Solar Freaks

For those of you that have used both motors, which do u think is the better of the two.

now my team owns no less than 14 motors, mostly maxon, but in recent years we have obtained some from faulhaber. i would firstly like to say that faulhaber makes good motors, however, maxon are far better. when the fauls are geared right and properly fitted - ie the sleve isnt halfway up the shaft - they are fast, but the maxons will never fail no matter what you do, and they can be made to go just as fast if they are set right. plus they dont fall to pieces.MAXON!!!!

Both motors have their benefits. In the next few days, ill explain these in detail, with reference to motor data sheets and terminology. Ill give you guys a detailed explanation of all the data sheet terms, and what u need to look for in a motor.

Here are the datasheets for the current most successful motors from both faulhaber and maxon.
The maxon 4.5volt 10watt with extremely low terminal resistance produces heaps of starting power when used with a maximiser.



This is the now most commonly used faulhaber.



I think if geared properly the maxon would be a winner.

Also the maxon motor weighs nearly 60grams more, so for really light cars, the benefits could be offset by extra weight.

OK we know the mini-motor 2232 is the new good motor that everyone uses, but i just noticed that it doesn't even have ball bearings in it . Why doesn't it come with ball bearings? and how much difference will we notice if we had ball bearings installed?

Data sheet states that ball bearing are optional. If you want ball bearing on the motor itll pobly cost more because its an option and you have to get it specially ordered.

under heavy loads ball bearings have less friction compared to bushes but im not sure by how much.

Pulled apart a maxon.. here are the pictures.
Biuld Quality seems better than faulhaber.

Ian Gardner from Victoria has just finished testing of the Maxon RE25 118740, and he just confirmed it is currently the best available motor for solar car. Current estimates are a 0.5 - 1.5 second decrease in lap times. The motor provides up to 80% more torque per RPM compared to the faulhaber 2232. Although it weighs 75grams more, he stated the benefits easily compensate for the extra weight and more.

The official results will be released in his latest car design hints due in the next few weeks.

I'm looking for help with solar boats. My school competed in melbourne and had the fastest primary boats in full sun, but we dropped off in low light. What's the answer?

maybe you need a higher torque motor for lower light conditions?
What motor did you use, and what was the voltage of you panel?

primary boats are limited to motors worth less than $20. ours were hobby motors from scorpio. our panels were new, also from scorpio. voltage varies slightly but up to 6v

In low light conditions, you may need to connect your panels in parallel to get the extra current required by your motor.
In low light conditions solar panels put out bugger all current.

A solution I saw for this was a switch that allowed you to switch your panels between series and parallel. Something like in the image below.

Hey unussapiens, great diagram.

Cheers.

Hello solinvicta,

Because you are running without electronics, you will need to match your load (motor) to your solar panel to make use of all its power. To receive this maximum power for different light levels you will need to change your boat configuration.

In the case of a model solar boat this is most commonly done by changing your propeller and/or, as Tony and unussapiens have mentioned, rearranging your panel wiring configuration. Less common options may be to change motors or gears (if you aren't running a direct drive system).

If you are using the standard Scorpio boat panels then the panels can be set up to be easily switched between series and parallel configurations using a double pole double throw (DPDT) switch as in unussapien's diagram (a DPDT centre off switch can be used so that a separate on/off switch isn't needed).
At 6V it sounds like you have your panel wiring in series and so making the parallel setup available to you should already go along way to improving your performance at low light levels. A propeller change will probably also be necessary to get the maximum out of the panel. As Tony has mentioned, changing to another motor in very low sunlights could also improve performance.
The easiest way to determine your best setup for a particular light level is to just do some testing with your boat if you can.

If you haven't already had a look, the Tasmanian website (http://www.tassolarchallenge.org) has a help file titled "Model Solar Boat Help" written by Ian Gardner on the CHALLENGE HELP page. This is a very useful file and I recommend that you have a bit of a read.

miseli

Hi guys,
bit new to this stuff so sorry if i ask some silly questions!
Does anyone know if it is ok to run a faulhaber 2232 motor in reverse polarity?
Thanks in advance!
Craig

Yes it is ok.
Some motors have timing advance, and could run faster in one direction as opposed to the other, but on the 2232 it doesn't make a difference.

great, i remember the old r/c racing car days and running up to 20 something degrees advance.. Thanks for that!

