Rear Motor Only (it can be used for front wheel applications with a lot of fiddling around)
Maximum Efficiency = 75% max.
Maximum Torque at 36volts= 50Nm (@17amp@36volt)
Maximum Torque at 48volts =probably same as on 36volts or very close to it.
Maximum Speed 36volt = 23km/hr (in a 24" rim)
Maximum Speed 48volt = 32km/hr (in a 24" rim)
Weight of motor = 6.5kg
Diameter of motor = 18cm
Kit includes motor/controller/spokes/throttle twist type and brake handles with cut off swtches, a 3 speed cluster, torque washers and one torque arm.
Movies of this motor being used :
movie 1 : P3 motor sound with wheel off ground
(in this movie I use a 24v switch first, then a 36v switch, it was taken some time ago when I was running the motor with no speed controller, that way I could draw maximum amps of the motor up hills (max amps being dependent on the winding restistance). Nowadays I use a speed controller all the time, the controllers max. amps can be adjusted inside the controller by adding solder to the buzz bar). The controller that comes with the motor has the maximum amps set to 15-17amps, the motor can handle much higher amps, around 30amps on 36volts, not sure what is max. amps motor can handle without gettting to hot on 48volts).
movie 2 : P3 motor up steep driveway
movie 3 : P3 motor up steep hill
A friend Andrew taking his kids for a spin Nov 2006 in my small trike. P3 motor is a rear motor but I've installed
below in some strong front forks from a bmx bike, I had to spread the forks out quite alot but they are very strong.
Motor has plenty of torque to carry all these people, a very powerful motor due to the planetary gears.
Lucky I built the frame strong is all I can say!
A few pics below of the P3 motor (its a rear motor with a thread on each side), one side for a gear cluster the other side for a brake (band or disc).
(unfortunately most standard bikes wont have enough room to fit a bandbrake or discbrake)
(The middle picture shows the P3 being used as a front motor in my trike (note the rather heavy duty fork section where I had to stop the axle from turning in the dropouts when I was experimenting with starting on 36volts with no controller and a simple on/off switch-not recommended!).
A few pics of the inner planetary gear system with all hardened metal gear sets (the motor does produce some noise having all metal gears but it is not very loud - see video1 above ).
Below is my own drawing of the inner workings of this motor ( a bit rough but you'll get the idea!)
The planetary gears do seem to produce some vibration when new at certain rpm, this settles down overtime. It can be a bit annoying unless you have a comfortable seat but it does go away after running in the motor for a few hundred kilometres.
Below a few pics of the axial flux motor that drives the gear system: There are 8 large neodymium magnets (very strong about 4 times stronger than normal ceramics magnets, neodymium magnets are used in all hub motors that I know of). The second picture shows the axle, brush holder, commutator with windings set in black resin and the 8 neodymium magnets.
{Postscript: the best motors being used in solar cars use axial flux type motors, but they use two sets of magnets on each side of the windings , also they use a halbach array in the magnets and they have many more poles and no gears, they are getting extremely high efficiencies peaking at certain rpm around 98%. The P3 motor and gears peak at just over 70% so the majority of the time the motor will be running somewhere in the 60%-70% range. This does mean this motor will not have as good a range as brushless gearless motors, but it does have very good torque for hill climbing at low speeds}
This motor uses a freewheel mechanism as shown below. Its a very robust design. The motor drives the planetary gears which in turn drive the circular metal plate shown with a red arrow indicating motor spinning direction. The small rollers wedge themselves onto the hardened metal plate but when the motor is not spinning the plate can rotate freely hence the wheel can rotate freely. There is negligible resistance when freewheeling the same as a normal biycycle wheel
For more details on the inner workings of the P3 click here (not finished this part yet)
This motor has one continuous axle which goes through the centre of it (quite unusual for a geared motor), which means that it can handle quite alot of weight. It was designed for the Chinese ebike market which almost entirely uses Lead type Batteries (sealed lead acid absorbed glass mat type). So its designed to take alot of weight, also the chinese tend to use the ebikes alot for carrying two people or for carrying one person and some goods.
Regenerative braking is not possible with this motor due to it having a freewheel mechanism, though if you spin the motor backwards it will act as a generator (the freewheel mechanism engages if motor is spun backwards).
Below is the torque graph for this motor for 36volts:
Graph above is for P3 running on 36volts (if run on 48volts torque will be about the same but top speed increases).
