GL-2 Hub Motor Kit
$450aud and $120aud freight
Peak output power on 48volts approx 620watts
Has Higher Torque Characteristics than GL-1 or 408 style motors
36volt 18amp in 26" rim = 40km/hr approx.
36v 18amp in 26" rim = 30km/hr approx.
Pic below shows gl2 in 24" rim
Below: newer style gl2 showing strengthening ribs on side plate
GL2 is a gearless brushless motor
I use one of these motors on a daily basis for running into town ( about 10km
round trip) its proven to be extremely reliable, I have never opened the motor
in a number of years of use, the controller I'm using has also been very
reliable ( controller now supplied with motor is a newer infineon chip one).
The GL-2 I was fortunate to have the opportunity to test on a whizz bang
very expensive testing machine at an ebike factory in China way back in late March '06
( before the motors had come on the chinese market)
At the time I was staying at a large ebike factory ( Luyuan in Jinhua City), in
the office there was a new motor sitting in a corner which the company had
recently recieved from a supplier which they were going to test. I suggested I
would be interested in seeing how its tested and the results, at the time this
style of motor was not in use in china, today its in common use in china, it
took probably 15 months or so from the time it was a new style motor till it was
widely used in china ( a very short period indeed). Today its probably the most
common style of motor used in electric mopeds in china since it has higher
torque than the previous style of motor ( gl1 style). The original style of
motor used in china was the P3 motor which was developed approx. 1989 ( its
still widely used in china also).
Gl2 motor below diameter 22cm weight = 6.5kg:
( note picture below is older style gl2 without ribs )
The motor can run on 36v or 48volts ( I haven't tried on higher voltages but
I suspect it would be a very good motor on up to about 72volts and 20amps) the controllers
used with this motor are usually set for around 18 to 20amps though the motor is
quite happy with up to about 30amps.
I first received some of these motors (12th of June 06), over the years some
minor changes have been made, the main one being some reinforcing ribs on the
side plates near where the thread for cluster is located, being quite a
large diameter motor there were some instances of cracking of the sideplates,
hence adding the strengthening ribs in that area.
In terms of torque the Gl2 is above the 408 cystalyte and Gl-1 motor.
Top speeds are approx the same as gl1 and 408 motor. At the moment this type
style of motor is the highest torque brushless gearless style motor that i'm
aware of ( there are some even larger diameter versions of this motor out now
but I have not tested or seen data on the torque they produce, they are even
narrower at the outer edge than this motor).
Kit comes with infineon chip controller with regen braking ( controller is also programmable eg. low voltage cut off and max amps)
The controller used is the infineon chip 6 mosfet type controller. It has
regenerative braking. Some parameters such as maximum amps and low voltage cut
off can be adjusted via computer using a usb-ttl cable and the program ( see
infineon controller page)
The motor can be run on 36volt or 48volts
Throttle supplied with kit:
thumb or twist type ( can come with leds for battery voltage
monitoring depends on customer choice). Choice of throttles shown below.
Kit comes with brake handles ( with cut off switches which can either be used for regen braking or for cutting off controller power when brakes are applied just as a safety feature)
. The motor comes spoked into a dual wall wide aluminium rim. A cluster will be supplied ( 6 or 7 speed) . Motor will come spoked into a rim, hence the freight costs are a bit high. The reason why I prefer to send spoked into a rim, is that the motor is quite narrow. This means that unless you use with a quite strong rim there is some chance the rim will move ( bend ) slightly under stress and can lead to spoke breakages. If you prefer the motor not in a rim to reduce costs I can send that way, but you will need a quite strong rim to mount the motor into ( I thin rim ( eg a road bike rim) less than 2.3cm wide is not suitable). The spokes I use are thicker than normal spokes approx 2.3mm diameter. You can see below why a wide rim is required, the gl2 motor is quite thin where the spokes join to the motor compared to say a gl1 motor. A thin rim will flex sideways and eventually lead to spoke breakages ( known from experience).
Picture composite below shows some motors after spoking ( pic quality not so good sorry), note left hand bottom pic shows the motors/rims in back of my electric trike in china, just shows some of what is needed on the practical side to put together the kits. Motors/rims/spokes are all sourced from different suppliers, they are then taken to a spoking shop where they are laced into the rims. For more info on rims used see rim section ( link insert later)
The motor is extremely quite almost completely silent, most brushless hub
motors have a noise associated with the electronics but it is almost inaudible.
