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MSX 84V mosfet blown. Options?


mrelwood

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2 hours ago, Marty Backe said:

my question to @mrelwood (pictures, etc.) is more about the quality of the wiring and connections to the hall sensors.

I replaced the wires at the same time with the main motor wires a few days ago already, but only took these photos for the cable order. I’d consider the build to be fine, I didn’t spot any obvious points of potential failure. Except that the wires run in the same rubber housing with the grill heating elements... sorry, I mean main motor wires!

B4-F2-D367-1150-495-B-998-C-C924-C0-B002

792-FBA84-9693-46-A3-86-C7-5688798208-FE

Edited by mrelwood
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9 hours ago, mrelwood said:

I replaced the wires at the same time with the main motor wires a few days ago already, but only took these photos for the cable order. I’d consider the build to be fine, I didn’t spot any obvious points of potential failure. Except that the wires run in the same rubber housing with the grill heating elements... sorry, I mean main motor wires!

 

792-FBA84-9693-46-A3-86-C7-5688798208-FE

Nice pictures - thanks :thumbup:

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Mrelwood dont remove rotor only pull it downt to have access to hall in my post photo 8.

Yesterday i assembley V5F+ and it works hall sensors works fine.

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The magnets are strong enough to pull the rotor back in. But I was eventually able to separate them, and got a good access to the sensors, and got them removed. The text is partially covered by glue, but I’m not worried since these seem to be functionally universal parts, and I even have some available locally. Future is showing some light at the end of the tunnel once again!

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26 minutes ago, mrelwood said:

The magnets are strong enough to pull the rotor back in. But I was eventually able to separate them, and got a good access to the sensors, and got them removed. The text is partially covered by glue, but I’m not worried since these seem to be functionally universal parts, and I even have some available locally. Future is showing some light at the end of the tunnel once again!

Very impressed with your dogged pursuit of rebuilding the wheel :cheers:

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Dont separate just pull down, i separate rotor in bwheel u8 motor it can be done only with hands but when i try to pull all together rotor jumped in right position and almost didnt cut my fingers i wouldnt do that again, and it was only 350W motor. If you still want to separete rotor from magnet be careful, seriously.

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@mrelwood: you earlier asked about high-temperature wires, at least TME carries some fiberglass-cables rated for +350C to 400C from Lapp Kabel and Helukabel:

https://www.tme.eu/fi/en/katalog/heat-resistant-cables_100565/?s_field=artykul&s_order=ASC&visible_params=2%2C529%2C1335%2C2517%2C665%2C669%2C32%2C657%2C18%2C667%2C673%2C663%2C672%2C661%2C2221%2C423%2C2206%2C681%2C683%2C671&mapped_params=32%3A1451325%2C1629996%3B

It might make sense to use such cables for the hall-sensors, if you want to avoid from them getting destroyed in case the phase wires melt again. Wouldn't save you from a faceplant / blown mosfets, but at least the motor should be safe  ;)  Better take a look at the datasheets though, I have no idea how tight turns (minimum bending radius) these cables can make, and if they can fit through the axle with the phase wires (external diameter).

Edited by esaj
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On 7/26/2019 at 3:22 PM, mrelwood said:

The magnets are strong enough to pull the rotor back in. But I was eventually able to separate them

 

On 7/26/2019 at 4:47 PM, evil696 said:

almost didnt cut my fingers i wouldnt do that again, and it was only 350W motor. If you still want to separete rotor from magnet be careful, seriously.

This is the tool i use for the disassembly of my ebike hub motor 10 years ago ( video for ref )

Spoiler

 

This is how the Chinese factory did it :lol:

Spoiler

 

 

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On 7/16/2019 at 3:31 AM, Marty Backe said:

And what I do with my wheels when given the opportunity, is to use zip ties to keep the motor wires from touching even if they get extremely hot. This is one of my ACM's

IMG_9328

 

They sell "cable combs" that are made for this exact purpose, commonly used in the PC modding community.  It'd look nicer than the zip ties.

