Root cause insight into the common BMW blower motor resistor

On 03/21/2013 08:22 AM, Nate Nagel wrote:
On 03/21/2013 10:41 AM, jim beam wrote:
On 03/21/2013 06:59 AM, Nate Nagel wrote:
On 03/21/2013 09:55 AM, jim beam wrote:
On 03/21/2013 04:52 AM, Nate Nagel wrote:
On 03/21/2013 06:55 AM, the will wrote:
Blower motor drawing too much amperage taking it out. Change the
blower motor anytime?


My thought as well. Have you measured current draw on a new blower
motor and compared it to one that is installed in a car where the FSU
has failed? that would tell you whether there's any merit to this
idea
or not.

for an "engineer", you're simply not of this planet.


Did you have any suggestions for the OP, or did you just show up to
snipe without contributing anything as per usual?

https://groups.google.com/group/rec.autos.tech/msg/1870e822d74b0a5c?dmode=source&output=gplain&noredirect&pli=1



link times out?
then use the message id within the link, retard.


retard.



You do know that most electrical/electronic components have a maximum
current rating, yes? And that electric motors tend to draw more current
when the bearings are going or they are otherwise subjected to loads
higher than that for which they were designed? Does any of this sound
remotely familiar to you?

don't lecture me on electronics nate.

ooh, or what? ITG gonna kick my ass? Sorry, I'm more interested in
helping the OP than your delicate little feelers.
no, don't lecture me on stuff that you clearly don't have the first clue
about.

see above. retard.


Really, what the will suggested seems to be a logical first step.

if you don't know what the FUCK you're doing and don't know how to use a
dvm.


WTF is that supposed to mean?
it means that, if you know what you're looking at, a dvm can tell you
most of what you need to know here.


OP can dissect the thing all he wants but it doesn't do him a damn bit
of good to know *what* has failed unless he knows *why* it failed.
all he needs to know, retard, is that the unit failed and that he needs
to replace it. just like a light bulb.

more than that though, i also told the op how they can go about
establishing a permanent solution, but you're too fucking retarded to
read that or understand it.


--
fact check required
 
On 03/21/2013 04:12 PM, Bimmer Owner wrote:
On Thu, 21 Mar 2013 21:56:49 +0000, mroberds wrote:

It may also be interesting to have some kind of thermometer
on the FSU case ...

That seems like an EXCELLENT idea,
won't save the unit, just a frozen motor.


if we can put some kind
of temperature indicator in the FSU tines, then we can observe
what the temperature is in situ - which might tell us something
about what is overheating these things (assuming heat is the culprit).
you can run the unit out of the fan housing - hold it in your hand and
you'll soon find out if it's getting hot or not.


--
fact check required
 
On 03/21/2013 08:57 AM, Bimmer Owner wrote:
On Wed, 20 Mar 2013 23:17:36 -0700, jim beam wrote:

analyze the actual problem - don't just waste money replacing stuff.

That's exactly what we've done - yet - we need help since nobody to
date has figured out HOW to test an FSU that is fried.
http://www.bimmerfest.com/forums/showthread.php?t=678534
it's like testing a dead light bulb.


Note: It appears to be an active component, but it probably does
dissipate 100W.
it dissipates Vd x Im where Vd = voltage drop across the unit output,
and Im = current drawn by motor. it will indeed get hotter when running
the motor slower because of the greater voltage drop across the unit.
that's why pwm is the better solution - the semiconductors are either
fully on [minimal heat dissipation] or fully off [minimal heat
dissipation]. the only time they get to dissipate heat is during
switching which is a sub-millisecond event and a tiny percentage of the
base time.


