I'm relatively new to the site and excuse my post if it is redundant to similar posts. I've built my own Otherpower 10' mill and have it mounted on a 103' tower. Playing around with some other ideas at this point.
Comments on my test methods and or results would be appreciated, even if they involve returning it to the scrap dealer.
I recently acquired the below 90 Vdc motor, made by Graham Magnapak. It is rated at 90 volts, 1200 rpm, 2.4 amps, 1/4 hp. Testing shows that without rewinding or gearing it up, it is probably not usable in my 48 volt system, however may be usable for a 24v or 12v system. The motor is rated for continuous duty and physically measures 10 1/4" long by 4 1/2" diameter (case only) with a 2" long 5/8" keyed shaft and has a 4 bolt rectangular base mount. I have not removed the armature from the case to view the innards.
The following data was obtained by mounting the motor in my drill press, as shown, and operating at belt speeds indicated into a 12v battery pack, a 24v battery pack and into a 48v battery pack. DVM voltage reading were taken statically (drill press off)and under power, from the battery connections and on the motor output leads through an blocking diode. Current is in amps with a multimeter's 10 amp scale. The batteries used are 4 Hawkeye Energy, Genesis Series, G12V120W15SP, Sealed-Lead Batteries (series parallel wired for the 3 different voltages)
On the 48 volt battery pack, 1150 rpms were necessary to produce voltage above battery voltage and thus current into batteries. This may be usable on a 12 volt system or through rewinding the armature, usable on a 24 or 48 volt system. Suggestions requested. No load there is very slight cogging felt. The motor weighs 22 lbs. A few of these may be available in used condition. A bronze bushing is visible on the output shaft versus a bearing. The motor came out of a medical x-ray machine and came with a 1 1/2" cogged pulley on the shaft. ?Possible gear up speed with appropriate blade size and configuration?
12 Volt Battery
Batt V Batt V Gen V Gen V I
Static Powered static powered Indicated
- rpm 12.3 12.3 0.0 11.2 0.0
- rpm 12.3 12.5 0.0 13.36 2.0
- rpm 12.35 13.9 0.0 14.5 7.5
- rpm 12.4 13.85 0.0 14.6 6.75
- rpm 12.6 14.1 0.0 14.7 7.2
- rpm 12.6 14.1 0.0 14.8 7.5
- rpm 12.6 14.5 0.0 15.2 9.0
- Volt Battery
- rpm 24.6 24.6 0.0 11.2 0.0
- rpm 24.6 24.6 0.0 18.9 0.0
- rpm 24.6 24.6 0.0 21.4 0.0
- rpm 24.6 27.0 0.0 27.7 2.0
- rpm 24.7 27.7 0.0 28.3 2.8
- rpm 24.9 27.8 0.0 28.5 3.0
- rpm 25.0 36.2 0.0 36.8 off 10a scale
- Volt Battery
- rpm 49.3 49.9 0.0 36.2 0.0
- rpm 49.3 67.8 0.0 69.1 3.5