Shop our Airplanes Products Drone Products Sales
Thread Tools
Old Mar 29, 2010, 09:00 PM
south is offline
Find More Posts by south
Registered User
Discussion

Can we calc amps if we know rpm/vots


Here is a math problem:

Unloaded the motor's kv is 485. Using 10S we have a max rpm of 20,370

When used, max speed was 57mph using a prop pitch of 4.43 which means (assuming 0% slippage or loss) an rpm of 13,587 (how many times 4.43 inches needs to be multiplied to reach 60,192 inches that 57mph moves per minute).

If the math and logic above is correct, can someone tell me how to calculate the amps drawn due to the drop in rpm from unloaded 20,370 rpm to a loaded 13,587 rpm?
Sign up now
to remove ads between posts
Old Mar 30, 2010, 01:09 AM
CornelP is offline
Find More Posts by CornelP
Registered User
CornelP's Avatar
...look for fecalc, you could get the results you're after.
Old Mar 30, 2010, 03:46 AM
CornelP is offline
Find More Posts by CornelP
Registered User
CornelP's Avatar
In case you don't have it, this is the most up to date version. If your motor is not listed, open the text file and add the data. The instructions are quite clear.
Old Mar 30, 2010, 07:10 AM
ozzie-crawl is offline
Find More Posts by ozzie-crawl
Registered User
a good thing i do if not using a data logger, time your run then recharge battries
see how many mah have been used, then go to this link http://www.offshoreelectrics.com/conversion.htm at the top of the page you will see average amp draw calculator. put in how many mah used and run time this will give you a average amp draw threw that run,if using this its best to have a short 60 sec run flat out out, its important the timing be exact


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Can you tell me if we can charge this? airmcn_3 Batteries and Chargers 5 Feb 01, 2010 06:07 PM
Discussion Hey, if they can be undocumented, why can't we? MtnGoat Life, The Universe, and Politics 84 Apr 30, 2006 08:21 PM
Anyone know if AXI2208 series will handle 4S, or max RPM? wilsonj Micro Helis 9 Mar 23, 2005 04:08 PM
Anyone know if AXI2208 series will handle 4S, or max RPM? wilsonj Power Systems 0 Mar 14, 2005 06:34 PM
Question Can some one help me??? I dont know if I can do this? gbison Micro Helis 7 Jun 14, 2004 04:31 PM