--
fact check required
 
On 03/21/2013 05:01 PM, clare@snyder.on.ca wrote:
On Thu, 21 Mar 2013 16:59:01 -0400, "tm" <No_one_home@white-house.gov
wrote:


"Scott Dorsey" <kludge@panix.com> wrote in message
news:kifmfo$7l$1@panix2.panix.com...
Bimmer Owner <dontaskfor@mymail.com> wrote:
On Thu, 21 Mar 2013 11:45:54 -0400, Scott Dorsey wrote:

Static resistance doesn't tell you anything, but operating current
measured with a DMM would tell you a lot.

It 'can' be done, but would require a test jig inserted inline
as the FSU is deeply ensconced under the dash while the blower motor
is even more deeply so.

I don't know the wiring diagram on that particular model, so I don't know
where you would need to break in to measure just the current of the blower
without anything else. But it does not seem terribly insurmountable,
especially seeing that BMW is very good about breaking everything out into
connectors all over.


Just measure the battery current with and without the blower running.

Turn every thing else off.


QED
Just put your ammeter into the heater blower fuse connector and you
get the current of the blower motor.
what he said.


--
fact check required
 
On 03/21/2013 05:08 PM, clare@snyder.on.ca wrote:
On Thu, 21 Mar 2013 22:54:59 +0000 (UTC), Bimmer Owner
dontaskfor@mymail.com> wrote:

On Thu, 21 Mar 2013 15:03:45 -0700, Ashton Crusher wrote:

If it's being blown by intermittent high current draws the
fuse could protect the $100 FSU.

That's an interesting idea. The FSU supposedly consumes the
most power when the blower motor is set to the LOW settings
(simply because it has to dissipate the power as heat), so,
we could prevent excess current by fusing... say with a 10A
fuse, the blower motor (which is said to consume 5 to 6 A).
So the crafty germans are using a high tech solid state resistor
instead of a PWM speed controller???

If I had one and it blew I think I'd be designing a PWM controller to
take it's place. Need to find out what kind of signal the controller
expects, but that shouldn't be too difficult.
indeed.


--
fact check required
 
On 03/21/2013 10:07 PM, jim beam wrote:
On 03/21/2013 09:00 AM, Bimmer Owner wrote:
On Thu, 21 Mar 2013 08:14:12 -0700, jim beam wrote:

it's cheaper to just buy a new one.

To be clear, that's what 99.99999999% of the BMW owners do.
But that's not the point of this thread.

The point of this thread is to get a handle on WHY they are all
failing.

i already told you - it's overheating. semiconductors don't like heat.
Yeah, we know that.

*why* is it overheating?

Specifically, how to figure that out is the question.

knowing how the light bulb blew doesn't fix it.
But it may make the replacement last longer.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
 
Bimmer Owner <dontaskfor@mymail.com> wrote:
On Thu, 21 Mar 2013 15:16:46 -0400, Scott Dorsey wrote:
has anyone got docs on that mystery IC there? It's from Elmos
Semiconductor, but it's not a standard Elmos part number on it

Focusing just on that Elmos Semiconductor AG IC from this thread:
http://www.bimmerfest.com/forums/showthread.php?t=309399
It looks like the PN is ELMOS, 10901D, 667A 1302A

It might be a generic or a special chip; I can't find it on the web:
http://www.elmos.com/produkte/automotive/motor-control/dc-motor-ics.html
All the standard Elmos part numbers begin with an E.

My guess is that the number on the chip is 10901D and that the other
two numbers are date and batch codes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
On 03/21/2013 07:23 PM, Nate Nagel wrote:
On 03/21/2013 10:07 PM, jim beam wrote:
On 03/21/2013 09:00 AM, Bimmer Owner wrote:
On Thu, 21 Mar 2013 08:14:12 -0700, jim beam wrote:

it's cheaper to just buy a new one.

To be clear, that's what 99.99999999% of the BMW owners do.
But that's not the point of this thread.

The point of this thread is to get a handle on WHY they are all
failing.

i already told you - it's overheating. semiconductors don't like heat.


Yeah, we know that.

*why* is it overheating?
because it's linear, retard. if you don't know what they means, fuck
off until you find out.


