How are unwanted motor shaft currents managed in the Leaf?

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KiwiME

Member
Joined
Dec 12, 2021
Messages
15
Location
New Zealand
I can see there's a grounding brush on the reducer intermediate shaft but is there also one on the motor output shaft?

I'd like to hear from those who know and understand how this is done on the Leaf to protect motor and reducer bearings.

Thanks!
 
I'll close this question by reporting that I've found the gearbox grounding brush on the Kona/Niro(classic)Ioniq series. It's on the tail end of the input shaft and appears to ride on the side of the bearing inner race. There is a brush on the motor output shaft as well but it's the circular carbon filament type, not purported to be particularly effective at reducing voltage potential.

These simple splash-lubricated gearboxes, similar in design to the Leaf, have been plagued with noise problems since 2019 and my best determination after following this issue for 6 months is that it's due to poor retention of break-in wear particles leading to bearing damage. There is an internal non-serviceable magnet but evidence indicates that it's not effective, perhaps due to the type (ceramic) and/or location in a turbulent area. Circulating particles turn black after being continually crushed, losing whatever magnetic attraction they once had and taking their toll on rolling-element bearings. Owners find black oil after less than 5,000 km from new! And not just one or two, 100% who have have done an early oil change, so far over 20 owners.

Some of us Kona owners have added aftermarket neodymium magnetic plugs which seem to work much better and they are less subjected to the oil windage being flush inside the threaded boss. I've checked mine and they are doing a great job.

I'd post photos if they were hosted here.
 
Thanks ^^

I'd like to see the photos. If you PM me, I'll send you my private email for you to send me the photos and then I'll post them here. My Google drive hosts the photos so they should have a display life that matches the forum.
 
I'll add the latest news today, a Kona owner found that the OEM internal magnet in the gear reducer is non-magnetic by poking a paperclip into the drain opening. He also photographed it to prove it's there.

Perhaps, it's a cost-cutting move by Hyundai, but I'm accepting that this is the root cause of the dirty gearbox oil problem I've been chasing for six months.

We've had a half dozen oil changes reported in the last few weeks, about 20 in total since last November. Every owner who had a magnetic drain plug installed returned clean oil, those that didn't all returned dirty oil.

I'm happy with those stats and I'm calling this done.
 
Certainly the operating temp of the gearbox housing is no higher than warm to the touch but we don’t know what happens during production.
A few months ago I found a Hyundai part number for an OEM magnetic drain plug that I excitedly posted on relevant forums as being a suitable warranty friendly mod. Several owners ordered one and to my embarrassment reported back that it was identical to the standard plug, no magnet installed.
We have seen in a YouTube video images of one of these internal magnetics covered in particles. The gearbox had failed with inner race damage on one output shaft tapered roller. But this could have been a fluid mechanics phenomenon around the dam formed by the magnet retainer, like a river delta.
The photo of the magnet mentioned above shows almost no particle retention (<3%) despite that the oil was full of particles.
 
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