DC Motor model


I’ve started an autosteer setup with an Arduino and a cytron md30c, a delphi WAS and a DC motor from an old cordless driver (hrs550sl). I have an issue with the motor, if I set low voltage (low PWM) it runs slowly and smoothly but as soon as it is under load (motor engaged to steering wheel) the motor block. So, under load the motor need a lot of voltage to be able to turn the steering wheel but then it so fast and the steering wheel is going crazy from right to left and left to right.

Is it normal for a DC motor that under load it needs more voltage to get more torque? Maybe my motor is already end of life.

I’ve seen a lot of people using the phidget 3269 which I think has a lot of torque but it’s quite expensive. So, what motor do you use?

Is someone using this motor,or similar: Bringsmart – moteur à engrenages 12 volts, haute vitesse, couple élevé réversible, 24V cc | AliExpress ? Do you think the model 140 RPM can do the job ?

The aliexpress motor is way too slow and probably doesn’t have enough power. If you want headland turns you need more speed than for just A-B guidance. Mine does 220 ish rpm with a 115mm wheel and is only just fast enough for headland turns. Mine produces about 5Nm of torque which is ample.

ok good to know, which motor do you use?

I use the 219rpm version of this with a 115mm ø 1:8 scale RC buggy wheel. It is only just fast enough for headland turns though. Andreas is testing some 500ish rpm ones, I would be interested in those.


This is my setup.

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You have to have a good motor. I originally used a drill motor from a Milwaukee drill, it worked, drew 30A on stall, made the controller get really hot, caused many electrical storms messing up usb and the arduino and was noisy! Got the phidgets motor which is around 500 to 600 rpm on 24v, used a step up from 12v to 24v to power it and made all the difference in the world. My suggestion is completely stop using the drill motor and either get the phidgets motor, or see if you can get that one from Andreas.

It will be the difference between frustration and failure, and a smooth quiet autosteer.


An interesting article on motor voltage and control. Not directly relevant but answers my questions about running my motor slightly over voltage for quicker headland turns if necessary.

…but, the motors Brian is suggesting are probably the best route.

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Dear All,

Here in France Phidgets (24 V …) or GimsonRoboics are expensive (shipping cost)
and not so easy to find.
I’ve found this motor (from china) the 12 V 585 rpm sounds OK but I don’t
know if 9 kg cm could be enough ?
For the price it could be worth trying … Any advices are wellcome …

Well, it will be noisy I would guess. ~600rpm with a 24:1 gearbox gives a motor speed of over 14K rpm!!

My Gimson motor has double the torque but I use a 115mm wheel which is quite big and it is well on top of the job. Loads of power, so your option might just work but…

I’m guessing that motor will be cheap and nasty. The problem is, you are going to put a fair bit of work into fitting it. Do you really want to risk all that time on something that might well end up either not lasting, not working at all or driving you mad because it’s noisy?

The Gimson is a tiny bit slow for headland turns at higher speeds unless you crank up the voltage a bit.

I search a new motor for a second tractor equipped with AOG. I found this motor :

Has anyone tested this motor ? It has many good specs : 7.9 kg.cm / ratio 5.2 : 1 (low resistance). However, it is too fast (1150 rpm)…

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Does anyone has an actual steering wheel ideal rpm? Around 60rpm? Or one revolution per second, or higher?

I think 60RPM is good compromise

But during my test i see an effect of orbitrol in harvester
on harvester in idle position we can see the difficulty to steer probably for lack of oil flow
on working position it is not a problem 2.5 time more flow

So the best try to rotate the steering unit to evaluate max speed can he accept

Today my electric motor has caracteristic of 1085 RPM speed 40 W
i use a gear system arount 30 mm driven pulley to 188 mm drived pulley
so i can consider theoric speed around 173 RPM

but in AOG i never set max PWM ( 150-170) so by theory 100-110RPM value for my steering wheel.

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Anyone used a motor off a kids scooter,they’ve a fair turn of speed and if they can propel a 10 year old up my yard they’ve decent torque.

60rpm is slow for decent headland turn performance. Nearer double that would be better IMHO.

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Good to all, I am new to the forum, I am from Spain and I am compiling all the material that I need to mount my gps, I found this engine in aliexpress that is supposed to be the equivalent of phidgets 60ZY105-2430, greetings.

Hi tizon1,
It looks like that motor has a RPM of 3000, it possibly wouldn’t have enough torque to turn the wheel when the PWM settings are turned down to create a slower speed. Maybe someone with more experience can clarify.

I have the reduction almost done, i designed it so with a pulley change you can change upwards or downwards the rpm, I’ll let you know soon the results

Hello, I am waiting for a response from the seller but these are the characteristics.

Hi, I tried the new motor/pulleys today, it runs at 1100rpm 12v without reduction, then a gt2 pulley behind the wheel connects to the motor with a Kevlar belt, it seems to work fine, more tests to come, the maximum rpm to the steering wheel is around 90, thanks for the advice!


Hello, I’m still investigating which is the engine that most resembles the pidghets, and this AliExpress seller sends me the one that is most similar, let’s see what you think, the image is the pidghets, thank you.

€ 57,11 | 60ZY105-2430/56JX32G 30W 24VDC 2.2A 2500R/MIN motor DC