Hi everyone,

A couple of weeks before school ended last year I dropped past New Town HS to grab a few things that they had borrowed from me for the solar challenge. While there I ended up helping the students sort out some of their gear and we uncovered a bunch of old 2232 Faulhaber motors which had been hiding in various places. Eleven 2232’s to be exact!


Problem was that all of these motors were damaged in some way due to having been mistreated by students in previous years. This rendered them all but useless for the model solar car challenge in their current state. Remembering that each 2232 costs around $150, this amounts to a ridiculous sum of money simply going to waste.

Anyhow, the motors seen above were affected in either one of two ways with the first of these being in the form of a ripped out or broken off motor terminal. The second has to do with an increase in axial motor shaft play and this can lead to motor brush damage as well as affect gearing alignment.

Here, a closer look at one of the 2232's from above reveals that one of its terminals have been ripped out. This means that one of the terminals to which the motor leads are normally soldered to has been accidentally torn from the motor. This then leaves nothing or very little for new wiring to be attached to and therefore no electrical contact for a current to run through the motor.

Here, one of the 2232's from the set above can be seen to have had its shaft loosened due to the movement of the brass sleeve which would otherwise be holding it in place. This occurs when too much axial load has been applied to a motor shaft causing the brass sleeve to slide out along it. If this movement becomes too great (ie more than say 1-2mm in contrast to the 0.2mm of a brand new 2232 as stated in its datasheet) and the shaft too loose, the precious metal brushes inside the motor can become damaged due to incorrect alignment with the commutator.

Anyways, not liking the idea of knowing that all these expensive motors were just lying around going to waste, I offered to take them home with me in the hope that some could be rescued.

Given that I have heard several stories of similar things happening at other schools I thought that it might be good idea to discuss a few measures that teams/schools may like to take in order to minimise the risk of experiencing what has been outlined above.

1) In order to reduce the risk of ripping or breaking off motor terminals I would suggest taping or cable tying the motor leads to the motor in a manner similar to that which is portrayed in the pics below:



As can be seen, either of the above methods will work and both ought to minimise the chances of any stress being placed on the motor terminals if done properly. Many model solar car and boat teams adopt one of these two approaches.

2) To prevent the brass sleeve from sliding along the motor shaft, keep axial loads to a minimum. This should be pretty straight forward if using pinion gears that are fixed to the motor shaft using a grub screw.
A little more care needs to however be taken if using press fit gears. This is because a load will need to be applied to the shaft in order to push the gear onto it.
Most Maxons that are used for the solar challenge with sleeve bearings have a maximum static axial load rating of around 50-80 Newtons (ie approx. 5-8kg) and the Faulhaber 2232 20 Newtons (ie approx. 2kg).
Press fit gears usually require more than the 20N of force to slide onto the 2232 motor shaft and so this means that teams using this form of gearing will need to be cautious.
I personally used press fit gears in the years while I was competing and never had any problems even though some of the axial forces applied to the motor shaft would have exceeded the 20N.
I would however advise that press fit gears be added and removed as infrequently as possible. This means that if you want to change gear ratio then change the spur gear on the wheel and not the pinion gear on the motor. The only time you should really need to remove a press fit pinion gear is if it becomes damaged and needs replacing.

In the event that the brass sleeve does move and shaft play does become too great, you will need to slide it back to where it belongs. This can be done by clamping the end of the motor shaft in a vice and then levering the sleeve back towards the front motor face and into the intended position with a set of pliers or a screwdriver. When doing this make sure you have pulled the shaft out so it sits in the correct position. This will ensure that you know how far to slide the sleeve and also means the motor brushes are aligned with the commutator. When levering the sleeve back into place, do this little by little as you don’t want to go too far and then leave no shaft play at all.

Finally, but still on the topic of motors, I’d just like to say that I believe that TonyB will be looking to order in Faulhaber 2232's directly from Germany later this year and then sell them on to schools for around $70-$75 at SolarMPPT.com. That's less than half the price of what places like Scorpio, Erntec, Camartech, etc have been selling them for of late.

Marc