Overvolt drillmotors

I was wondering becaus I am building a 10 bar flipper and the valve that I have works on 24V. Now my drillmotors are 14.4V. So I was wondering if you could overvolt them to 24V. I was also thinking about seting the screw on the electronise speedo down to 75% of the maximum power but I am still not shore If my motors wil burn out. Does anyone have experience with overvotling drillmotors??

Thanks

I have done many tests with drill motors (and still have around 10 lying about or burnt out :)). If you want to overvolt to 24v, try to restrict the power going into the drill motor via the speed controller if possible, but no matter what you do with current limiting etc, you must use small wheels if you are to go to 24v. Anything over 70-80mm is too much and will strian the motors too much.

I wouldnt advise running on 24v at all infact but you can do some things to reduce the chance that they will blow.
- Make sure all air vents to the motor are open and that air can travel freely around it.
- If possible find a heat-sink from RC cars/planes to fit the motors (there are some sizes that would do)
- Use the correct amount of limiting from the controller.
- Use smaller wheels, around 60-80mm should be reasonable

How much current does the valve take? As you could use a regulator to give the drill motors about 18v, which would be fine for running, and give the valve 24v (only using one 18v battery).

Cheers, Ewan
http://www.micro-maul.co.ukwww.micro-maul.co.uk

Get a 12volt coil for your valve.

Heat-sinks wont be a problem becaus I have four of them laying here. (I have 3 rc-cars)

But the reason I want to overvolt the motors instaid of geting a 12V valve is becaus you will get more power from the drive and you need bigger batterys for the same amount of Amps on 12V then on 24V. (weight)

And the screw on the speedo sets how much Volt gows to the motor om maximum rotation of the joystick.

I was also thingking about a resistor or something like that between the speedo and the motor to lower the voltage.
But I dont know mutch about resistors and stuf so maby someone can help me on this area.
Like how much Ohm the resistor should be if I want half the voltage.

I found a circuit on http://www.circuitsonline.nlwww.circuitsonline.nl that lowers the voltage from everything that has a higher voltage than 12 volt.
But that only works up to 5A and thats to less for a drill motor.

Resistors turn electrical energy into heat energy. This would be wastefull and the resistors would quickly fail. Your first idea is a winner. I was also thinking about seting the screw on the electronise speedo down to 75% of the maximum power

I like Woodys solution to your valve coil voltage problem.

another option is to have a booster to your valve and run 14.4v on your drills.

This system is used by both myself and G3 in there robots.

We have 14.4v for the whole of the robot and then on a seperate feed from the 14.4v battery we have added a 9v PP3 battery in series giving 23.4v which switches the solenoid. Not had any problems so far.

Regards
Ian

If it is possible to run off a PP3 battery for a valve, then it should be quite easy to make a regulator to feed the solenoid. All of these do reduce the chance of motors blowing, and will mean you dont habve to go to the hassle of installing cooling or heat sinks.

You may have less power, but the performance of a 14.4v drill on 14.4v isnt too bad, and should be fine for a LP flipper bot.

As Philip said, resistors are designed to turn the enerygy into heat, any resistor able to handle the current a drill motor is likely to draw would be large, and probably affixed to a heat sink, so forget that idea.

If you use 14.4v then you can use two Ni-Mh 7.2v race packs in series, which should give enough power for two drill motors and will be around half the weight of ni-cad packs.

Cheers, Ewan

Ewan I am really not understanding where you are going. A regulator reduces the voltage. That means given an imput of say 12v it would produce say 5v. I dont understand how you could regulate down the voltage from 18v to 24v?

Care to explain?
Regads
Ian

you can boost the voltage (god knows what its called, but Ill call it a regulator as it does regulate the voltage)

But the reason I want to overvolt the motors instaid of geting a 12V valve is becaus you will get more power from the drive...correct
...and you need bigger batterys for the same amount of Amps on 12V then on 24V. (weight) Nope ....Dont think so ...V/R = I... Where R is the resistance of your motor.. So your amps pull will double on 24v....So V x I = Watts... Thats approx 4 times the power.

http://ourworld.compuserve.com/homepages/Bill_Bowden/ohmslaw.htm target=_top>http://ourworld.compuserve.com/homep...en/ohmslaw.htm

as for over volting drill motors ive had my 12 volters running at 24v for over half a year. it uses 95mm wheels with hard plastic tread.

