Magic Pie, Brushless motor or not?

[Andrew]

Hi,

i was under the impression that the MP was a brushless motor like the HBS motors,  is this not the case?

Is this why the Mp is much louder than HBS motor?

[Magzy]

The MP is a brushless motor. The noise mine makes is a huge disappointment over what I was expecting.
It makes a clicking/pinging poise that comparable in DB to one of those idling 4 stroke engines you see on some push bikes.

I think mine is defective however.
http://www.youtube.com/watch?v=uRErVvVD4E4

No one can give you straight answer on how loud the HBS is in comparison to the MP because it's all relative to the listener.
If my MP is the standard to be expected and the noise bothers you then DO NOT BUY a MAGIC PIE. Golden motor have yet to come back and confirm this is the case but Bikemad seems to think that the noise is normal and this worries me because If he's right and other people confirm that the my MP is normal then I've wasted a huge chunk of cash and will never seem my money again.

the only way to compare the noise is to buy a cheap one like this which is made in the same factory as the GM HBS it's practically the same (for $167 delivered which is $10 cheaper than the GM equivalent AT $177 delivered and they will answer emails on issues unlike the criminally poor customer service from GM)

same or different?



It will connect to the GM wirings with ease but you will need to reconfigure the controller which is easily done by reading the install manual for the external controller I'm thinking of getting this just because it will be quieter.

There's a host of others on ebay that will do them for even less.

[Bikemad]

Is this why the Mp is much louder than HBS motor?

Andrew, I think there are several factors that may cause the Magic Pie motor noise to be louder than the HBS motors.
The Magic Pie is a much larger motor with 56 magnets instead of the HBS's 46. Theses addition magnets help to produce more power, and because they are housed in a larger diameter hub, they are positioned further from the axle centre, exerting a greater torsional force (torque) on the stator assembly.

The smaller stator on the HBS motor uses a pressed steel plate to form the main centre part of the stator, which is very rigid and less likely to flex when motor torque is applied to it.


The Magic Pie has a much larger diameter stator which consists of an eight spoked cast aluminium centre assembly, and I suspect these spokes are flexing very slightly when torque is applied.


With each magnetic pulse, the stator will flex very slightly under load, but will instantly spring (ping) back to its normal position when the pulse stops, and this it what I think is causing the "pinging" noise. The hub cover seems to act a bit like a loudspeaker cone and amplifies these sounds,  making them far more obvious, which is why the freewheel bearing and ratchet noises are more noticeable on the hubmotor than it would have been on the original wheel.  I suspect the larger hub cover on the Magic Pies also produces a louder noise output than the smaller HBS hub, a bit like different sized loudspeakers.

Please note that this is just my opinion, and I could be wrong.

Alan
 

[Andrew]

I'm still yet to fire up my PIE as i'm waiting on a pair of bespoke locking washers that will fit under the rear drop out on my mountain bike due to it having very shallow drop outs, and before you ask, I have orderd a torque arm too.

Magzy,  I have followed and commented on your on going thread/problem and it has become an increasing worry as I stand in a similar situation as you and have had to deal with a manufacturing fault of my own when I received my kit from China.

MEB,  the statements that you have given on Magzy's thread and on this thread are eye opening and do help complete some missing links to questions/answers i've had about GM and Chinese business. I can completely believe that the idea of quality control be done by the consumer himself which would be more econical to GM than having it at the factory.  I can also see how down graded goods could be given out to a minority which are at 'arms length'.  - However I hope this isn't the case...., but most probably is.

Alan,

A light amongst darkness on the forum,   I must admit I am already considering alternatives to the PIE and I have not even ridden it yet.  I really hope to have my bike up and running very soon. I will keep it at very safe parameters to begin, and will hopefully be able to report back positive first hand experiences.
there are quality issues I have found other than the tear in the Rim, but oneds I can over look if the bike/motor delivers.

Thanks for all the feed back and support

Andrew

[Leslie]

The Pie makes a cliicky whir noise.  

Both mine are the same.  Even to spin they whir.

It is very efficient and I can have this MP use 55 watts for a 6 km trip.  An MP recumbent low rider here, whir and clicky as it is, does aprox 7wh/km.

The MP noise indicates nothing bad, infact both my HBS hubs used to gruble quite loudly during take off's and "hum"ble along up hills.  Not what I call silent but quieter than the MP


If anything goes wrong Andrew you will be looked after OK .

[Andrew]

If anything goes wrong Andrew you will be looked after OK .

i take comfort in the above statement. Thanks mate      it's nice to be surrounded by others who know what they're doing