Inside the motor:
There are 4 parts to the motor and no moving parts excepting the bearings.
Benefits being no maintanence (unless a hall sensor fails or water gets inside
the hub)
Face plates are made from an alloy to keep the weight down. Bearings would be
easily replaceable if ever needed.
Both face plates are identical with identical threads. One thread is used for
the gear cluster (a 3 speed cluster is supplied on the motor)
the other side is for a drum or disc type brake. A rubber seal keep stops water
getting into the motor via the axle.
Bearings seem to be good quality. Can be removed by hitting the face plate very
firmly on the ground a few times (the chinese method!( no puller required).
Since the bearings are placed well inside the face plates it means its possible
to remove the threads and get a very narrow motor which can be used as a front
motor application. Minimum width motor will fit is 8cm if threads are removed.
But very strong front forks would be required to avoid any fatigue of front
forks from the torque of the motor.
The axle flat stops just before the motor thread (on face plates), if the motor
was to be used as a front motor the flat on the axle would have to be extended
(can be done with a hacksaw and a grinder and a bit of skill.....see gl-1 page
for instructions)
The windings of the motor are somewhat different to the older style non-geared
brushless motors. They are very similar to the fisher-paykel washing machine
motor structure ( which I did quite alot of testing on some years ago to use on
a trike, with some success). It means the motor has alot of poles and quite a
large diameter but is quite narrow.
What would a chinese motor be without some bamboo!!! Inbetween the iron cores they put strips of bamboo which wedge the
windings in place so they cant move. This is a common practice and very few hub
motors from china will use plastic instead of bamboo, I think its sort of nice
to see something organic being used in these motors.
The iron core focuses the magnetic field as is the case in most electric motors.
Hall sensors are located as shown.
Hall sensors shown below. They are glued in position as with all the brushless
hub motors I've come across. Picture below right shows the 3 main power wires
(its a 3 phase motor thanks again mr tesla), the three main wires which come out
of the motor divide into a number of copper wires (5 or 6 sorry cant remember
exactly), which then are wound around the iron core. All motor winding is done
by hand as the preferred method for making motors in china.
There are 46 neodymium magnets glued to the iron rotor (the iron helps focus the
magnetic field).
below is a pic of the new side plates with strengthening ribs.
Below a picture showing difference is size of gl1 style to gl2 style motors.
The motors have changed slightly over time, the torque has increase a little bit more over time ( not sure how they have achieved this maybe the magnets have increased strength), but below is a recent torque graph of a gl2 motor, max torque at 48v 18amp is 55Nm stall torque. Graph from early 2009.
Here is an older torque graph from back in 2006 where max torque was a bit lower.(it may even be due to using a different controller in the test)
The following results were obtained.
Unloaded:
0.912amp
(@321rpm)
Maximum Torque: 48.42Nm
(@ 18.87amp)
Maximum Efficiency: 84.89%
(@281rpm@12.38Nm@8.942amp@364.3watt)
Maximum Power Out: 641.8watts
(@74.86%eff@214rpm@28.64Nm@17.8amp)
Rated Power:
350watts
(I have no idea how rated power is calculated by the machine )
Future experiments with GL-2 motor: As there is alot known about fisher
paykel style windings mainly due to them being used in home made wind
generators, and also more recently being used as motors in ebikes/small evs.It
would be possible for the hard core tinkerers to change how the windings are
connected ( not rewind the motor just change connections between the coils), I
haven't tried this with the gl2 but I have done it with fisherpaykel motors
which are almost identical structure. It would be possible to do the following:
1. Changing how the coils are connected to each other: series
connection for hgiher voltage use, parallel for lower voltage use with higher
torque ( it would also change the rpm of the motor). May allow the motor to be
used on very high voltages
2. Change windings from wye to delta via switch: delta connection will
give higher rpm and allow higher amp use ( higher torque). Most hub motors are
in star
type connection changing to delta increases top speed by 1.7, but decreases
torque by 1.7 so more amps are needed to maintain torque.
3. combination of both the above would allow to change
characteristics of the motor: rpm, max voltage it could run on and max amps it
could run.
There would be a very large number of different combinations could be
tried..............theres a project for an engineering student!!!
First would be needed to identify how the coils are connected as the motor
comes from the factory , wye connection is used, but I haven't checked how many
coils are in parallel/series as yet, so not sure what combinations will be
possible, but its certain that the characteristics of the motor could be changed
considerably.
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