Brought down my treadmill motor last weekend to swap out the blades etc.
previous post(
http://www.fieldlines.com/story/2010/1/24/957/57415) for pics with the new blade set
The treadmill motor is a substantial Baldor, 2400rpm/90vdc/21amp. When I initially put it up 3 weeks ago, I used 3 regular hornet blades (56" swept) on a small aluminum hub I had lying round. With that configuration it was just taking too much wind to start up, even acknowledging that these smaller units usually do.
My bench tests had shown a cut-in of about 400 rpm at 12.5 vdc, so I knew I could get power out of it if could just get it to spin up so I made the following changes.
In the past I have had pretty good luck using a 6 blade configuration on ECM conversions. The six blades are 28" hornets cut back to 22" .
I used the 6 blades this time, on blade extensions off the hub to get a final diameter of 52" , and I increased the weight of the hub using a steel one of about 5 lbs.
The effect of the changes was dramatic, It now starts up easier and will run longer, probably partially due to the increased weight of the hub getting past the friction of the brushes.
Overnight last night I saw a peak output of 14.1 Amps at roughly 12.5 v, higher than I expected to ever see (no wind data, but hasn't been over 20mph I don't think ). So I'm actually happy with the unit.