Specifically, how to figure that out is the question.

knowing how the light bulb blew doesn't fix it.

But it may make the replacement last longer.
putting facts in front you dumb ass all day long doesn't make you any
smarter.


--
fact check required
 
On Mar 20, 11:08 pm, Bimmer Owner <dontask...@mymail.com> wrote:
Does anyone have insight into what is the root cause (and repair) of the
FSU failure that plagues almost every 1997 to 2003 BMW?
 http://www.bimmerfest.com/forums/attachment.php?attachmentid=126060&d...

Also, does anyone have an idea HOW TO TEST a "repaired" FSU?

The "blower motor resistor", which also goes by FSR (Final Stage Resistor)
or by FSU (Final Stage Unit), is known to fry itself in almost every single
E46 (3-series), E39 (5-series), and E38 (7-series) BMW.
 http://www.bimmerfest.com/forums/showthread.php?t=143393

The problem with replacing this ~$100 part is that the new replacement FSU
fries itself just as often as the old one did, so you end up repeatedly
replacing your fried FSU every few years or so.
 http://www.bimmerfest.com/forums/showthread.php?t=528566

That's fine for most people (although the DIY is a PITA) - but I ask
this newsgroup whether anyone has any insight into WHAT is actually
breaking - and - why?
 http://www.bimmerfest.com/forums/showthread.php?t=309399

Here is the best (admittedly sketchy) wiring diagram we have so far:
 http://www1.picturepush.com/photo/a/12467819/img/12467819.png
I had a dodge caravan that fried its heater AC motor speed control
resistor repeatedly....

the connector to the wiring harness detoriates from the high current
and the voltage drop causes the connector to heat up and the entire
assembly fails.

Oddly enough I repair roll laminators that apply plastic film to paper
think menus:)

laminators experience similiar failures so I did the following.

Purchased a new resistor block, soldered wires on all the connectors
putting a heavy wire on each one.... Put a pigtail on each one.
Installed resistor block. Its screwerd to the fire wall.

Cut the plug assembly off the harness, stripped all wires, twisted
them together and installed wire nuts on each one.

had the van for years with zero problems for this part:)
 
On 03/21/2013 07:39 PM, Bimmer Owner wrote:
On Thu, 21 Mar 2013 19:15:16 -0700, jim beam wrote:

that's why pwm is the better solution

Does pulse width modulation cause radio EMI?
it can if the radio isn't very noise resistant and the switching is
"hard". you won't typically hear it on the fm bands, but you might on
the am.

you can make a pwm unit "soft switch" and kill pretty much all of the
electrical noise it would otherwise generate and incur only a very small
heating penalty.


--
fact check required
 
On 03/21/2013 10:25 PM, jim beam wrote:
On 03/21/2013 07:23 PM, Nate Nagel wrote:
On 03/21/2013 10:07 PM, jim beam wrote:
On 03/21/2013 09:00 AM, Bimmer Owner wrote:
On Thu, 21 Mar 2013 08:14:12 -0700, jim beam wrote:

it's cheaper to just buy a new one.

To be clear, that's what 99.99999999% of the BMW owners do.
But that's not the point of this thread.

The point of this thread is to get a handle on WHY they are all
failing.

i already told you - it's overheating. semiconductors don't like heat.


Yeah, we know that.

*why* is it overheating?

because it's linear, retard. if you don't know what they means, fuck
off until you find out.
so "because it's linear" it by nature overheats to the point of failure?
Odd, I'm pretty sure that that controller worked initially on, well,
all of the vehicles in which it was originally installed.

The question is, is it overheating to the point of failure because the
designer cut things too fine (in which case designing a better part
would be the right approach), or is it because there's another issue
somewhere else *causing* a part that would otherwise have acceptable
service life to fail (in which case replacing it with a stock
replacement and fixing the underlying issue would be the most economical
thing to do)?


