Crystalyte Dual Speed or Dual Torque Motor: Windings 408 and 4012 in one motor

  rear motors only available

$650aud and $120aud for freight = $790aud

As crystalyte motors do not have any gears inside them the speed the motor turns is exactly the same speed (rpm) that the outside of the wheel turns. So the top speed you can achieve depends on what size rim you put on the motor, conversely the amount of torque you have also depends on the size of the rim you use (the smaller the rim the lower the top speed and higher the torque).

A novel way to get around this problem, is to have one motor which has two separate sets of windings in the one motor. One set of windings can be used for high top speed and the other when more torque is required. To select which winding to use either a relay or a switch can be used and it means a gearless motor can
be quite useful on steep hills when the slow speed/high torque winding is selected..

The crystalyte dual speed (or dual function) motor has two sets of windings. One is the same as the 408 motor windings the other the same as the 4012 crystalyte motor, both sets of windings are inside the one motor. The motor uses only one controller which can power either of the two windings.

Top Speed in 408 mode is almost the same as a  408 motor alone (you do loose a slight amount of top speed about 10%) so around 37km/hr in a 26" rim running on 48volts. When the 4012 winding is selected the top speed on 48v in a 26" rim drops way down to about 18km/hr but the torque available increases. So you can use a gearless motor for hill climbing and for running efficiently at low rpm.
Below shows a dual speed motor being wound, picture at right illustrating that the stator needs wider than normal slots to accomodate the two sets of windings.

The Dual Speed Motor looks exactly the same as the 408 motor except there are two sets of wires come out of the motor. The size is identical weight slightly heavier just over 8kg.

Below shows how a relay or switch is used to change windings, only one controller is needed.

Below shows the relay used to select windings the relay itself can run on 36v or 48v and uses very little current to operate.

 


Had a couple of independent torque graphs made of this motor, results below. Windings used are 408/4012 combination.

Heres some more practical test data on how the dual speed motor performs in an ebike ( testing date: 12th June, 2007) :
dual speed results  or  dual speed raw data
 

Whats in the kit:

1. dual speed motor spoked into a strong/wide dual wall aluminium rim 3.2cm wide (spokes are thicker than normal bike spokes: 2.3mm to 2.6mm dia)
2. controller : can run on 36volts or 48volts maximum amps is 20amps ( digital controller using infineon chip)
3. relay for switching windings ( you will need to connect up the relay to the motor/controller)
4. throttle: thumb type or twist type
5. torque arms/torque washers
6. 6 speed cluster on the motor
7. left and right brake handles with cut off switches

Important Note: switching between windings can only be done when throttle is in off position, otherwise there is risk of damaging the controller especially if
the motor is under load when switching between windings . There is no need to stop the bike, just to momentarily throttle off then switch windings, then throttle back on, it can be done easily without the bike loosing any momentum, a bit like changing gears in a car.
 

Installation:  

Installation is quite straight forward, there are a few things to note:
1. the spokes will be quite loose when you get the kit. Please adjust them to your desired tension before riding. 
2. ensure that you use the torque arms supplied with the kit, these stop the axle turning in the frame.

Note: when you recieve the motor kit, the spokes will be quite loose, please adjust to the tension you require and if necessary you can dish the spokes to centre the rim (dishing means pulling the rim slightly to one side using the tension in the spokes). Spokes MUST be tightened before riding your bike.

I will put up some more detailed installation instructions on here as time permits. 

Other Notes

1. the motor can be run on higher voltages up to 72volt, but a different controller is necessary to run over 48volts.
2. other windings combinations can be supplied apart from 408/4012 but I need to order from crystalyte company.
3. there is no provision for disc brake on the motors, but a different side plate can be supplied if a thread for disc brake is required on the motor,
it will make the motor slightly wider than a standard 13.5cm rear width though.
4. motors can be supplied not laced into a rim if you want to reduce freight costs
5. 20" and 26" rims are commonly used sizes so I have motors laced into those, but can lace into other size rims if needed.
6. stainless steel spokes cannot be used with hub motors as they get brittle and break very quickly

Postscript: its also possible to change a single winding hub motor into a dual speed hub motor. Normally hub motor windings are in star type connection.
Some ebikers have experimented with having relays inside a motor so that the windings can be switched from star to delta on the fly, when switched to delta type connected winding connection you get a higher top speed but the amp draw also increases significantly. Quite a job to do this requiring finding the star connection point and then wiring it to relays placed inside the motor........a big big job.

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Copyright 1998-2009 by Brett White on all images/text/information and graphical materials on this website.

(2 top most images above from cryrstalyte website)