RE: (ET) Elec-Trak ZTR

["" <thumphrey mynra com>]

 OK I did that......kind of.
  
 I "assumed" a tire diameter of 23" for my I-5. (I'm not home right now)
  
 The I-5 published top speeds are
  
 LL - 1.2 mph
 L - 3.6 mph
 D1 - 6.5 mph
 D2 - 9.5 mph
  
 which align very well with Mikes counting of final drive ratio.
  
 The result is a motor RPM of right around 4700.
  
 I hope my tire size assumption is incorrect. Because I'm using an E-20 
drive
 motor to power my sawmill, and I had figured on a top speed of about
 3500RPM. I suppose I could run it backwards thus using the series field to
 slow it down....naaah.  I'll just change the pulley size
  
 Hmmm...a 21.5" tire gives us a 5000rpm motor.
               a 30" rear tire gives 3600 rpm.
  
 Anyone know right off hand how big the rear tire diameter is on an E-20 or
 I-5. 

Stay Charged!
Hump
  
 
> -----Original Message-----
> From: elec-trak-bounces cosmos phy tufts edu
> [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Ralph G 
> Vogan
> Sent: Monday, July 12, 2004 2:45 PM
> To: Elec-Trak
> Subject: Re: (ET) Elec-Trak ZTR
> 
> 
>     If you know the top speed of the tractor you should be able to figure
> the RPM of the motor at that speed in D2.  Calculate the number of feet 
> it
> travels in 1 minute at that speed (FPM);  5280 X top speed then divided 
> by
> 60 = FPM.  Measure the exact distance your tractor moves for 1 
> revolution of
> the back wheel (It dependes on the size of the tires), and divide that 
> into
> the FPM.  This is the RPM of the drive wheel.  Multiply the wheel RPM by 
> the
> gear ratio of D2 to get the MOTOR RPM at that speed.  
>  
>     By working backwords you can get close to the top speed in the other
> gears using their gear ratios.  Allthough the motor may run a little 
> faster
> in those gears because it has less load on it.  
>  
> Ralph V
> ralphgv centurytel net <mailto:ralphgv centurytel net> 
> 
> 
> ----- Original Message ----- 
> From: Elie, Larry (L.D.) <mailto:lelie ford com>  
> To: Mike Wallace <mailto:metman glasgow-ky com>  ; Elec-trak Discussion
> Group <mailto:elec-trak cosmos phy tufts edu>  
> Sent: Monday, July 12, 2004 11:00 AM
> Subject: RE: (ET) Elec-Trak ZTR
> 
> Good job.
>  
> Related question; but with the motor speed and tire diameter one could
> figure it out.  Does anyone know where there is a list of 
> nominal speeds for each gear, and motor speeds for each of the forward
> positions for E12 and E15?  There is overlap of 
> course, but I would like the real numbers.  The only ones I have ever 
> seen
> was 'top-speed' (D2) and assuming it is max motor 
> speed.  With these ratios, I can now tell what max speed in each gear is,
> but I still haven't a clue as to motor speed at each 
> throttle position.  I don't really want to go to the trouble of a fancy
> tachometer, and there should be a chart somewhere.
>  
> Larry Elie
>  
>  
>     LL - 266:1
>       L -   90:1
>     D1 -  50:1
>     D2 -  34:1
>  
> 
>