Fisher and Paykel motors

[whatever]

if your neos were touching the iron core anywhere that would lock it up, need to have a tiny gap between the coil core and the magnet faces. Also fp motors do have cogging but this can be reduced by filing off the edges of the iron core where they exit the coil ( thats been discussed for many years)
nice link
one note on fp motor controllers: it may well be possible to run an fp motor ( as a washing machine ) on a low voltage source,
by changing the fets, never tried it, but pretty sure would make a great low volt dc washing machine

[whatever]

just reading up on what some windgenerator guys are doing to reduce cogging,
here is one solution ( slanted magnets)
http://www.mindchallenger.com/wind/wgpage3.html


also another solution below for zero cogging but involves 7phase rewire so wont work with 3 phase controllers
http://www.thebackshed.com/Windmill/articles/coglessFP.asp

[zt3]

Actually, we provided a 1mm air gap between the neo mags and iron core.. Still the same result - the motor couldn't spin by hand... Anyway, we haven't considered decogging the stator as we haven't had enough time doing it. But we're pretty sure it would increase the motor efficiency by a significant figure. Here are two other tips that could reduce cogging of FP motor - http://www.thebackshed.com/windmill/art ... gingFP.asp

Another thing I'm concerned about is the power supply. What type are you using? Battery or bench type? We wanted to reach the potential of our motor but running it at 48V left us with a maximum efficiency of 26% under maximum speed of 770rpm with load. Our Lyen controller could accept up to 88V and deliver a maximum output power of 3500W. Any suggestions how we could obtain that amount of power? BTW, we're currently using 2 Cosel P600E-24 connected in series, which gives us a 48V, 1300W of power.

[whatever]

it looks like your cogging is a very big issue, it was maybe 10years or more ago when I was messing with fp motors.
ebikes in china were just beginning and there weren't controllers available, hence I built my own, my efficiency was also very low, amp draw was high, but it was free spinning ( i was using the ceramic mags and just rewired in parallel)
I ran on 36v from memory. My power source at the time was a briggs and stratton ( 2hp??) engine running a old tape motor as a gennie, which charged up two lots of sla battery strings ( 36v 18ahr each).
It was a three wheeler with no fairing. I did have alot of headaches with the home built controller ( blowing fets mainly).
You may or may not be aware of a guy selling a123 cells 20ahr pouches on ebay ( from china) , they are seconds but from what I hear they are quite good capacity. You can pick them up via china very cheaply if you have chinese contacts ( about half price of what the ebay guy sells them, exact same cells, but you need a chinese contact to do that, if you want any help with that I can assist privately).

On the cogging: do you know the dr eck motor used in ultralights? ( german), its almost identical to the fp motor ( no coincidence I think), the difference being his iron fingers ( coil laminations) are shorter than the fp, that might be how he has reduced cogging ( but I haven't found any really detailed info on the motor to confirm any other changes to reduce cogging). You should be able to get up near 85% efficiency if you can overcome the cogging issue, there may be some other factors contributing ( such as winding resistance etc) but thats a bit beyond my skill.

If shortening the iron fingers is a way to reduce cogging, then it would be possible to glue neos over the old ceramics and reduce diameter of motor by shortening fingers, but would require rewinding the poles, it might be hard to glue directly onto the old ceramics also.
It might be worth checking with mathew in melbourne ( username: f&p ) on his cogging. I've never tried to put neos into an fp motor, but its something I need to do in future for a project I'm working on. So i'm very interested in your work.

[whatever]

i think twisting the stators will be easiest way to reduce your cogging, maybe no need to file off the edges.

[zt3]

Gee thanks for the info! Lots of sources indeed! I and my thesis mates are still on the process of analyzing the performance of our FP motor. And yes you're right! Cogging is really a big factor in our prototype. The simplest way to do is either file off the edges or skew the stator slots. We'll probably recommend it for future work as we haven't got enough time to do it. As of now, we have achieved a 30% efficiency at 48V controller supply, drawing around 17A(rms) in controller output. The motor is under load by applying a mechanical brake. Is that reasonable enough? Will increasing the power supply to 88V (max of the motor controller) would further increase efficiency?

[Samd]

+1 Subscribed.

