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| John Hill:
Too many coils in parallel is a bad idea, :coffee: with 6 coils in parallel the resistance is only 0.3 ohms and the driver shakes it head when presented with that load. |
| John Hill:
Just three coils, one for each phase, runs very fast, so fast I chickened out and did not take it to the maximum fearing the rotor will fill my workshop with flying bits of plastic and small magnets. :zap: So what can be gained from this information? Obviously there is nothing to do with the characteristics of the individual coils or magnet circuits that prevent high speed operation and also obvious is that the controller and driver circuits can drive to high speeds. The challenge now is to arrive at a configuration that is optimum for this combination of F@P and these driver bits. |
| vtsteam:
:coffee: :coffee: |
| John Hill:
I did a test yesterday with the cut down stator and found low speed torque 2.6 Nm (about 350 ounce inch) of low speed torque and a free running speed of 500rpm. This is with each phase consisting of 6 coils in series parallel configuration of 3x2. Considering my earlier test I believe this is the most practical configuration for this motor with the power supply and drivers I have on hand. Considering also that I am using only 18 of the original 42 coils I expect more powerful drivers would get at least 5.5Nm of torque, maybe more. If I were to add more coils that would mean more in series which would reduce the voltage across each coil and increase the inductance. The drivers say they are good for 60 volts, 8.3 volts peaks and 5.9 volt rms, maybe if I stub my toe on a 50v transformer! :coffee: |
| vtsteam:
Two matched 30's with secondaries in series would get you 60V. But you have to phase them properly or you won't get any voltage. I've done the same to increase current capacity instead by parallel connectingl, but then you ABSOLUTELY must get the phasing right, or it's a short circuit for both. :zap: |
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