12 Volts Pumped Thru Motor!

johnrtse · #1 02-08-2003, 06:34 PM

Well, I'm working on my multi-cell Dragster, and I'm wondering how much juice one of these motors will take.

So.... I made a motor test stand out of a KIT Racing chassis, grab a couple KIT 2.2 and 2.6 motors for cannon fodder, and my variable voltage A/C adaptor for power. The adaptor has voltages of 1.5v, 3v, 4.5v, 6v, 7.5v, 9v, and 12v, all @ 300mA. Please keep in mind that my testing was ultra seat-of-the-pants, so I don't have any graphs or anything.

After breaking in the motors at 1.5v for 2 minutes each, I start to crank up the juice! I ran the motors for 10-15 seconds at each voltage setting, with a 30 second "cool-down" period between "pulls".

The results are as follows; Both 2.2 & 2.6 motors ran at all voltages up to 12v! There didn't seem to be much difference in the motor whine/pinch beween 7.5v to 12v. Torque didn't seem to differ much either at higher voltage (I had gear/axle sets connected- I checked this by lightly applying pressure to the wheel with my finger). I also monitored the heat by keeping my finger on the heat sink constantly (they all got warm at high volts, but at no time did any get too hot to the touch).

The motors all failed by the time I got to the end of 15 seconds on the 12 volt setting (They all ran in the end, but very very slowly).

But the autopsies of the dead motors were surprising. I was expecting to see burnt and fried armatures & brushes, but instead found that the motors didn't suffer ELECTRICAL failure; they ALL suffered ENDBELL failure. That is, the holes in the endbells for the armature shafts were all melted and went oblong from the heat of the spinning armature shafts. The armatures and brushes/wipers all looked ok. Obviously a bushing or bearing would remedy this type of failure.

In conclusion, these motors will run, for short periods of time, at higher voltages. They could be used as-is for short-burst Drag Racing, or for even longer periods if the endbell had a bushing or bearing installed.

I hope you find this interesting. This means that with a transistor mod (to limit the voltage that goes to the PCB), we CAN send as much as 12 volts to these tiny motors!!!

John

Project RC · #2 02-08-2003, 10:20 PM

Did you run the 12volts straight to the motor or did you connect the batteries to the PCB then to the motor?

johnrtse · #3 02-08-2003, 10:29 PM

I used a KIT Racer to make my motor test stand, so I did not use a PCB in this test. Anything more than 5 or 6 volts thru a PCB can fry it.

A person using more than 5-6 volts would have to use the transistor mod to send only minimum voltage to the board, while sending max volts to the motor.

John

Namuna · #4 02-08-2003, 10:49 PM

VERY interesting results johnrtse!

Moving on over...

#5 02-09-2003, 12:42 AM

There are slot-car bearings you can use. Heard there expensive but damn I think their small enough.

johnrtse · #6 02-09-2003, 08:20 AM

Come to think of it, I remember someone posting a link to a website that did have a motor with BEARINGS! It was only rated a 1.0 (10,000 rpm) motor, though.

But with 12 volts pumped thru it......

Here it is!

http://smoovy.com/en/mps/brushless_s...blbs5001r0.htm

John

mattsx2005 · #7 02-09-2003, 10:12 AM

i uh pumped 330V @150mA though a motor while it was still attached to the car and blew one of those lil black chip thingies on the board and made a big spark

johnrtse · #8 02-09-2003, 10:18 AM

Step...away...from...the...car!!!!

Where did you get that kind of power supply? (330V)

mattsx2005 · #9 02-09-2003, 10:33 AM

from a camerra flash thingie ok and it is 150mA so it doesn't have that much current

mattsx2005 · #10 02-09-2003, 10:36 AM

i mean it had enough current to blow the chip but i mean i've zapped myself with it plenty of times

johnrtse · #11 02-09-2003, 11:08 AM

Oh, And in case you were wondering what the point of all this is.

My Dragster/Pro Stock project:

Here is a link to the transistor mod site- which this car will also be getting:

http://wdiaz03.tripod.com/minidragster.html

mattsx2005 · #12 02-09-2003, 11:12 AM

wat is the bit char-g website

ph2t · #13 02-09-2003, 08:56 PM

holy S@#& !

Dude, I noticed in you pic that you have soldered several batteries together. Just be carefull! The rechargables do not like high temperatures at all so I would be very carefull in how much time you spend in soldering the wire to the battery terminal.

You don't wan't the thing to explode and cause some serious injury.

What I do is slightly file/sand back the battery contact and pre-tin a tiny bit of solder to the terminal. I then pre-tin the wire and then re-solder the two together. After that, straight into the freezer the battery goes!

be carefull!

ph2t.

Nathan · #14 02-09-2003, 11:29 PM

You could just use a 9-volt battery and the transistors. Or better yet, two motors w/ two or three bats apiece, and one for the PCB. Imagine the possibilities...

skater252000 · #15 02-10-2003, 12:11 AM

Quote:

Originally posted by mattsx2005
i mean it had enough current to blow the chip but i mean i've zapped myself with it plenty of times

Dude thos flash batteries are so ****in strong. They made my whole body shake when I got shocked from em. Was it that bad for you?