Help! Shengyi DGW07 MISSING C2 CAPACITOR

[AGS]

View attachment 56782

This photo shows the rubbing on the casing. The wire on the right has rubbed through to the core in one place.

 

[saneagle]

agreed, but it may not have left the factory like that though.
It looks like someone has tried to repair it and didn't do a very good soldering job so he could have cut the sleevings, strings and pulled/creased the wires.
He should at least clean the burn marks.

I looked at other photos of those motors. They have some weird method of soldering the phase wires to each other, like they wound every pole separately, then joined the wires.. The others were neater, but the same solder everywhere.

They're different in that YouTube video above, where they're wound conventionally.

 

[Woosh]

it could be that the OP's motor is much older, before the age of motor coil winding machine.

 

[nepasmecrire]

HALL WIRES WERE IN SHORT CIRCUIT , because of overheating !
I removed the excess solder and re-did the soldering, no more short circuit , now my engine is working perfectly smoothly !!!! It is incredible !!!
I dit it , i fixed my motor !!!!
Thanks to everybody , and yes C2 is useless .
I'll take this opportunity to change the bearings!!! View attachment 2S9A0712bis.jpg

 

[Nealh]

Well doen for finding the short on the Hall connections , being underneath the PCB and only posting the pics a few hours ago , no one could see the oversolder.

In the oriignal pic of the PCB /windings it certainly looks like some heating of the phase wires has occurred but nowcould be down to angle or poor picture contrast .

 

[nepasmecrire]

A year later, here I am again, my engine is still working but badly, very badly! The engine is slipping, it's not mechanical, it's electronic slipping. I can ride in assistance 4 on flat ground (20km/h). I can put it in 5th gear to reach 25km/h (only on flat ground).The slightest hill or headwind makes the engine slip, it's horrible, the engine makes a disgusting noise. Impossible to use the trigger in any circonstance without slipping.
I'm tired of disassembling and reassembling this shitty engine of this shitty bike every time. I'm going to change the wheel with a 500W geared motor which should be much stronger. My controller, which is not the original one (a big mess), is 17A, which is enough for a 36V 500W motor .(note that my crappy battery on my crappy bike is, contrary to what is written on the bike and on the MOMA website, a 12S and not a 13s!)
DON'T BUY THIS BIKE ! DON'T BUY MOMA ! AVOID IT !

 

[nepasmecrire]

I bought for riding montains and hills a SPECIALIZED TURBO LEVO ALLOY . With a 90nm motor , it is night and day ! The bike climbs everything ! Awesome ! But believe me or not, the motor which has a belt, is so smooth that it is sanitized of acceleration sensation, unlike my crappy MOMA which has, or rather had punch. nevertheless I absolutely do not regret the purchase of my turbo levo which with a much smaller and under-volted battery, goes twice as far and climbs to the sky without ever making the rear wheel spin.