Sorting out drill motors

[RogueTwoRobots]

Sorting out drill motors

If theyre 9.6V at 14.4V then it should be going pretty damn quickly (on 75mm wheels yeah?) as thats the setup Im running too at the moment. Check all the points that James said, but particularly with the wiring of the batteries/motors. Im using four 7.2V packs in mine, wired in parallel to boost the Ah then wired in series to get the 14.4V - first time I connected it up though it was reeeeeaaally slow, was majorly disappointed. Was the next morning before I realised I they were only getting 7.2V and that I had duffed the connections

[jamesb]

Sorting out drill motors

its actually the motors being in parallel im refering to Jamie, not the batts.

If you are running 4 motors, Im assuming you have 2 on each speed controller, meaning only 2 controllers needed.

If you wire both left side motors correctly, (for example), to one electronize controller, one or 2 things can happen.

you can connect the motors in series, meaning the 2 motors share the 14.4v under normal running, giving 7.2v each. (this is not always the case, as one wheel may spin for example, then the spinning wheel gets move voltage). Under normal running, this method means the robot runs at a speed that suggests it has only 7.2v of batts on board.

or.... you can connect the 2 motors in parallel, giving 14.4v per motor. The robot runs twice as fast as if wired in series, and has more power, but current is also much higher so be careful.

if you have wired in parallel, run the motors at 150% voltage, setup the controllers right, and charged your batts, the only other ways to get more speed are to...

a) bigger wheels as suggested above
b) pull one stage of gears out of the gearbox
c) remove the ferrite rings on the motor.

all of which reduce pushing power and acceleration.

hope this clears it up.

[psycho_fling]

Sorting out drill motors

the motors are 12volt
the wheels are 75mm

later today ill put some pic on the website of my setup,
ill try some the suggestions and post the rusults

thanks alex

thanks alex

[psycho_fling]

Sorting out drill motors

the pics have been uploaded, hand drawn as my serif draw was playing up

http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk

then robot improvements

if someone could give advicwe now seeing the setup that would be great!

thanks alex

[woody]

Sorting out drill motors

Your motors are drawn as connected in parrallel giving 14.4 volts to each motor..... so you already have the fastest battery/motor setup.
Possible upgrades ..... Increase the voltage a LITTLE .......thatll probably mean new bats.

Replace the motors with 9.6v ones ....Ewan sells some.

Increase the wheel diameter .... But as pointed out this will increase the load on your motors and reduce pushing power.

MY preference ... 9.6 volt motors.

(Message edited by woody on April 04, 2007)

[simon]

Sorting out drill motors

What was the rpm of the motors at 12v ?

[jamesb]

Sorting out drill motors

id agree completely with Woody there, just ask Tony Booth how effective 9.6v motors are on 14.4v. Baromot went for a ride on one of my 2 wheel drive 6kg paytodrives with this setup. 4 of these motors at 14.4v in a 12 kg robot are pretty nippy with plenty of push.

[psycho_fling]

Sorting out drill motors

disaster something has happened, i was testing it without the top working fine, but then tried the top on and it wasnt moving and then i saw white smoke instsntly i pulled the link and investigated, the cause of this was a burnt terminal block which seemed to be conducting on to the aerial. it had melted the terminal block but nothing major seemed to have happened, but i want to check in a mo im putting numerous pics of the pieces on my website can some check if that was the only cause? also the battteries seemed to warm...
the terminal block is smaller than i usaully use, is this a cause?
thanks alex
http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk
robot improvements

[psycho_fling]

Sorting out drill motors

disaster

i was testing the drive and it was fine, so i put the top on, nothing moved then white smoke
i instantly pulled the link a had a look, a terminal block seemed to have melted for some reason. i think the cause may have been the aerial touching a wire then smoking, could this happpen?

im putting pics on my site so if someone could see if there is another cause.

also the the terminal block is smaller than usual and the batteries seemed to be warm?

thanks alex
http://www.psychoflingteam.co.ukwww.psychoflingteam.co.uk
robot improvements

[psycho_fling]

Sorting out drill motors

they are now uploaded, i have also included pics of the normal size terminal block and the protection aroung my batteries

any advice wanted...

alex

[psycho_fling]

Sorting out drill motors

i need to be sure before testing as i dont want to do more damage!

alex

[woody]

Sorting out drill motors

Is your battery negative connected to the chassis?

It appears that the positive wire in the terminal block has shorted out via the terminal block ......I.E. Youve managed somehow to connect across the batteries.

Adding a fuse is a good idea ....especially whilst your playing..... It can eventually be removed.
Your chassis should be isolated from both battery terminls .... check that ALL your connections are adequately insulated .....with NO exposed wiring etc.

[woody]

Sorting out drill motors

This probably makes better reading.....

It appears that the positive wire in the terminal block has shorted out thru the brass of the terminal block .

In my opinion ....Youve managed whilst putting on your lid to connect the positive and negative of your batteries .
Cause ... Inadequate insulation of exposed wires etc.

[simon]

Sorting out drill motors

I would put insulting tape around the block, just to be sure.

[psycho_fling]

Sorting out drill motors

so is this as simple as it sounds? i wont have dome any permenet damage?

thanks alex