CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

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rockstar195   100 W

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CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by rockstar195 » Jul 07 2019 7:25am

Here is the situation: The hub motor wiring harness is kissing the brake disc fasteners and needs improvision to minimize contact. This is a QS V3 5kw motor from www.em3ev.com. I emailed them and they said: " If you using some zip ties can help or some tape if the fabric is bulging or has any frayed edges." I might grind down the heads of the fasteners, drill countersink holes into the brake disc so that the fasteners are recessed further away from the wiring harness, OR might orientate the wiring harness towards the rear and grind the dropout (which I'm trying to avoid) for the harness to have a little bit more room.

Image

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dogman dan   100 GW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by dogman dan » Jul 07 2019 7:51am

Looks to me like they machined the axle wrong. really cant see much in that pic though. It should not be exiting so close to the rotor. If machined too deep, fill with epoxy. Cut more if the wire needs a longer notch on the outside.


That wire should be coming out right inside the notch on the dropout. Not sure why it points the way it does, can't see which way your dropout points.

Jonno   10 W

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by Jonno » Jul 07 2019 10:38am

Have you positioned the wheel in the middle of the swing arm?
I found that I needed 3 U shaped spacers/washers inserted between the arm and the cable otherwise you will have trouble with your caliper.
This will also allow more clearance for the cable.
Also exit your cable to the rear and bring it back around the end of the swing arm.

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wturber   10 MW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by wturber » Jul 07 2019 1:15pm

Grinding down the heads of the fasteners or countersinking the holes on the rotors seems like a recipe for disaster. Especially on an ebike that is going to be operated at high speeds.

I like dogman dan's idea of filling the hole with epoxy. You might even used some fabric or fiber fill to add some "body" to the epoxy
fill/plug to help it maintain shape while the epoxy cures. Choose a high grade epoxy that can withstand higher temps while you are at it. You can tuck some wax paper and then some filler cardboard or paperbetween the wires and the epoxy to help avoid having the epoxy stick to the wires.

Once you have bought some extra space by using the epoxy, I wonder if wrapping the wires at the exit with adhesive aluminum foil might also help reflect heat and protect them a bit?
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ScooterMan101   1 MW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by ScooterMan101 » Jul 07 2019 1:31pm

From What it looks like in the picture it has a white protective cover over the wires , and under that it looks like they have a wire that spirals around the main wires ,

It looks like they are the only two parts that touch the rotor bolts , not the main wires.

Cut back an inch or so of that white cover , and cut off the same amount of that wire that spirals around the main wires .
then
Zip Tie that short 1 inch or so section to the frame/dropout section.

as well as epoxy to get the wires to move outward 2-3 mm .
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fechter   100 GW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by fechter » Jul 07 2019 2:12pm

I'd see if there is a way to put a zip tie around the wire to hold it away from the rotor bolts.
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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by LeftieBiker » Jul 07 2019 2:15pm

Shrink tube over the white protective cover should pull/squeeze it out of the way when heated.

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by Drunkskunk » Jul 07 2019 3:56pm

This is one of the reasons I prefer the Clyte and Cromotor over the Q motors. the wires Exit on those 90° to your wires, meaning you can rout them under the nut through the slot in the dropout, avoiding exactly your current problem.

For your motor, you might try putting a hand bend in each of the power wires, so that they come out parallel to the axle, then take a sharp 90° bend to follow the frame, instead of the curve that they are in now. You'll have to space them, one high, one middle, one low, with the hall wires where ever they will fit. then put a ziptie around the axle and the parallel part of the wire.
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Choppa66   10 W

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by Choppa66 » Jul 07 2019 7:26pm

Hi.
Had the same problem with the maxus 5k motor on my frame. I also had to space out the rotor by 2 or 3mm to from the motor so that the caliper doesn't rub on motor when centered on disk. Might be worth checking that before you do anything with the wire. I also countersunk the rotor screw holes and replaced the button head Allen screws with stainless countersunk Allen screws,if done properly this shouldn't cause any issues as a countersunk bolt has a better shear strength than one that isn't as you are increasing the surface contact area of the bolt. The wires for these motors are a real pain in the ass!! Can try and post some pictures if you need them? :thumb:

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by e-beach » Jul 07 2019 9:57pm

