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Forum Index : Electronics : Would this drive a F& P?
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
No I mean did the rewired stator run faster than the standard stator? The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| KiwiJohn Guru  Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Um, the fasted stator so far is the one with only 18 coils. I am yet to start wiring for fully parallel on each phase, maybe I should nip down to Repco and buy a metre or so of 7 core trailer wire! |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
I spent a bit more time today messing with various configurations of the F@P stator. One stator has been cut down to just 18 coils ( v:42) and I converted that to each phase consisting of six coils in series parallel (3 coils x 2). 
This is by far the fastest configuration I have ever tested with a top speed of 600 rpm. I need to think some more and decide if further improvements are possible. Of course speed is not everything and low speed torque is probably more important. |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
More playing with my 18 coil stator in the shed today! I found that wiring too many coils in parallel (it was six) produced such a load that the stepper driver went into fault mode and refused to drive it. I put five ohm resistances (nichrome wire) in series but all that did was made a small toaster and no movement from the motor. I tried it with two coils in parallel and the driver would not drive that either. So I took the side cutters and reduced the machine to just 3 coils (one for each phase), almost no torque of course in fact the cogging drag of the other 15 unused coils was enough to stall it at slow speed but I gave it a spin and it took off. I had the driver set for 1500 rpm but I chickened out when I had visions of the rotor flying to bits and pieces of sharp plastic flying past my ears, it was certainly going very fast! Apparently then the driver is happy with a load that has the resistance and inductance of a single coil, presumably the driver would be happy with a series parallel networks of 3x3, that would be 9 coils per phase or 27 for the whole machine. Stay tuned!! |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Re the Fisher and Paykel washing machine motor. I did a test today with the cut down stator and found 2.6 Nm of torque and a free running speed of 500rpm. This is with each phase consisting of 6 coils in a series parallel configuration of 3x2. Considering my earlier tests 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. |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
I wired another stator today, every phase 4,4,3,3 in parallel and it is not a very good performer at all on 55volts 6 amps. |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
I had another try with my latest rotor and managed to measure nearly 6 N.m. of holding torque. It also free runs up to 300rpm. That is using every coil configured every phase 4,4,3,3 in parallel. The three phases are connected in delta. I think it is time to start building the machine. John |
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