 

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1 hour ago, neurokinetik said:

They sell "cable combs" that are made for this exact purpose, commonly used in the PC modding community.  It'd look nicer than the zip ties.

 

Thanks. I wasn't aware of those. In my case I have lots of cable ties and aren't overly concerned about the attractiveness inside the sealed wheel.

But I'll buy some to have on hand next time I'm doing this.

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By the way, if you get into a toasty situation, regular zip ties will snap, melt and desintegrate as well, likely way before the cable shield does. Which is why I had a snapped zip tie running free inside the motor...

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3 hours ago, mrelwood said:

By the way, if you get into a toasty situation, regular zip ties will snap, melt and desintegrate as well, likely way before the cable shield does. Which is why I had a snapped zip tie running free inside the motor...

I only use special high-temperature zip ties.

I kid, I kid :)

Good point, I still think it's better than nothing.

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6 hours ago, mrelwood said:

My MSX is finally operational again, after replacing all motor wiring, hall sensors, and the mainboard. Just came back from a 30km first ride.

 

Congrats, that's some serious work done! :thumbup:

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6 hours ago, mrelwood said:

My MSX is finally operational again, after replacing all motor wiring, hall sensors, and the mainboard. Just came back from a 30km first ride.

 

You're the man! :cheers:

Glad you have your wheel back and running. Now please, pay attention to the wheel current next time you decide to climb Mt Everest ;)

Edited by Marty Backe
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20 minutes ago, Marty Backe said:

You're the man! :cheers:

Glad you have your wheel back and running. Now please, pay attention to the wheel current next time you decide to climb Mt Everest ;)

Thanks Marty!

Come on! The motor wires are now beefier, better shielded, about 40% shorter, and positioned better. NOW I can finally tackle even steeper hills with confidence!

(PS: Kiddin’, I won’t be climbing anywhere steep in the near (or perhaps any) future.)

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  • 4 weeks later...
On 7/15/2019 at 10:23 AM, mrelwood said:

I toasted my MSX yesterday, as I described here. One mosfet blown, but seems that the motor cables would only need proper insulation and separation. Mapping my options.

Replacing a single mosfet

The only place I found the mosfet HY5012 for sale was Aliexpress. A month is a horribly long time to wait, without even being sure if a mosfet replacement is enough. I will ask for a faster shipping option though.

Replacing mosfet with a different model

Another option is to replace the mosfets with a different, western model. IXFX300N20X3 has higher performance ratings across the board (200V, 300A, 1250W, original is 125V, 300A, 500W), but a single mosfet costs 22€. For changing the model, I would think that all 12 should be replaced with the same type. That would make the mosfet replacement more expensive than a complete new board. And the board might not even work.

IRFP4468PBF would only cost 4.63€ per mosfet, although a relatively high shipping fee would be added. This is 100V, 290A, 520W. I would think that the 100V MSX uses the same mosfets, which could leave enough headroom for a 100V mosfet on a 84V MSX. Is the voltage headroom enough?

Then there is the IXFH320N10T2 for 9€ a pop, 100V, 320A, 1000W.

For some reason a few Ali sellers mention IRFP2097 and IRFP4368 in the HY5012 sale item title. But they are both only for 75V. (209/300A, 330/520W).

Replacing the whole mainboard

For purchasing a complete control board my options seem to be limited to Chinese sellers as well, since Speedyfeet has sold out, and other stores I found do not sell Gotway or Gotway parts. A message directly to Gotway? Any shops in EU that I've missed?

 

Any other options? Time to buy a new wheel? (No it isn't.)

In my experience, these outputs work in pairs (push/pull) If one fried (shorted) the other was affected as well and may fry soon after. So if you replace the one, also replace its complement. Also, it is possible that its driver(s) may have fried as well.

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  • 2 years later...
On 7/23/2019 at 1:11 PM, mrelwood said:

I wish I was a drinker.

I "could"  be your sponsor.... The 12 steps can and do actually work....  Fer some peeps .. I guess that's what I heard from this one guy I talked to..... 

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