In short (since I lost the original post) I'm testing my 1/2 HP ECM conv. that fell of its purch last spring
This is an 18 coil ECM (6 coils per phase, 3 phase), that is used to charge into a 600 amp/hr 12 volt bank.
Bench Tests were done using a VSR 6.6 amp drill (controlled by rheostat) belt driving the unit. ECM to ammeter to 1 12 volt batter at ~80% charge. Great way to kill a drill but I didn't)
3 different wiring schemes tested
- Parallel Star. Each coil in each phase wired parallel. Stops wired into star point , starts rectified to battery
- Series Parallel. 3 coils in series parralel to next 3 coils in series (for that phase). No star , straight to rectifiers
- Series. 6 coils in each phase series , no star, rectified
Results:
note. Max RPM obtainable RPM of the drill changed based on wiring scheme, the more the coils were in series, the higher the load, the less RPM achieved at MAX
- High Startup (500 rpm), higher current at max RPM.. This is how I had it wired while running
- Greatly reduce startup(320 rpm), still a decent current at max RPM
- Even more reduced startup(180 rpm), lower max current at max rpm
End of story.. will rewire using scenarion 2.
Test setup
Data. Left is Amps, bottom is RPM