the only time ive blown up the motors is when i put tread on the wheels.... go figure.

it must be said though that the acceleration, power and speed is more than impressive at 24v :D

Weve been running two 14.4v drill motors in our 4 wheel drive for almost a year now - same motors!
Started off at 14.4v battery, but that wasnt fast enough with our 120mm Monster truck tyres, so now running at 18v Technobots Bot-Pack. Had to change the speed controllers to handle the rather large current (skid steer, 4 wheel drive, big fat grippy tyres) to a pair of George Francis H6s. Now get superb speed and control, and the battery lasts more than one fight. Only problem now is getting rid of the heat build-up inside the bot. Should be fitting some fans this weekend. :)

Woody, your right about the fact that the motors use the same amps but the valve and the 24V compressor wont. They will use less. Becaus Im not overvolting them.

And Ewan, do you have al link or somthing like that for the so called booster?

Thanks again

http://www.atv-projects.com/html/lnb_voltage_booster.htmlhttp://www.atv-projects.com/html/lnb...e_booster.html
Here is an example of a low voltage booster.

Woody, youre correct about that. If you overvolt your motors. The current will increase by the same factor as the voltage, meaning that the total power will be square of the voltage increase.

However, I think he means that everything will use a fixed amount of power. So that when lowering the voltage, you need to use more current to substain the same amount of power.

But why is 24V the goal? If you have 1Ah on 24V or 2Ah on 12V doesnt matter, its all the same amount of energy! But more importantly, the same amount of weight.

For example, imagine that your robot needs a fixed amount of energy to funtion properly during a 5 minute fight. Then it doesnt matter wether thats 24V and 2Ah (which equals 576Wh), or 12V and 4Ah (which also equals 576Wh).

So while a 12V system will use twice the amount of current, itll use half the amount of volts compared to a 24V system (which equals the same energy). So youll carry the same amount of battery anyway.

But if Ive understood correctly, youre also going to power a 24V compressor? Then youre only option will be to go for a 24V battery and lower the voltage for the drive motors. As a voltage booster cant handle the current of a compressor.

What compressor??? (I think you must have been talking elsewhere :))

Nope, he said so above:

Woody, youre right about the fact that the motors use the same amps but the valve and the 24V compressor wont. They will use less. Because Im not overvolting them.

ah, I missed that... (slaps head...) but yeah, if your using a 24v compressor then no average booster will handle the current. Would it be possible for you to get some 18v or 24v drills, that would be a simple resolution to the problem, (running on 24v).

I run 14.4v drills on 25.2v in pimp 2 with no problems, the wheels are 90mm diameter and 50mm wide and it goes like stink (unless the disc is turned on)

So you can overvolt the 14.4V drills to 24V?

14.4v motors can generally be run safely up to 18v because above that voltage you can risk burning out the motor quicker it stalled or jammed for a short while like Pimp2 found out on Sunday. :)

Ahhhh the smell or resin/lacquer burning on copper windings, nice.

Chris - http://www.featherweights.org/forum

OK, thanks!

The motor only burnt because the wheel came loose and jammed against the chassis. I am going to replace it with another identical one because I am that confident in their ability to take the load.

Can you overvolt 18V motors to 24V without burning the motors?

Read above:

http://www.fightingrobots.co.uk/discus/messages/13/2666.html#POST24358http://www.fightingrobots.co.uk/disc...html#POST24358

In general any motor that has a continuous rating can be overvolted for a short period.

But something like a car starter motor has an intermittent duty rating and heats up very quickly even under normal circumstances and is not recommended for either overvolting or continuous running at its normal voltage.

http://iis4-0.web.legend.net.uk/preview/bosch/elektromotoren/kenngroessen/betriebsarten.htmhttp://iis4-0.web.legend.net.uk/prev...roessen/betrie bsarten.htm

So in my opinion ...you can overvolt your 18v motors @ 24v.

For anyone thats interested, I got the new Maplin suplement today, and they have a special offer on 18v cordless drills. £14.99 including all the usual toot. Free delivery on orders over £30 - so thats 2x drills and something for 2 pence please!!

