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"Most Efficient" operation is
obtained with full field voltage.Any field weakening will result in a
corresponding increase in current demand by the armature.
Depending on the loading, and the batteries' ability to sustain this
increased demand without a large voltage drop would determine just how efficient
weakened field operation would be.
I've always
viewed field weakening as a trade off, like sacrificing Torque, {Efficient
Operation}, for Horsepower{Inefficient Operation, Higher Speed.}
The more technically educated Listers
may now fire away. <G>
----- Original Message -----
Sent: Thursday, October 21, 2004 8:55
PM
Subject: (ET) Safe E20 RPM
I?m continuing on my fun filled
project of installing an Alltrax Inc DCX
300-ET controller in my E20. My main motor brushes and bearings checked out OK
for further use. With the help of many of you the conversion is about finished
except for connecting the lights and PTO, wire dressing, securing, and closing
up. Will someone now tell me the rpm range of the E20 Elec-Trak motor? I have
searched the Digest but have not found where anyone has published actual motor
rpm numbers. Some one advised that mowing should be performed at an rpm which
is not excessive and at an efficient level to avoid damage to the main motor.
I actually want to experiment with a resistor of a size that may maintain a
safe and efficient main motor rpm while cutting the grass. I use a digital
photo sensor tachometer for accurate rpm measurements so I reasoned that if I
knew the safe long term running speed of the motor the best resister size
could be determined. When that size is found I will set up an alternate speed
control dedicated to mowing. What is the maximum speed that may be considered
too high? Someone wrote ?do not rev the motor too high? or it will fly
apart or something bad will happen. Any comment you make will be appreciated.
Thank you, Raymon
Ellis
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