My dad is retired from 20 years of Washing machine repairs but still has lots of parts. I have four in my workshop, 0.6mm up to 1mm, and the new generation decogged magnets from the factory.

Let me know if you need parts or pics...

[DarylMc]

Hello everyone
I stumbled across this forum and it is a very interesting source of information.
Right now I am trying to run a Fisher Paykel motor from a brushless DC industrial drive.
It supplies 5V for the halls and has 3 connections for the outputs.
I am using the standard hall board for the motor but I cant measure any output when I rotate the motor by hand with power applied to the halls.
The motor has no motion and locks.
I've tried swapping the hall sensor board and same result.
I am getting 3 different voltages on the hall outputs 5V- 1V- 2V but they dont change.
Does anyone have any suggestions which could help me get some outputs to the controller from these boards.
The drive also has a jumper switch for 60 degree or 120 degree sensor phasing but I dont know which the FP board would be.
I have seen an led tester for the halls which runs on a 9V battery so I assume they will work on that but if anyone knows what voltage range to use I would appreciate it.
Or perhaps what I might need to do to modify the halls.
Thanks

[DarylMc]

I'm sure the picture in the post on the previous page was wrong regarding the FP Hall Board wiring.
I have the motor running now.
But too much current for some reason and it's heating the windings too much so I'm off to investigate.
The picture attached is the correct wiring.

[whatever]

what voltage are you running?
have you made any mods to the fp wiring?
they are wound to run on a certain voltage ( which I cant remember off top of my head) it was pretty high
rewinding them into parallel connection they make a good low voltage motor, but not modded they need a pretty high voltage
as a generator just turning by hand you can easily get up near 100v output if unmodded

[DarylMc]

Just reversed the motor direction and it dropped the current right back

[DarylMc]

Hi whatever
It has standard windings and 240V controller.
240V and 0.7A per phase on the motor right now.
There is a massive difference in current depending on the direction of rotation which I assume is due to the positioning of the hall sensor.

I've been using FP motor in a centrifuge for the last 8 years.
It spin dries a large basket of washed lettuce leaves at 600 rpm for one minute.
Previously I couldnt find a suitable brushless DC drive and I was running it without hall sensors from a VFD with careful tuning to allow it to grab sync at startup.
With that arrangement it had virtually zero torque at startup but once it started moving it was fine.
Despite one drive failure during that time it worked really well but I never could get it to run on anything other than the very early motor with small magnets.
I found this brushless DC drive and wanted to give it a go with a more readily available motor.
http://www.baldor.com.au/product_view.php?PROD_ID=154
All seems good now with the standard FP hall sensor.
Fantastic low speed torque and more than enough for its task.
Fingers crossed it will give a good working life.
Thanks for the reply.

[whatever]

thanks for reply, if you ever want to go to low voltage ( 48v) (you can use ebike controllers....dirt cheap) but requires reconnecting windings into parallel ( a bit of a job) thats very interesting your using it on high voltage with low amps ( exactly what it was designed for)

[DarylMc]

If anyone is interested.
With the particular Baldor drive and a FP 42 pole stator with 14 segment 56 pole rotor, I hit a limit of 430 RPM.
Rewired the stator from star to delta and now I have much more rpm available.
Still running an acceptable 1A per phase @ 600rpm with the small load of the centrifuge.
I also tried a later model FP 36 pole stator 48 magnet rotor motor expecting it to have higher rpm but it had less.
I now put this down to back emf not allowing enough current to flow in the windings.
The later model 36 pole motor with rounded iron poles was much quieter but I didnt try connecting it in delta.

Another thing I learned was to calculate the RPM of the motor, I needed to use the measured hall switch frequency and the number of magnetic poles of the rotor which for the 14 segment rotor is 56 poles and for the newer motor which has 16 segments is 48 poles.
Hope that is of interest to someone.

[whatever]

yes its of interest, one thing I noticed was you can adjust the rpm another way, you know the big plastic thread that locks the magnets onto the original axle? you can wind it out a bit and get higher rpm, as the magnets come off the stator the rpm increases, you probably loose torque but its an interesting effect

[DarylMc]

That sounds reasonable.
Less magnetic influence on the windings from the spinning rotor giving less back emf.
http://en.wikipedia.org/wiki/Counter-electromotive_force