Motor current draw findings... - Page 3

mystiquesupra · #31 01-05-2004, 02:20 AM

What size wire is on the sb motor and stage 1/2 motors?

Can these be un-wound, and then re-wound with the desired wind count with out damaging the wire.

Or is it best to use new wire from the start?

Joey · #32 01-05-2004, 06:00 AM

I don't see why there'd be any difference in using the original wire, as long as you took extreme caution not to damage it in any way. Short of breaking it, I don't even know how you'd go about hurting it anyway.

neurokinetik · #33 01-05-2004, 08:39 AM

Quote:

Originally posted by TypeZer0
would winding it twice at 21 turns effectively make it a 11.5 turn motor?

It draws as much current as an 11.5 turn motor, yes, but generates the magnetic field of a 42 turn motor. Should give high speed and high torque.

Quote:

Originally posted by Joey
Alright, this has been bothering me since I started coming here: does a larger amperage draw necessarily mean a higher power output?

Only if all other things are equal. Look at how low the current draw is on the 180 motors, yet they outperform every 130 motor I have made so far. In general, though, more power in should yield more power output from the motor.

Quote:

Originally posted by mystiquesupra
What size wire is on the sb motor and stage 1/2 motors?

Can these be un-wound, and then re-wound with the desired wind count with out damaging the wire.

Or is it best to use new wire from the start?

SB Motor: 34Ga
Stage 1: 32Ga
Stage 2: 30Ga

You could re-use the wire, but it is harder to get it wound tightly when it has kinks in it from the previous use. Plus you will have to cut it where it attaches to the commutator.

TypeZer0 · #34 01-05-2004, 12:09 PM

silver conducts electricity better but obviously it's gonna be a bit more expensive than the more common copper

FastRSX · #35 01-05-2004, 08:18 PM

neurokinetik where did you purchase the Yeah Racing ball bearing motor can?

neurokinetik · #36 01-05-2004, 10:42 PM

Quote:

Originally posted by FastRSX
neurokinetik where did you purchase the Yeah Racing ball bearing motor can?

Dinball RC Mart.

http://www.rcmart.com/catalog/defaul...Path=144_21_80

They have one motor can that just comes with ball bearings (probably one of the best cans, IMO.) but no magnets or brushes, and then they sell one that is pretty generic but has thin Neo magnets and carbon brushes.

As for motors wound with silver wire, well, that would certainly be interesting, not to mention expensive. In theory, you wouldn't need as thick a wire with silver due to the better conductivity over copper.

neurokinetik · #37 01-06-2004, 06:25 PM

Tried the 21 turn double in a car, and it was dissappointing, but not as bad as others I have tried (IE 25 turn single, Plasma Dash) On the speed checker, it hit 21kph, and that is with the 8 tooth pinion. Acceleration was not so good, taking at least 5 feet before it really started to move. Oh yeah, and that is also after I swapped out the spin brush magnets for thin Neos. The motor runs quite hot, and the FETs started heating up after a minute or so as well.

Oscilloscope will be here tomorrow, but I'll be too busy racing to do RPM testing. Hopefully Thursday night I'll get cranking on that.

boxcrash · #38 01-06-2004, 07:59 PM

I have a Oscilloscope at work on the test equipment as well as many other tools, all digital as part of our Seimens Diag equip.

I have not even tried to use it in this way yet but have planned to, maybe now I will get onto that.

Also I am curious as to what the magis ESC current draw number is and I know no one knows....anyone know a engineer who helped create these or is there anyway to find out???

neurokinetik · #39 01-07-2004, 12:03 PM

I suppose it could be found by sacrificing a couple of the stock FETs. Run for about 30-40 minutes at a set current level, if they don't smoke, let them cool off and start again at a higher current level. Repeat the test until they smoke.

You'd need access to a regulated power supply with an adjustable current limiter. Run the FET output to a very low impedance load, and use the adjustable current limiter on the supply to set the current level.

I don't have such a supply at the moment, and have no great need to buy one. Plus this testing would be time consuming.

boxcrash · #40 01-07-2004, 12:24 PM

true that would work and require alot of time.....

Not that I want to fry some FET's up though.

Have you ran the stock Plasma Dash on a stock XMod for a long time??

I have a motor I am curious about that when measured on 10amp scale pulled a steady no-load .70 amp(700 miliamps) @ 8.5v aprox on a 9v battery that was at 8.8v before load test.
It did jump to 2.0 amp max when the juice was first applied to it and leveled off at .70 consistently.

Just wanting to find out if this thing will be a stock FET smoker.

ahedofu · #41 01-07-2004, 02:45 PM

neurokinetik

this is kinda of topic but isn't rcmart in hong kong.

I was wondering how long it took the cans that you ordered to get the states (to your house)

Thanks
Richie

boxcrash · #42 01-08-2004, 12:39 AM

Crap.I typed a book........ and accidently changed the page before I hit submit...

Ah well I used a primative method to check the motor I have described above for RPM's at 3.6v.
A microphone and my computer using Sound Forge.

Recorded the motor spinning and clicking a piece of flexiable plastic against the pinion in a homemade motor stand @ 3.6v.
I counted the + in the waveform in the software at .100 seconds which I multiplied by 10 then multiplied by 60 then divided by 8(number of teeth on test motor pinion).
Which gave me 24,225RPM's under no load other than that small plastic piece.
So @ 7.2v I would have 48,450 RPM's under no-small load.

Which is about right because I tacked down manufacters motor site and used there graph and specs and got 7.2v=48,600 RPM's at 25* C which RPM's and efficency increase with tempature up to 80*C. Which I imagine like computer after that it drops and you have looslesness or whatever and loose gains. Like the 130's feel like 130*C + under 30 minutes load so I know there is lose.

yeah so anyhow that seemed to give me a roundabout aproxmation of RPM's. I might still get a laser meter.

And yes RC Mart is in Hong Kong and I have heard it takes 4-8 days to get a package from them.

neurokinetik · #43 01-08-2004, 12:05 PM

Quote:

Originally posted by boxcrash
true that would work and require alot of time.....

Not that I want to fry some FET's up though.

Have you ran the stock Plasma Dash on a stock XMod for a long time??

I have a motor I am curious about that when measured on 10amp scale pulled a steady no-load .70 amp(700 miliamps) @ 8.5v aprox on a 9v battery that was at 8.8v before load test.
It did jump to 2.0 amp max when the juice was first applied to it and leveled off at .70 consistently.

Just wanting to find out if this thing will be a stock FET smoker.

Plasma Dash WILL FRY YOUR STOCK ESC! With a set of four NiMH AA's, it was drawing 1.7A continuous. The Mini-Z guys all stay away from it now after melting both FET stacks and extenal turbos with it. I ran one in my car for a minute, but the performance was so poor in an XMod that I scrapped it for parts pretty quickly.

Using a 9V to measure current is not a good idea, as they don't put out the kind of current that a set of NiCd or NiMH AA or AAA batteries do.

Mr BigShot · #44 01-08-2004, 12:22 PM

Just a Quick ? It maybe a dumb ? also but in my Highly supped up "Team Orion Big Block supra "i still have stock Fet's if i stack 2 or 3 Fet's will that make it a lot faster ? It all ready fly's but more speed is all ways better

neurokinetik · #45 01-08-2004, 12:23 PM

You probably won't see much difference in speed from a FET stack.