# safe max rpm for a DC motor?



## Zemmo (Sep 13, 2007)

I posted this information in another thread. Here is that link:

http://www.diyelectriccar.com/forums/showthread.php/maximum-rpmi-adc-9-26723.html


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## dtbaker (Jan 5, 2008)

Zemmo said:


> I posted this information in another thread. Here is that link:
> 
> http://www.diyelectriccar.com/forums/showthread.php/maximum-rpmi-adc-9-26723.html



very nice... because the 'max' rpm kinda varies with whether you are lookng for extended time, peak, or what. I have an 8", so I am going to assume an all purpose redline of 5000 rpm

I found a nice formula for figuring mph from rpm if you know the gear rations:

mph = (RPM * Rtire)/(G1 *Gf *168)
where G1 is gear selected, and Gf is final ratio

in my case with
RPM = 5000
Rtire = 11
Gf = 3.79

86.38/G1 = mph

1st : G1= 3.58 -> mph= 24
2nd: G1 = 1.89 -> MPH = 46
3rd: G1 = 1.28 -> mph = 67
.... enough!


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## JRP3 (Mar 7, 2008)

I like this handy calculator: http://www.f-body.org/gears/


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## dtbaker (Jan 5, 2008)

JRP3 said:


> I like this handy calculator: http://www.f-body.org/gears/


huh, I just tried to go there, and my browser blocked it and says it has been reported as an attack site that installs spyware without telling you.... i think I'll do my own calculations.


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## JRP3 (Mar 7, 2008)

Weird, I've been using it for about a year, Firefox browser, no trojans, spyware, or virii here


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## JRP3 (Mar 7, 2008)

I just did a google on the site and I think it's a false warning:


> *What happened when Google visited this site?*
> Of the 262 pages we tested on the site over the past 90 days, 0 page(s) resulted in malicious software being downloaded and installed without user consent. The last time Google visited this site was on 2009-02-25, and suspicious content was never found on this site within the past 90 days.Malicious software includes 201 scripting exploit(s). Successful infection resulted in an average of 0 new processes on the target machine.
> This site was hosted on 1 network(s) including AS19262 (Verizon Internet Services).​*Has this site acted as an intermediary resulting in further distribution of malware?*
> Over the past 90 days, www.f-body.org did not appear to function as an intermediary for the infection of any sites.​*Has this site hosted malware?*
> No, this site has not hosted malicious software over the past 90 days.​



http://www.google.com/safebrowsing/diagnostic?site=http://www.f-body.org/gears/&hl=en​


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