Also ive noticed that most Woolworths stores sell a 18v drill/driver for £12.99 which isnt bad but i havent had chance to check them out yet. As im looking for a higher volt motor to replace the 14.4v ones in Conundrum, so i dont need that extra 12v SLA battery and it can all run off of the 24v NiCads.

Chris - http://www.featherweights.org/forum

From previous expirience, the Woolworths drills are exactly the same internally as challenge, or nu-tool (the cheap) drills.

From our experiance the only problem weve had with runnign 9.6V and 12V drills at 24V with 125mm wheels was with the gearbox. Run into something too hard and snap a tooth off a nylon gear, the robot drives around a bit more then the broken tooth gets caught between gears and jams the gearbox. It only then you say bye bye to the motor.
But we had one 12V motor running at 24V with that 125mm wheels the slipped out of its mount, twisted the connection wire, which pulled it into the robot. This pulled the wheel against the chasis which jammed the motor. The motor was stalled for the rest of the fight and flatened the batteries very quickly, but didnt burn. Also our Victor 883s didnt even get warm.

Yeah i have noticed, i used to use 100mm wheels, and then i swaped to 125mm for more speed, and thats when gears started to break. Even the teeth on the metal gears started to break off. I know the Big Nipper team broke off one of the Gear Shafts inside the gear box, but hey use quite big wheels. About 150mm diamter or more is it?

Mr Stu

Stu, 6 Dia. Close enough

Great speed but without supporting the wheel shaft at both sides impacts kept bending the shaft and eventually it broke. The gearbox in blue seemed to hold up this time but it does have 5 planet gears on the last stage with the 30V drill motor (also Nutool) with 1200 rpm output speed. Pitty we couldnt get bigger wheels as this might have been able to keep up with the weaponless, err, ram bots.

well ill just throw in here that I use 4 12v drills on 24v in my feather with so far no problems at all useing 95mm wheels though it keeps the ibc warm lol

I have also used 12 volt drills at 24 volts with the infamous red wheels that r 4 dollars each and screw straight onto the drills. They work a treat but u need speed controll and a little bit of slippage if necessary which saves the gearboxs.

Not exactly over volting but does any body have any ideas on how to get the chuck off some drills.

I have removed the screw and i have tried a few methods. I have held the chuck in a vice and ran the drill. I have tried hand un screwing it. Any one else got any ideas?

Please help please
Regards
Ian

Yeah, Id like to know that too. I used the chuck of the drill to make wheel hubs. Used an angle grinder to remove most of the chuck so I was left with the small threaded part and a plate with 3 hole in it that the jaws moved though. The only problem was that after a few fights the chuck jammed onto the drill shaft and I couldnt remove the whell or gearbox from the robot. Because it was between nights of a compition we pretty much destroyed the drill gearbox to remove it from the robot, so I could get the new wheel (and new drill too by that stage) in before my next fight.

The way we do it is to take the screw out of the chuck first, an odd few need drilling out, and then put the chuck in the bench vice and rotate the handle very quickly. For a few this does not work so we short the motor wires together and try again, this works for us.

Help Please.

I have just tested my drum weapon for the first time and the drill motor im using seems to get hot quite quick.

Ive got a 9.6v old style drill motor (Where there are proper gears that slide on a bar to change the gearing). I have used the original gearing from the drill to get approx 4000rpm(if my calculation are correct). Then using round belt drive to the weapon(see profile).

I am running the robot @ 12v so would be over volting the drill motor. When testing with a 12v battery the motor gets hot reasonably quickly.

Would speed control or some other device help this? Would a different motor be better? If so which type and how much would they cost?
Note: Money is Tight :sad:

Thanks for your help
Glen

Yo,
So your turning your motor ON/OFF If this is the case, the motor is near enough at stall when its given full battery power to start the drum spinning. I would advise the use of a speed controller and start the drum up slower than giving it full voltage which will heat the motor up alot. What might be perfect for you is a 30amp Electronize Speed Controller from Technobots would sort that out. Even a 15amp might do it, but would recomend a 30amp to be safe as they can deal with drill motors at stall, not sure on the 15ampers.

Kind Regards,
Mr Stu

Yeah that was my train of thought as well Stu.
I will be getting some 30A Electronize for the drive after Crimbo anyway(providing i get enough cash for xmas) so 1 extra wont be too much difference.

Cheers