Specifically, how to figure that out is the question.

knowing how the light bulb blew doesn't fix it.

But it may make the replacement last longer.

putting facts in front you dumb ass all day long doesn't make you any
smarter.
IKYABWAI.

It would really be just like you to spend all day designing a more
robust controller, building it, watching it too burn up, and then
realize that the problem was something else, like a chronic problem with
dry fan motor bushings, windings dragging on the case, something like that.

But sure, don't check the obvious stuff, just go into your long-winded
sometimes technically correct and sometimes not babble, I know that
anything I say won't stop you anyway.

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
 
In article <kigfbd$nq7$2@dont-email.me>, jim beam <me@privacy.net> wrote:
On 03/21/2013 07:23 PM, Nate Nagel wrote:

*why* is it overheating?

because it's linear, retard. if you don't know what they means, fuck
off until you find out.
Nothing wrong with linear motor control, it's just inefficient and
produces a lot of heat. I used to work in a place with a 1.2 MW DC
motor whose field coil voltage was controlled by a couple rooms full
of cast-iron resistors. The resistance array lasted nearly 80 years
before the whole facility was taken down.

As long as you keep within the safe operating area of the semiconductors,
you're fine. If you exceed them, bad things happen. But we don't know
if the semiconductors are failing on these things, or if it's just
ordinary RoHS solder failures; the RoHS crap doesn't like thermal cycling
so well.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
Bimmer Owner <dontaskfor@mymail.com> wrote:
On Thu, 21 Mar 2013 19:15:16 -0700, jim beam wrote:

that's why pwm is the better solution

Does pulse width modulation cause radio EMI?
It can if it's not properly filtered. And the reason why I think beam is
correct about this being a linear control is that there is no filtration
in there.

My guess is that the cost of proper filtering and shielding makes the pwm
controller cost more than the linear controller in this case, which is
probably why they went the linear route.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
On 03/21/2013 07:53 PM, Nate "anosognosic" Nagel bleated:
<snip drivel>
It would really be just like you to spend all day designing a more
robust controller, building it, watching it too burn up, and then
realize that the problem was something else,
um, no, it would be me building something that worked first time. and
that has stayed working.

but you wouldn't know that because you're an unspeakable hamster brained
retard that hasn't got the slightest clue the FUCK they're talking
about, much less the ability to click on a link and READ it.


like a chronic problem with
dry fan motor bushings, windings dragging on the case, something like that.
which are entirely fucking different, and don't fucking disappear after
the controller has been changed.


But sure, don't check the obvious stuff, just go into your long-winded
sometimes technically correct and sometimes not babble, I know that
anything I say won't stop you anyway.
i wish something would stop you. like self-awareness.


--
fact check required
 
On 03/21/2013 08:08 PM, Scott Dorsey wrote:
In article <kigfbd$nq7$2@dont-email.me>, jim beam <me@privacy.net> wrote:
On 03/21/2013 07:23 PM, Nate Nagel wrote:

*why* is it overheating?

because it's linear, retard. if you don't know what they means, fuck
off until you find out.

Nothing wrong with linear motor control, it's just inefficient and
produces a lot of heat.
right, but what's the point in using 140W to run a 60W motor? and
/certainly/ not when the devices to do so are so cheap and abundant. i
can see doing it back in the day when there weren't any other options,
but today there are, and there have been for 20+ years.


I used to work in a place with a 1.2 MW DC
motor whose field coil voltage was controlled by a couple rooms full
of cast-iron resistors. The resistance array lasted nearly 80 years
before the whole facility was taken down.

As long as you keep within the safe operating area of the semiconductors,
you're fine. If you exceed them, bad things happen.
right. but again, we're dealing with mba's here. as an engineer,
you're going to design with reliability and a safety margin built in.
as an mba, you're going to cut and keep cutting until it meets "business
objectives".


