Speed controller current

[gizz]

Hi.

Im curious how much current a speed controller for a heavyweight should be able to give continiously when running with
Wheelchair motors, Bosch 750's and the mag/ampflow motors, roughly?
I'm a bit confused since there are so many different controllers on robotmarketplace with roughly the same price.
Should i use something with handles a range of 60 amps continiously or higher / lower?

I know gearing and wheelsize / numbers of wheel driving etc counts in but a rough estimate.

[typhoon_driver]

Re: Speed controller current

how long is a piece of string?

In all seriousness, you need to have some restrictions on your system before you can work out rough current draw values, even things as simple as whether you are going to run the motor at it's rated voltage, or go higher or lower vastly affects the numbers.

I believe there is a calculator kicking around on the net somewhere that allows you to play about with the values but I can't for the life of me remember where. I'm sure someone else will be able to post a link.

[gizz]

Re: Speed controller current

Yeah ofc there are tons of things which affect the deal but it would be interesting to see what motors
and controllers you heavyweight drivers use on your robots and if u run at the correct voltage or higher.
It could at least narrow it down a bit for me.

[woody]

Re: Speed controller current

http://architeuthis-dux.org/torquecalc.asp

[gizz]

Re: Speed controller current

That was very handy woody, thanks.
Tried a bosch 750gpa with an 8 inch wheel with an 8:1 reduction. It says 49,7 amps to spin a wheel and 99.3amps peak.
So a speed controller for 60A continous with a peak capacity with say 120 would be almnost perfect then?
I suppose the amps to keep the wheel spinning once started will lower but just to be sure.

Couldn't really find motors in the list named wheelchair ones, does anyone know roughly what currents they draw?

[widow_twanky]

Re: Speed controller current

That was very handy woody, thanks.
Tried a bosch 750gpa with an 8 inch wheel with an 8:1 reduction. It says 49,7 amps to spin a wheel and 99.3amps peak.
So a speed controller for 60A continous with a peak capacity with say 120 would be almnost perfect then?
I suppose the amps to keep the wheel spinning once started will lower but just to be sure.

Couldn't really find motors in the list named wheelchair ones, does anyone know roughly what currents they draw?

Theory's always fantastic. I found the NCC70's (70A) would blow reasonably regularly on a bosch 750 at 36V. For Bosch's I'd go for either a roboteq which has a 120A continuous current

Andy

[woody]

Re: Speed controller current

That was very handy woody, thanks.
Tried a bosch 750gpa with an 8 inch wheel with an 8:1 reduction. It says 49,7 amps to spin a wheel and 99.3amps peak.
So a speed controller for 60A continous with a peak capacity with say 120 would be almnost perfect then?
I suppose the amps to keep the wheel spinning once started will lower but just to be sure.

Couldn't really find motors in the list named wheelchair ones, does anyone know roughly what currents they draw?

Ummmm...you sure?

Did you alter ALL the parameters correctly ... e.g. weight 220lbs

I get the following for 2 motors ( one per side ) , 100kg's @ 24v

Torque (per motor) to spin wheels 792 oz-in
Amps (per motor) to spin wheels 91.034 Amps
Theoretical Top Speed 11.923 MPH @ 24v & 17.885 MPH @ 36v
Total Peak Amps 182.06 Amps
Amp Hours Required - 3 Min 6.3724 AH
Amp Hours Required - 5 Min 10.620 AH

You might be able to relate the NPC range to a wheelchair motor/gearbox combo

http://www.npcrobotics.com/products/vie ... 0&mode=gfx