The graph shows no load rpm is 210rpm. Maximum efficiency is 75%, I would have thought a bit lower as its brushed and has quite a few gears in the motor. Though the motor is an axial flux type motor which may increase the efficiency somewhat from a standard brushed motor.
Maximum power out on 36volts and at 17amps (max. amps of the controller) is about 440watts. You can put quite alot of amps through this motor, I've had it running at about 30amps without problems.
The motor is designed to be used on the rear the dimensions are shown below, the large nuts on each side of the motor could reduced in size to make the width needed narrower.
The motor will fit into a standard rear dropout width of 14cm (distance between frame on rear of bike) if you use 1 or 3 speed rear cluster.
If you use a 6 speed rear cluster it will increase the width to 15cm as shown below.
There are some options to fit a 6 speed cluster into a standard bike frame:
1. spread the frame out by a cm or so
2. use smaller width nuts on the motor axle (they are rather thick almost 1cm)
INSTALL INSTRUCTIONS WILL BE PUT HERE SOON (working on it)
A bit more info on this motor:
This motor is built like a tank!!! All gears are hardened steel and I've done my best to damage it (both on purpose and by accident!) without success. The motor is one of the first motors to be designed in around 1999-2000 by one of the pioneering ebike manufacturers in China (now one of the biggest ebike manufacturers in China). There are plenty of the original motors still in use in the Shanghai and surrounding districts of China.
I have no idea how many of these were produced but most likely tens of thousands of them. They did halt production as geared motors in China are being replaced by gearless motors (most of the terrain where ebikes are used in very flat in China) but I"ve managed to find one factory that will produce these motors for me. During a recent visit to China I saw many of these motors still in use. So over the years they have made a few changes in the design ,quite minor changes, but the original design still holds. Some of the changes that have been made are as follows: the freewheel mechanism was changed to all steel initially it had aluminium with hardened steel inserts, they have reduced the number of different rpm motors that come in the motor (from 4 or so down to just 2), a longer lasting glue for holding the magnets in place and some changes in the resin which holds the windings in place (its an axial flux type motor inside (also called a pancake motor), nowhere near as good as the axial flux motors they use in the solar cars but the same basic structure.
This is the first hub motor that I ever bought. I depend on it daily its in my work horse, a trike which I carry shopping, parcels etc in the back. I dont particulary like going too fast and I dont like pedalling much especially up hills, also I like something that is going to be able to take some punishment without damage......perfecto!
Its been quite a long battle for me to supply these motors, firstly I did have alot of problems with some of these motors that were being sent out early on. But it turned out that there were some slack people on the assembly line not doing a good job. So to overcome this problem each motor will be inspected by a man I've trained in China (Shen) to check out the motors thoroughly before being sent out. All the components are really top quality,all the machining is computer controlled so no problems there and the gears will take whatever you can throw at them. The motors wont last forever though, the gear teeth do eventually wear like any geared motor but having been in use for 5 or 6 years in China already I think it says alot for their quality. There is one particular gear that wears down the most and can be replaced if it shows signs of wear.
So I learned the ins and outs of this motor myself having taken many apart and put back to together so I know it extremely well. Also my last visit to China in March of 2006 I spent quite alot of time with the guy in the factory who repairs these motors. He has the technique down pat. He can dismantle one of these motors in a few minutes put in new brushes or whatever is needed and have it back together in another 5 to 10 minutes including some basic adjustments (which are needed when puting in new brushes). Most of his repairs to the motor are for replacing brushes but earlier models the glue that holds the neo-dymium magnets in place would loose its grip after some time and also the resin that holds the windings in place would deteriorate over time and crack, the new motors use a better glue and that shouldn't be a problem anymore.
The motor was designed to run on 36volts, Gary Pelletier one of my customers a technical teacher , tends to fiddle alot and try various things, anyway he checked the ratings of the components in the controller and found that could be used on 48volt no problems (both regulator and mosfets were rated well over 48volts). So he adds another battery gets his top speed up to about 30km/hr and gets some more grunt on hills, and the motor seems to be fine with it, no overheating problems (he's keen to try it on 60volts but I think thats asking a bit much!!!). In my view 36volts is fine,
{postscript: I've changed to 48volts some time ago and I think is much better to have some extra top speed just over 30km/hr}
You can run this motor without a speed controller but really theres no point the speed controllers are designed to allow full speed control so I stick with the speed controllers these days, I did use without a speed controller earlier on and the motor can draw its maximum amps giving alot of power up hills.