But we don't know
if the semiconductors are failing on these things, or if it's just
ordinary RoHS solder failures; the RoHS crap doesn't like thermal cycling
so well.
very true. but at the end of the day, that's still heat. and a linear
semiconductor controller is just stooopid when a wire coil will do the
same job more reliably and at a fraction of the cost.


--
fact check required
 
On 03/21/2013 08:10 PM, Scott Dorsey wrote:
Bimmer Owner <dontaskfor@mymail.com> wrote:
On Thu, 21 Mar 2013 19:15:16 -0700, jim beam wrote:

that's why pwm is the better solution

Does pulse width modulation cause radio EMI?

It can if it's not properly filtered. And the reason why I think beam is
correct about this being a linear control is that there is no filtration
in there.
it's the heat sink that's the dead give-away. a pwm controller heatsink
would be 1/10th the capacity. or less.


My guess is that the cost of proper filtering and shielding makes the pwm
controller cost more than the linear controller in this case, which is
probably why they went the linear route.
i think the cost of that honking great heatsink significantly exceeds
the cost of a couple of extra inductors and caps.


--
fact check required
 
On Thu, 21 Mar 2013 19:15:16 -0700, jim beam wrote:

that's why pwm is the better solution
Does pulse width modulation cause radio EMI?
 
On Thu, 21 Mar 2013 20:01:20 -0400, clare wrote:

Just put your ammeter into the heater blower fuse connector and you
get the current of the blower motor.
That's an interesting idea.
http://www3.picturepush.com/photo/a/12475041/img/12475041.jpg

The fuse for the blower motor is called the "infamous F76" for a reason.
http://bimmerfest.com/forums/showthread.php?t=674612

It's a 40 amp fuse under the glovebox but it's in a really inaccessible
spot; however, it's right side up, so, the wires going INTO it are
visible from the tips of your feet under the glove box.

So that's a possibility; but you'd have to cut the wires.
http://www5.picturepush.com/photo/a/12475043/img/12475043.jpg
 
On Thu, 21 Mar 2013 22:54:59 +0000 (UTC), Bimmer Owner
<dontaskfor@mymail.com> wrote:

On Thu, 21 Mar 2013 15:03:45 -0700, Ashton Crusher wrote:

If it's being blown by intermittent high current draws the
fuse could protect the $100 FSU.

That's an interesting idea. The FSU supposedly consumes the
most power when the blower motor is set to the LOW settings
(simply because it has to dissipate the power as heat), so,
we could prevent excess current by fusing... say with a 10A
fuse, the blower motor (which is said to consume 5 to 6 A).
Hmm, it did look like it had quite a heat sink. I had assumed it used
PWM to change speed, which should not generate much heat but my
assumption might be wrong (or my understanding of PWM...) A solid
state design that gets hot on purpose seems like a poor design to me.
 
On Mar 21, 10:25 pm, klu...@panix.com (Scott Dorsey) wrote:
Bimmer Owner  <dontask...@mymail.com> wrote:

On Thu, 21 Mar 2013 15:16:46 -0400, Scott Dorsey wrote:
has anyone got docs on that mystery IC there?  It's from Elmos
Semiconductor, but it's not a standard Elmos part number on it

Focusing just on that Elmos Semiconductor AG IC from this thread:
http://www.bimmerfest.com/forums/showthread.php?t=309399
It looks like the PN is ELMOS, 10901D, 667A 1302A

It might be a generic or a special chip; I can't find it on the web:
http://www.elmos.com/produkte/automotive/motor-control/dc-motor-ics.html

All the standard Elmos part numbers begin with an E.

My guess is that the number on the chip is 10901D and that the other
two numbers are date and batch codes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
If you google for 10901D it comes back with hits to
Chinese chip brokers that show it as an Elmos 16
pin surface mount chip. Which is consistent with what's
in the picture of the failed module, it has 16 pins.
But I could not find any data sheet on the part either.
 

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