Tie wraps? Tape? How is that going to keep the wires away from the rotor screws? Both ware out over time. Something like a hose clamp would only cut the wires over time. I would request to EM3 that they send you a new motor with an axle that has adequate space between the exit point of the wires and the disk screws. If they want their old motor back, tell them they should send a pre-paid postage label so return shipping doesn't cost you.
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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by john61ct » Jul 08 2019 5:30pm

yah rots of ruck

not saying it will work here, but if a "perfect hose clamp" would work, maybe adding a stress relief layer

Check out the Clamptite tools.


rockstar195   100 W

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by rockstar195 » Jul 10 2019 10:08am

So far zip tie around axle and tape is helping and ordered some stainless steel flat countersunk allen screws.

CHOPPA66, please post some pics.

Choppa66   10 W

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by Choppa66 » Jul 10 2019 6:05pm

Still cant work out how to post pictures!!? Not the sharpest knife in the draw when it comes to computers!! If you want I can always email you some if you want to PM me you email address? :thumb:

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by LeftieBiker » Jul 10 2019 8:35pm

Choppa66 wrote:
Jul 10 2019 6:05pm
Still cant work out how to post pictures!!? Not the sharpest knife in the draw when it comes to computers!! If you want I can always email you some if you want to PM me you email address? :thumb:

Upload the pictures to a free image hosting service like IMGUR (NOT Photobucket) and then copy the url for each photo and post that here. If you use the INSERT IMAGE option in the editing tools, the image should show up here.

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e-beach   1 GW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by e-beach » Jul 10 2019 8:58pm

Choppa66 wrote:
Jul 10 2019 6:05pm
Still cant work out how to post pictures!!? Not the sharpest knife in the draw when it comes to computers!! If you want I can always email you some if you want to PM me you email address? :thumb:
The file size of the pictures has to be under 512k or they won't post on ES. Download GIMP (it is a free picture editor) Drag and drop the picture into GIMP, Go to Image, scale image, change the size to 640 x any other size, scale image.

Now your image is small enough to post on ES.

:D :bolt:
Favorite Quotes:
"This is L.A., sugar. There is no 'over the top." Chris Erskine
"At a certain point the entropy wins." Maria Helena Braga

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Liahona, Yescomusa 36v 800w generic front DD.
1992 Trek 800, Yescomusa 800w 36v front DD.

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by John in CR » Jul 11 2019 12:52am

I can't tell much from your picture except that it appears that your axle is entering the dropout 180° from the direction it should. The wiring harness should exit the axle down or rearward so you can create a drip loop that will prevent water from running down your cable bundle like a river channel directly into your motor. Given enough time and rain conditions, no matter how well it looks to be sealed with silicone, the motor will fill with some water. When cold rain hits it during/after use, the air inside will cool and contract resulting in low pressure and suck water running down the cable directly into the motor. If you have the axle wrong that will put a properly assembled motor with the hall sensors at the lowest point, and the water will reek havoc. A drip loop makes the water have to flow uphill and forward to get into your motor, so it stays dry, unless it's sealed so well that it get sucked in inside the cables themselves (see Justins presentation and testing in that regard).

It also looks like you have some spacer(s) pushing your brake disc out further than it should be.

I wouldn't grind the heads of your bolts, because they can get stuck in there pretty good. Buy some new ones with a lower head profile instead.

As other have stated, zip ties or heat shrink get help squeeze that fiberglass sleeve out of the way.

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wturber   10 MW

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Re: CHIME IN: NEED SUGGESTIONS TO AVOID MELTDOWN!!!

Post by wturber » Jul 11 2019 1:38am

e-beach wrote:
Jul 10 2019 8:58pm

The file size of the pictures has to be under 512k or they won't post on ES. Download GIMP (it is a free picture editor) Drag and drop the picture into GIMP, Go to Image, scale image, change the size to 640 x any other size, scale image.

Now your image is small enough to post on ES.

:D :bolt:
Yes. The filesize is what is important. You can pretty much always use a size of 1000 x 1000-ish. Just dial down the JPEG quality factor to make sure the size is small enough. More pixels and more compression generally works out better. Posting to external links makes the posting less valuable in the future because the outside links tend to disappear over time.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
viewtopic.php?f=2&t=90369

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