Dead Xlyte 408...help?

[Jozzer]

Hi all, this weekend I finally murdered my old faithfull 408. After many stop/starts and a few hills on a hot day it overheated badly, and as pulling into my drive it started making a high frequency clicking sound (too high freq to be caused by the hubs revolutions, and related to throttle, not motion). After letting it cool somewhat, I tried it again, and it immediatly popped a fuse in the battery pack. I dropped to lower voltage, plugged the motor in again, and it blew another fuse...and another...

Any idea's whats actually happened to it? Any chance its repairable?
Its dissasembled right now, and showing no obvious signs of distress, no smoked wires visible...
How does one go about testing the phase wires ETC?
I'm also assuming that since the fuses only blow when the motor is connected to the controller, that it would be a motor fault, not controller (causing the blown fuses)?
I CAN however finally say how much power the 408 can take continuously (that would be a little less than 2.5KW ) :lol:

 

[The7]

What is the battery voltage and Ah?
What controller is used?

Seems that the motor is OK.

But the controller could be faulty.
If only one section of the FET were burnt and short-circuited, it only would blow the fuse when the motor was connected.

 

[Jozzer]

That wouldn't explain noise, or the fact that it died with severe motor overheat :? Until the noise is explained, I must assume it was the motor.
It sounded something akin to gears slipping...

What tests could I perform on motor and controller that DONT require any power attached?

 

[Rassy]

I know you don't wish to use power, but one test Wilderness Energy suggests to isolate motor/controller problems on a brushed motor is to go directly from a 12 Volt battery to the motor. Either the motor runs or it doesn't. I thought I saw somewhere that a brushless motor would run without hall sensors if it was started manually. If so, the same test might work. Maybe one of the EE types here can help?

 

[Jozzer]

Yeah, Fechter will sort it :lol:
Ok...new info, testing the fets as described in "when things go bang-troubleshooting 101"..
Assuming "powerleads" are the input to the cotroller, I'm reading around 650ohms from all phase wires to the + lead, and nothing (ie no connection at all) to the negative lead...which means dead fet/s?
Errr....I repeated the test just now (mid message) to check readings, and suddenly the opposite is true! Now there is a reading of 650ish from all phase to the NEG lead, and nothing to the POS.
*scrathes head and looks for someone who knows what they are doing*

 

[Lowell]

Try checking the resistances on the motor phases. Opening the motor might give some visual clues as well.

 

[patrick_mahoney]

Yeah, I'd check the resistance of each of the terminals to each other. And then check the resistance of each of the terminals to the case of the motor. The terminals should all have the same resistance to each other, and they should have infinite resistance to the case of the motor.

Brushless motors are actually pretty simple affairs - in fact they are so simple that even though I've made a couple myself, they still seem too easy to actually work as well as they do. There's not a lot that can go wrong with them electrically. Basically the three electrical things that tend to go wrong as the wire will melt it's insulation and short to the case, or two wires will melt their insulation and short to them themselves. Or a wire could break and create an "open" connection. Mechanically there are many more things that can happen, but electrically it's usually one of those three - and all of them are pretty unlikely.

If you look at this manual for building a brushless motor from a kit:
http://www.komodohobby.com/download.asp?fileName=KH-278-v2.pdf

You can see how they are made and the wiring is wound... there's not much to them. Bicycle hub motors are larger, but fundamentally the same design.

 

[Jozzer]

It is dissasembled already Lowell..
phase wire to phase wire, all have similar resistance (0.6-0.9), as do phase wires to ground.
Infinite resistance means open circuit?
What kind of values should I be seeing?
Thanks guys...

Steve

 

[Lowell]

Oops, sounds like the motor windings are ok. Check the hall sensors for switching. From your original post, does that mean the battery fuse only blows when the motor is connected? As in the controller will power up OK with no motor connected?

 

[Jozzer]

Idd thats right, Right now its on, DB stays lit up, measures no draw, with no motor connected. when I plug the motor to the controller one of the battery fuses will pop (30A fuse).
You sure the motor is OK? The phase wire are nearly shorting to the casing, or my head is messed up! (0.9 on a digimultimeter)
Hall sensors wouldn't cause fuse blowing would they?

 

[Lowell]

Since you have a DB, try riding the bike with no battery connected and see if you get a speed reading. On my bike, once you get up a few km/h the motor generates enough voltage to power up the computer, and you can use it like a regular cyclo-computer

Phase wires to the casing I'm not sure about, but 0.9 ohms sounds about right for winding resistance.

