Whistling whine from Golden motor front hub (damaged controller?)

[Joaqthru]

I was given a Golden Motor Magic Pie front wheel and hooked it up to a bike and batterylink to Short video of whine/whistle sound

It's possibly a Gen 2 or up to a Gen 4. It's been hard to find enough info to determine and the company has been unresponsive. It has an internal controller.

I was unable to find a matching 8pin connector available so I got a universal throttle (male juliet) from ebay and a (female juliet) to bare 3 wire (black, white, red). I tested the continuity between the 3 pins and wires and compared it to the diagram presented on ebay for the +, -, and 5V pins.

I cut the 8pin off the controller end and tested DC voltage on the controller wires with a multimeter and found 2 combos gave ~50V, one gave ~55V, and the others gave very small amounts. I assumed the combination that gave me 55V was the +/- in correct order that the multimeter was reading positive voltage and not negative.

I then tied the +'s together, -'s together and tried the white 5V throttle wire against each controller wire. None of these allowed the throttle to work. I then tried it with the + wire going to each of the 50V wires instead of the 55V. Still the throttle did not do anything. Then I accidently jumped what I thought were the positive and negative (read 55V) and the motor spun. I was hopeful at this point but got a little jump happy and decided to just try some combinations. I found that one of the 50V wires jumped to the "negative" also made the wheel spin, but then the motor made a whistling/whine sound. And now jumping does not spin the motor. Now when I turn the battery on, the controller whines/whistles.

What have I damaged? What will fix it? A new controller? Replace a piece on the current controller? I am also contemplating a new cheap rear motor that is ready to accept a standard 3 pin throttle if the fix seems too time consuming or expensive as a front hub motor doesn't seem ideal for my uses, but will try fixing it if its cheap!

Also, what did I miss as the proper way to use a multimeter to test which wire goes where from the throttle without getting jump happy and breaking things? I feel like I was close to being able to tell which wire went where but am lacking some information.

Thank you for any and all advice fellow tinkerers!

 

[amberwolf]

Not knowing what the wires you've connected together during the experiments connect to inside the controller, there's no way to say what might be damaged in there with any certainty, or whether its' fixable, but it is very likely that something is damaged.

The simplest way to fix it is to remove the internal controller, and run a cable out from the motor phases and halls to an external controller (or use a sensorless external controller that doesn't need the halls, just the three thick phase wires).


There's not really any certain way (especially with just a voltmeter/multimeter) to tell which wires do what, on any particular controller / system, without markings, diagrams, etc.

You would need to trace out where they go inside the controller, (or whatever part(s) you have to figure out), and see where they end up on the board inside. It's possible some things will have markings on those pads that will make it obvious what they are, mostly they won't. Sometimes you can match the markings to other systems that people have posted about here or elsewhere, mostly they won't match. You can sometimes trace the pads to specific parts on the board that do certain things, to find out what they are for.

If there are connectors on a system, and it's a brand name and/or has model numbers, then you can often find diagrams for which pins are which.

For instance, an image search for
golden motor magic pie connectors

golden motor magic pie connectors - Google Search

finds many relevant-seeming results. The third hit

Looking for Magic Pie wiring diagram

Looking for Magic Pie wiring diagram

goldenmotor.com

has several connector pinouts (two copied below); i don't know if any of it applies to your specific system or not.

 

[TommyCat]

Hi Joaqthru,
I'm a Magic Pie V5 rider...

You are working on a Version 2 for sure.
You may be able to get a used controller for it if lucky. Or that motor may be a good candidate for an external mounted replacement, but with a fair amount of work.

To help with the damage assessment I'm thinking that the V5 and V2 MAY use the same PCB wiring termination labeling.
I think the wire coloring is similar. See if this helps.

But my best advice is to get you to go over to the Golden Motor forum. Where 'Bikemad' is an expert in all things "PIE".

Magic Pie & Smart Pie Discussions

I'm sure there are some examples of internal to external controller conversion mods there, as well as spot on advice and support.


Regards,
T.C.

 

[Joaqthru]

Thank you amberwolf.

I did find a few wiring diagrams that looked promising. One idea looks like I should have traced the connector pins to the wire colors with a diagram before I cut it off. Another is I should have posted here and figured out it was a V2 first! It's good to know that it's not straightforward to figure out what is what without a diagram or manual.

And thank you TommyCat

For shedding light on which version this Pie is. And I believe that the Golden Motor forum is where I was seeing the most info and diagrams about this, so I'll go dig some more about external controllers for the V2.

I'll weigh the external controller vs a different rear motor.

Thanks guys!