kfong wrote:Burtie, how has that gearbox been holding up? I looked at the specs and see that it's happy at around 4000rpm. I was going over the numbers and was surprised you reached 40mph. The kv of the motor is much higher or I must be off on my calcs. Does the gearbox get hot at all? I'm thinking of doing the same but want to be sure that the gearbox can handle it. You seem to be pushing it beyond specs.?
Burtie's running a Neugart PLE80 20:1 planetary gearbox. According to the manufacturers specs these are rated to;
Max Input speed - 7000rpm
Output Torque nominal loading- 120Nm
Output Torque Shock loading - 192Nm
Radial loading - 650Nhttp://www.neugartusa.com/Produkte/ple.html
Burtie's running a 1:1 pulley system from his 80-100 to the gearbox input, so maximum nominal torque advisable to have the motor produce is 6Nm steady state, 9.6Nm peak.
To produce a constant 6Nm of motor torque with a Turnigy 130Kv 80-100 you would need to supply the motor with ~81.7Amps phase current steady state
. Peaks/spikes of phase current up to ~131Amps
would be the limit of the manufacturer recommended gearbox shock loading for Burtie's setup.http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=25094#p362274
At 6Nm steady state input torque, this gearbox/reduction combo can handle up to 4.4Kw @ 7000RPM. Running a 130Kv version Turnigy @ 44V nominal 12S lipo, Max power output potential
occurs around 2860rpm (1/2 No-load speed = equilibrium point between BEMF&efficiency), but advisable current input at this point is limited by gearbox torque rating. Efficiency improves at higher RPM, but torque diminishes, so i'm thinking most people use ~50>85% of no load speed as the usable powerband. Staying right on the 6Nm/~81.7A (phase current) limitation means a safe usable ~1.8kW > 3kW between 2860rpm > 4862rpm @ 44V
[in theory]. What sort of numbers are you seeing Burtie??
I'm not at all surprised Burtie's gearbox is holding up so well, it really is sized very well for his application in terms of size/weight/reduction vs output torque capability. And to top it off, he got it at a liquidation price. Lots of us are envious....