Magic PIe 4 sometimes does not start

[Woodward]

I have a Greenspeed Magnum with a Magic Pie 4 fitted and a 48V 30AH GM battery, its currently done nearly 6000 kilometres with no issue.
I have been getting something around 4.5 kilometres per Amp hour in quite undulating terrain. I live in a rural area, a normal trip on the trike will be either 20 kilometres (twice a week) or 60 to 80 kilometres (every fortnight or so)

Its started to have a problem, occasionally when one opens the throttle after one has come to a complete stop, it will not start, if one moves the trike  a bit  (say around half a metre) either forwards or backwards, it will be OK. A Cycle Analyst is fitted, it is working OK, ie does not switch off in the fault condition.

Lindsay

[Bikemad]

Hi Lindsay andto the forum.

I'm not quite sure what the cause of your problem is, but it is strange that the partial rotation of the motor is enough to start it working again. The only thing I can think of might be a failed or intermittent Hall sensor in the motor.

I know that the MP4 won't start if all three of the Hall sensors are disconnected, but I don't know what happens if just one sensor is not working correctly.

Unfortunately, to check the operation of the hall sensors, it will be necessary to remove the wheel so that the controller can be taken off to access the Hall sensor wires plugged into the rear of it. But as the fault is only intermittent, it may be very difficult to locate.

When/if it happens again, try moving the trike forward just an inch, to see if the motor tries to turn. If it does try to turn, move the trike back an inch to the same position it was in when it refused to run, and see if you can recreate the fault.

If it is related to the rotational position of the motor, then it will probably be a Hall sensor fault. 

Alan
 

[Woodward]

Many thanks for your reply. moving forward a small amount does not have any effect. although I will try this test again next time it happens. An open phase winding can cause this (although one only has to move an inch for the motor to start) but it generally runs rough if this is the fault and its as smooth as silk. I actually have an Magic PIe 5 controler on the way and I will change this to see if it effects the fault. Note: I need to move the trike more than  just a little, ie around half a metre and the trike does NOT have to be moving for the motor to start, ie the fault can be cleared by just movung forward of backwards half a metre and then the the throttle will work. Probably be a good idea to test the hall sensors though.

A question can one fit an external controller, by bring out the hall efffect leads and phase winding leads of of the motor unit I have a pair of Golden Motor extenal contorers for another job.

Liindsay

[Bikemad]

I have just had another thought.

Check that the wiring is properly secured to the axle where it comes out of the controller. If the wire clip has come loose, it could allow the cable to rub against the centre of the brake disc, which could possibly short the +5V, throttle signal or brake signal wires to ground, preventing the motor from running.

This would also be affected by turning the wheel as you've described previously.

Alan