RE: (ET) Safe E20 RPM

["Markus Lorch" <mlorch vt edu>]

> 
> There were several replies, but no one has given any RPM 
> numbers. I really 
> would like to know these numbers, as I am helping my grandson 
> convert my extra 
> New Idea parts tractor to be driven by a small gas engine (a 
> Reo engine, of 
> course).
> 
> If I knew the working RPM range of the original motor it 
> would be a lot 
> easier to figure out the drive train between the gas engine 
> and the transmission.
> 
According to the motor power curve that Mike Wallace made available to us
for
the motors built into E20s (see http://www.econogics.com/ev/e20pwcrv.jpg)
the max. RPM of the E20 motor with no load and full field is at 2500 RPM.

Now we know that under normal operation the drive motor current usually
stays way below 100A - if I am reading the schematic right then the motor
RPM with full field
will not dip below 2000 RPM unless more torque than the 11 ft-pound 
delivered are required (and thus more amperage than 100A drawn)

the max. RPM with full field weakening is 4900 RPM but unless only very
little
power is required the motor cannot sustain that speed. E.g. at a resonable
5ft-pound of torque requirement the RPM will already be down to about 3200
RPM ...

So in summary I think the typical RPM range is between 2000 and 3000 RPM

No guarantees - I could also be way off here...

Markus