPM.

RPM will depend a mostly on the type of boat you put the motor in, and what type of prop and drive system you use.

Sub surface drive will be lower RPM than surface running systems.

There is nothing special to a brushless motor. you do not even need to oil the bearings as they are sealed.

Keep everything clean and dry and it will give you years of flawless performance.

Peter R.

www.climatemodels.com

(The fastest, The best, THE END!)

 

[Andrewg]

And the torque is enormous - produced mostly at 0 rpm - right where its needed

And the power bands extend over at least 30% of the motors rpms - so take a 30000 rpm motor its has a 10,000 rpm wide power band.

 

[RBidwell]

Andrew how can you have torque at 0 rpm. An example of the rpm's of brushless motors, in the 122 mph pass Joreg's motor was turning over 48,000 rpm.

 

[CySlyde]

wow.. thats cool... so how much voltage can these motors really handle?

thanx for all your help so far

 

[RBidwell]

The voltage is determined by the size of the motor and the number of winds similar to brushed motors. The controllers seem to be the sticking point with a 170 amp model the biggest available right now. Patrick Mcdonald was pulling 90 amps on 4 cells in his 51 mph record on a brushed motor.

 

[Andrewg]

Ray

the max torque and current are at 0 rpm - its called stall torque and rpm - altho the motor is not turning it is actually drawing the maximum current and applying maximum torque at stall

Cy

Brushless motor voltages in RC are limited to 32-36 cells by the availablility of controlelrs and and a class limits of peak RC organisations

The voltage affects rpm - and electrical properties of the windings and motor size willa ffect the rpm/v. The itnernal reisstance and mass and diameter will affect how many amps you can put thru it

About 20 gms of motor per cell and rpm/v of 1000-5300 rpm/v as you go from 32 to 6 cells in a rigger

Picking from well known brands you should have the right resistance etc to let you go fast

Mega and Hacker motors have been tetsed at up to 110,000 rpm for 10 second periods

 

[CySlyde]

110k dang.. i'm not really thinking of one till proly a year from now... kinda just really interested since i've been reading about all the records they have been setting...

on another note would it be counter productive to run two brushless motors and two props?

 

[Andrewg]

Cy

probably counter productive certainly expensive - u need two controllers and two motors

the fastest boats are all single motors - electric motors get more efficienct as size increases (unlike IC motors) so one is better if you can do it

lots of people run tins on gear boxes to a single out drive

or twins to counter rotating props

no other twin setup is easier than electric.