All right, I'll offer a SWAG (swinging wild a-- guess, for those not familiar with "engineering terminology"):
The difference in noise could be cause by differences in harmonic vibration. A two pole motor like a Novak will have fewer but relatively larger (meaning greater percentage of a revolution) power pulses per revolution than a 4 pole Neu, Tekin, or Castle. So a Novak powered car could be louder than a Tekin/Castle/Neu powered car with the same gears. That would be an interesting experiment. Different size rotors could also affect the torque pulses. Remember that these motors cannot provide smooth torque like an 8 cylinder auto engine because the field coils are being switched on an off to provide a rotating magnetic field.
When you change pinions, you alter how the harmonic torque pulses from the motor are imparted to the spur, so you change how the sound is produced. One spur/pinion combo could be imparting pulses to the spur at a frequency different than its native harmonic (think tuning fork) and so the vibration doesn't build up. A different spur/pinion combo could be imparting pulses that match the harmonic frequency of the components.
Verifying this theory would require a large assortment of different spur and pinion sizes and we don't have such an assortement for our 1/8th scales.
Now, if you believe all the mumbo-jumbo, I have a bridge here somewhere for sale....
BTW, "properly meshed" to me has always meant as close as possible without binding anywhere in the rotation. I would never have considered trying to make it looser to change how much noise it makes. I find it interesting that it reduced the noise. I would have expected more noise with looser mesh.
Catching up on my reading and just saw this post...now, the question I have is does the change in harmonics going from a two pole to a four pole motor affect the cyclic stresses that need to be overcome on the pinion setscrew when changing motors? For example, should I just spot weld the pinion to the shaft when going from a Tekin to a Novak?
I had no idea you were an engineer Mark. Which railroad?
__________________
Gary
GMK Supply
www.gmksupply.com
Great products. Goofy names.
Another way to look at it.........If you use say a 48/12 that = 4 an even # so the pinion runs in the same place on the spur and can make more noise.
With say a 48/13 that = 3.6923076 an odd # so the pinion runs in a different place on the spur and can be quieter.
If you use an even # there can be more harmonic vibrations generated.
Dose that make sense or am I wrong ???
At some point the last time I raced it I must have but the 12T pinion in it, it is in fact the 12 that was loud. I race at WCRCR last nigh and wanted to lower it thinking it was the 13 and ended up with the 11T pinion on the 48 spur with the mesh set nearly as tight as I would with 48 pitch and it was quieter than the 12T. I don't do paperwork very well.
I never know how fast the guys are I race with or for that matter how fast I am but with the times from last night and the race last week I am left wondering what Novak engineers were thinking when they came out with their 1/8th scale motor line up?
With the nearly the lowest gearing I can run 11/48 and the big arm in the 6.5 I have to wonder what you would you ever use a 5.5 or a 4.5 for? 3S or 2S?
Catching up on my reading and just saw this post...now, the question I have is does the change in harmonics going from a two pole to a four pole motor affect the cyclic stresses that need to be overcome on the pinion setscrew when changing motors? For example, should I just spot weld the pinion to the shaft when going from a Tekin to a Novak?
I had no idea you were an engineer Mark. Which railroad?
No. You still need to have the pinion on tight enough that it doesn't come loose.
Why would you use a Novak? You need to excercise your spot welder?
Grand Canyon Railway: http://www.thetrain.com/ - I rode on it once. No, twice (once each way). So I was an engineer on the train.
Today was a really nice day, wish I could have gotten one more run in for the year but the track was still a lake, I did get my new body and wing installed.
__________________
Team Fast Manager
Team Losi
Team Novak
Smc batteries
Not a team terribles member
Delta vs wye windings, I prefere wye, if it suits your application.
The Stator windings are connected in a 3 phase triangle pattern for delta vs. a Y looking connection for Y.
hey thanks, so what is the difference in power characteristics?
I know in 415v ac its, y for less starting and delta for running, so i guess y for lower revs and delta for higher revs?????????/
hey thanks, so what is the difference in power characteristics?
I know in 415v ac its, y for less starting and delta for running, so i guess y for lower revs and delta for higher revs?????????/
you got it! But with all the power these motors make theres really not a blatent difference.
__________________
losi 8 T8 2250 "T" MMM
losi 8T 2.0 T8 1550 MMM
hobbycity zippy packs
try em out they arent bad!!!
rcproduct designs rocks!
Thanks Nick.
Thanks to Tom F for all his hard work on it.
The dimensions for the EL8 tray are now 170mm X 49.5 mm
Battery of choice at this time is the Turnegy 4s packs. They are very well priced and seem to be holding up really well in race conditions.
Big Greg... any input on the batteries?
LXMuff???
For those of you using the Turnigy packs, have you been cutting the wires and soldering your preference of connector? I looked at them on Hobbycity and the connectors they have on the batteries look weird i do want to pick up a couple and was wondering if they were worth it?
For those of you using the Turnigy packs, have you been cutting the wires and soldering your preference of connector?
Yes, but not cutting the wire to keep it at the max length. I peel back the shrink wrap and unsolder the included connectors. You can then use your connector of preference. For years I used Deans but feel for 10g they are underrated and annoying to solder to that gauge wire. When I ordered the Turnigy packs I also ordered some EC5 connectors. They are 5mm bullet connectors inside a plug. They fit the 10ga wire perfectly and are easier to connect and disconnect. Best part, half the price of Deans.
Quote:
Originally Posted by tom2tone
I looked at them on Hobbycity and the connectors they have on the batteries look weird
The Turnigy packs come with 5.5 gold bullet connectors, one male and one female. You can buy the connectors from Hobby King and keep them on the batteries, or follow my advice above.
.
Similar Threads