KiwiME
Posts: 9
Joined: Sun Dec 12, 2021 8:48 pm
Delivery Date: 13 Dec 2021

How are unwanted motor shaft currents managed in the Leaf?

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!
KiwiME
Posts: 9
Joined: Sun Dec 12, 2021 8:48 pm
Delivery Date: 13 Dec 2021

Re: How are unwanted motor shaft currents managed in the Leaf?

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.
SageBrush
Posts: 7301
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: How are unwanted motor shaft currents managed in the Leaf?

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.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. Cal
Two years in Colorado, now in NM
03/18: 58 Ahr @28k miles. 10/21: 53.4 Ahr @ 40k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018. Sold 11/2021, awaiting Tesla Model Y
KiwiME
Posts: 9
Joined: Sun Dec 12, 2021 8:48 pm
Delivery Date: 13 Dec 2021

Re: How are unwanted motor shaft currents managed in the Leaf?

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.
goldbrick
Posts: 1726
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: How are unwanted motor shaft currents managed in the Leaf?

the OEM internal magnet in the gear reducer is non-magnetic
Very odd indeed. I wonder if they just used the wrong kind of material and its Curie temperature was exceeded.
KiwiME
Posts: 9
Joined: Sun Dec 12, 2021 8:48 pm
Delivery Date: 13 Dec 2021

Re: How are unwanted motor shaft currents managed in the Leaf?

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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