Running 24V 150W Gold Motors on 12V

How will they perform. Im asking because i see that the 12V and 24V are the same price on technobots.

So will they work ok, what would the difference be compared to if they were 12V ones ?

The 24v version has a better bearing setup than the 12v version. At 12v the Gold should run as low as 1/4 of the power it would at 24v (half the voltage and 1/4 of the current), maybe 40w total power output, keep in mind it would aslso rev at half the speed.

The essential difference is the way the brushes are wound on the armature. Practically the 12v version at 12v would perform the same as the 24v version at 24v (exept with more current draw) were it not for the bearing set-up which consumes more power.

so really, i would be much better off just running 12V motors at 12V, Im a complete novice and i just wondered if it would be better because they would be very understressed and theres no chance of damaging/overheating them. 12V batteries are more in price range anyway.

You can look forward to lots of silly questions from me in the very near future as i try to build my first proper robot :)

Actually while im here.....

I want to build a featherweight based on two 12V 150W gold motors. Im fairly up to speed on how servos/speed controllers/H bridges etc etc work. But what i know nothing about is what is compatible with what and exactly how you connect them all together, also radio control i dont know much about.

So at the moment im thinking of a 4 wheeled robot with rear wheel drive (as i can only afford 2 motors) Would it be feasable to use tank style steering, would it still turn ok, or am i going to have to rig up the front wheels to turn.
At the moment im aiming for a robot i can just drive about, but making it so i can add weapons without much hassle in the future, and eventually 4 wheel drive.

So please help me out guys, i was looking at a 50V 20A H Bridge Speedo would that be good for me or can i get a cheaper alternative, i really need your experience here. Just to go over it again so you an be clear in what i want to build.

1.
4 wheeled robot - currently rear wheel drive but to be 4 wheel drive eventually

2.
just be able to drive about at the moment but be able to easily expand its outputs to incorparate weapons

So i need help on the best batteries to power it, what sort of steering i should use, what sort of motor speed control i should use and last but not least what remote control system to use.

I REALLY REALY APPRECIATE HELP ON THIS AS I UNDERSTAND HOW MUCH IM ASKING HERE

Ok, Ive got to start somewhere, so first Ill cover point 1. You want four wheel drive eventually, but if you put your mind to it, you can easily accomplish four wheel drive with only the two 12v Golds.

You can use gears (which are usually rated in MOD sizes) of about Mod 0.8-1 to get your initial reduction off the gold motors. You can then use timing belts and pulleys (rubbery belts with teeth on them), or chains, to link the rear wheels to the front wheels, or the other way round. A link worth bookmarking is the team hurtz drive calculator: http://www.johnhmreid.dsl.pipex.com/killerhurtz/howto/calculator.htmhttp://www.johnhmreid.dsl.pipex.com/...calculator.htm

It is worth mentioning at this point that you should use tank steering as it is the most manuverable type of drive. Also, most speed controllers designed for featherweight robots, work on the basis that the robot is tank steered with built in features such as failsafing and mixing (the process required for tank steering).

I advise you buy a Skysport 4, 40mhz RC set, complete with Rx which will cost you around 110.00. Once youve brought it, you should find it quite easy to plug into any speed controllers you may buy, and youll have two channels free for when you want to add weapons.

For batteries Id advise you just get some cheap 12v SLA (sealed lead acid batteries) of around 4-7Ah, and then you just need to get a cheap 4Ah or so SLA battery charger.

We run the 24v GOld Motors in Kitty at 14.4v. Kitty is quite nippy, and as its running a 24v motor at 14.4v, the current pulled is next to nothing. We havent blown any 20amp fuses yet. Means batteries last longer, etc, less power speedos needed, and also not as much gearing needed! saves alot of time, hassel, weight and effort, also as its been said, the 24v motors are better built - well the wrong bearing face is.

A 12v gold running at 12v, that will pull a bit of current. I think TKM2 (MIni M2) used 12v motors at 14.4v - and was pulling tons of current and all sorts, needed lots of gearing to gear it down and all sorts, and changed motors right away due to them pulling too much current. We had the same problem with kitty when we got the 12v motors, and quickly switched to 24v ones.
Kitty was the first robot to use the gold motors, and the longest running gold motor running robot. LOL!

So might be an idea to get the 24v version as you can use it at a lower voltage with less gearing and battery power- and can later upgrade grade your batteries/gearing to 24v or whatever to get more speed/power.

Mr Stu

If youre wanting 4 wheels, but only driving 2 of them, just drive the opposite corners rather than the 2 back wheels....... will make for a robot that behaves like a 4WD one, and youll find it runs far better !

Welcome to the forum BTW !

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

well i will definately be getting 12V batteries as they are in my price range, i havnt seen any 14.4 ones. So i dont think the 24V motors will be good for me.

The motors i am looking at are at http://www.technobots.co.uk/en-gb/dept_201.htmlhttp://www.technobots.co.uk/en-gb/dept_201.html are the specs for the 24V version the same for the 12V then ?

I cant work out what kind of speed controller i need. if i am correct in thinking the elctronize range can only handle one motor per controller then is an H bridge going to be a cheaper solution as they handle 2 motors. Looking again on technobots i am unsure which one i would need http://www.technobots.co.uk/en-gb/dept_518.htmlhttp://www.technobots.co.uk/en-gb/dept_518.html I think i could use the first one if i get a heatsink for it, but i am not sure. I dont know what current my motors will run at or what actually controls the current for that matter ?

Also how many batteries would i need ? Coz i see they are listed as producing a certain current for 5 minutes. So i need my current question answer to work this out.

those controllers should be fine with a heatsink. You would need 2 of the electronize, but they do have failsafes were as the H Bridge ones dont (that an extra £20 at least). But i would probably go for the H-Bridge.

SLA batteries are mainly only available in 12v, to get 24v you wire 2 in series, when stu said 14.4v this is achieved by using Nicad or NiMh batteries (better but more expensive). Your battery size will depend on gearing ect, but i would suggest for a pusher then one 12v 4Ah SLA battery is probably enough.

Golds are great little motors, ive used them for years in Alpha and have served me well, but make sure you get your gearing right, ive seen alot of robots with golds that have never seemed to get all of the power out of them, and considering they weigh 800g its alot of weight, to only be using a small amount of their potential.

So where would i find a suitable heatsink and how would i go about attatching it. Is it set up so i can easily screw one into place ?

What would you suggest as a gear ratio to get all the power out of them ?

Also, so what happens if i got two batteries and wired them up in parallel, they would just last longer right ?

actually after playing with that calculator link u sent me Ewan :) how does 7 to 1 sound ? That gives me 10.8mph and 13kgp, 123N, 28lbs of tractive force with 125mm wheels.

Those are solid rubber wheels, good ?

Ah and ive just realised the current the motor draws is due to how hard it is working right ? So what is the maximum the motor will draw, can i limit it to something sensible or what ?