 

[The7]

It is dissasembled already Lowell..
phase wire to phase wire, all have similar resistance (0.6-0.9), as do phase wires to ground.
Infinite resistance means open circuit?
What kind of values should I be seeing?
Thanks guys...

Steve

What is the resistance of the phase wire to the casing?
If it is the order of 0.X ohm, then there is a short-circuited between the winding and the casing. Then the motor is faulty.

For this measurement, disconnect all the motor wires from the controller.

 

[Jozzer]

as I said, all phase to case show the same 0.9.
So, if the motor is foobar, how about the contrloller? (please read above before commenting :wink: )

 

[Jozzer]

Hmm, anyone know if all the crystalyte housings are the same? Ie. can I swap out the magneto of my old 4011 into the housing of the dead 408? If I can, It saves stripping 2 wheels and rebuilding 1

 

[Lowell]

As long as they're from the same generation. The newer offset motors will not interchange.

 

[maxwell]

If it has one short to ground in the motor it will run with the rest of the circuitry isolated, any more than that it is dead.

 

[NickF23]

I'm confused. Have you tried hooking the controller up to the 411?

 

[Jozzer]

All phase wires short. How does one go about locating the short? Since all three wires short, is it likely that the short isnt in the windings, but somewhere where all 3 wires passs together?

Hi nick, couldnt rig the 4011 up easily, as its strapped to an enormous wheel (wouldnt fit in the KMX)! But, I tested the controller against the spare and all seems good. I plugged a Puma into it last night also, with no blown fuses! (couldnt get the puma to do more than turn an inch tho, halls wires/phase wire confusion to sort out).
So....it seems I have killed the motor, and the x'lyte controller shows how strong it is! (to survive a dead motor short, whilst running 84v@30A)
I'll try swapping out the 4011 magneto with the dead 408's, just to have a spare motor ready to go in case my Puma experiments take a turn for the worst!
I'll get my puma/BMC back at the weekend all laced up, and have a second one here waiting for a friend also...one way or the other I'll be back on the road for the weekend!

 

[xyster]

And you were running about the same power at which at least one other person (PA forum) reported frying their 4xx...

Conservative hubmotor rule of thumb?

4xx series: 1500 watts continuous; 2500 watts for a few minutes; 100 volts max.

530x series: 3000 watts continuous; 6000 watts for a few minutes; 120 volts max.

BMC/Puma (internally modified with thicker wires): 1500 watts continuous; 2500 watts for a few minutes; ? volts max.

 

[NickF23]

if all 3 wires are connected to each other without any resistance chances are they're connected all connected to the case. sounds like you'll needed to take it apart and find out what's happening, maybe melted cable's. High voltages does wierd things to connections sometimes, surprised you fuses holders have survived. All my original tmk fuse holders are now dead.

Should be pretty straightforward to fix.

 

[NickF23]

double post edited

 

[patrick_mahoney]

Brushless motors don't work if there's a short to the case. Why specifically, I don't know. But when I am winding a 3-phase brushless motor, and I accidently pull a wire too hard against the stator and scrape off the insulation - thus shorting that wire to the stator (which then shorts it to the case) - then the motor won't work. Not even a little. That's been my experience anyway - and the types of motors that I work with are much smaller than these hub motors, but they are pretty much identical in terms of the way they work.

 

[Jozzer]

Indeed, after finishing the post mortem it is easy to see where it blew, several of the windings made contact with the casing, and arced a nice groove there, before blowing completly and parting company with itself. I'll try and post some pics over the weekend.
I popped the 4011 windings in the old hub, and sure enough it works. I'm not entirely convinced that its not rubbing just a little inside (fit isn't perfect perhaps). Worked well enough for me to know that my Lucky Controller (for that shall be its name for all eternity) is indeed alive and well Roll on Puma!
Xyster, I'd say that the 40X can take much more than a few mins at 2500w at speed (ie 30MPH fighting wind), but 2500w of inefficient lowspeedriding/hillclimbing will cook it in 15 mins or so. I have been using 2500w on this motor for months, and only because of the silly stuntpractice did it fry, and still then on a hot day. Entirely my fault I feel, and I am going to do my best to fit a temp guage to all my future "subjects" so I can tell when thermal runaway sets in!

THanks for your help guys..