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good point - how much? sure, big motor coils, big inductors -so how toamdx wrote:
that looks like a linear semiconductor controller - an incredibly
antiquated concept for a modern car.
well, you live and learn. apparently the reason they use a linear
controller is because it allows the fan to run near silently at low
speed. with pwm control the fluctuating magnetic fields in the
motor >coils cause it to vibrate and make a humming noise at the pwm
control >frequency.
that doesn't of course get around the fact that the unit in question
here is apparently badly under rated, but the above does at least
explain why it's used.
I see many Motor Speed Control Manufacturers upped their PWM
frequency to be between 16 K to 22 K to eliminate much of the noise.
Mikek
Sure, if you don't mind heating the motor up...
Jamie
if it's just a two-layer board, maybe. assuming you get the specs onScott Dorsey wrote:
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
tm wrote:
Are you sure it is not already a pulse width regulator? Those transistors
look like they are TO-220 packages, not TO-3.
I've seen 20W power resistors in TO-220 packages.
It does indeed look like a TO-220 from the pin spacing (since there are no
actual transistors in the photos, just spots from which they were removed).
All those photos only show one side. I full reverse engineering
should be done to draw a full schematic but I've never had my hands on
that module. It would probably take a couple of them, because ot the
potting.
/and/ a smaller footprint. the "because" is entirely due to the softBut if it had been a PWM device, there would have been some filtering in
there, inductors and capacitors to keep the noise from getting into the
power lines. Designing clean and quiet PWM controllers is not quite as
trivial as some folks have made it out to be.
Have you looked at the National Semiconductor (Now part of T.I)
'Simple Switcher' series of controllers? Generally only one inductor
and a couple small electrolytics. A lot simpler than older designs, and
little noise because of the small footprint.
PWM has been around longer than SMT parts.
Maybe it is transients from the motor that are causing the failures.
This is possible, if it is the transistors that are failing. I don't see
any big protection diodes in there either.
If it's a RoHS soldering issue, though, I would not be surprised.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
The more you rub off, the quieter the motor is! You start throwing stuffOn 03/25/2013 06:59 AM, Scott Dorsey wrote:
In article <kin5r4$pi1$1@dont-email.me>, jim beam <me@privacy.net> wrote:
well, you live and learn. apparently the reason they use a linear
controller is because it allows the fan to run near silently at low
speed. with pwm control the fluctuating magnetic fields in the motor
coils cause it to vibrate and make a humming noise at the pwm control
frequency.
Yes, this is why you put an integrator stage after the pwm stage, so that
the motor sees nice filtered DC with very little of the PWM leftover.
Problem is that the integrator stage costs money and big electrolytics
tend to have limited life, so auto folks don't like doing that.
you don't want to integrate the output, merely rub the shoulders off the
square waves to get the harmonics down. the whole point and benefit of
pwm is that you have full voltage full power available in each pulse.
that's how you can start and control a motor with high torque at low
rpm. if you integrate or smooth out the motor's supply, you effectively
lose that and the motor won't start or torque the same way or even at all.
true, but you don't want to "integrate" the full power individual pulsesIn article <kipocc$2kn$1@dont-email.me>, jim beam <me@privacy.net> wrote:
On 03/25/2013 06:59 AM, Scott Dorsey wrote:
In article <kin5r4$pi1$1@dont-email.me>, jim beam <me@privacy.net> wrote:
well, you live and learn. apparently the reason they use a linear
controller is because it allows the fan to run near silently at low
speed. with pwm control the fluctuating magnetic fields in the motor
coils cause it to vibrate and make a humming noise at the pwm control
frequency.
Yes, this is why you put an integrator stage after the pwm stage, so that
the motor sees nice filtered DC with very little of the PWM leftover.
Problem is that the integrator stage costs money and big electrolytics
tend to have limited life, so auto folks don't like doing that.
you don't want to integrate the output, merely rub the shoulders off the
square waves to get the harmonics down. the whole point and benefit of
pwm is that you have full voltage full power available in each pulse.
that's how you can start and control a motor with high torque at low
rpm. if you integrate or smooth out the motor's supply, you effectively
lose that and the motor won't start or torque the same way or even at all.
The more you rub off, the quieter the motor is!
they whine pretty effectively at centihertz too.You start throwing stuff
in the KHz range into the motor, and it whines from magnetostriction.
they will surely complain if it doesn't run.The more of that you remove, the quieter it goes. Of course, if you make
it too quiet, people complain....
So go back to measuring at the battery terminals. Do you have or can youOn Fri, 22 Mar 2013 15:04:39 -0400, clare wrote:
So that's a possibility; but you'd have to cut the wires.
http://www5.picturepush.com/photo/a/12475043/img/12475043.jpg
Why would you have to cut the wires????
Simply remove the fuse and connect the ammeter. You guys make your
lives so difficult
The 40 amp fuse is barely accessible (as can be seen from the photos).
It's not even easy to pull the fuse & even harder to replace it.
So, all I was saying was that it's actually rather difficult to insert
test leads into the empty fuse #F76 fuse holder.
I'd wager it 'can' be done - it's just going to take an hour or so
to get the leads in place.
Are there any other pictures of the module showing if or where theOn Sun, 24 Mar 2013 09:24:13 -0400, Scott Dorsey wrote:
It does indeed look like a TO-220 from the pin spacing (since there are
no
actual transistors in the photos, just spots from which they were
removed).
I doubt anything was removed since all the authors of those pictures
are expressly NOT trying to remove anything.
Those round metal "dots" in the pictures are the five pin connectors
of the harness connector.
and in about 5 or 10 minutes with it.On Fri, 22 Mar 2013 15:04:39 -0400, clare wrote:
So that's a possibility; but you'd have to cut the wires.
http://www5.picturepush.com/photo/a/12475043/img/12475043.jpg
Why would you have to cut the wires????
Simply remove the fuse and connect the ammeter. You guys make your
lives so difficult
The 40 amp fuse is barely accessible (as can be seen from the photos).
It's not even easy to pull the fuse & even harder to replace it.
So, all I was saying was that it's actually rather difficult to insert
test leads into the empty fuse #F76 fuse holder.
I'd wager it 'can' be done - it's just going to take an hour or so
to get the leads in place.
Bet I can do it in less than half an hour - without the MaxiTester
The 40 amp fuse is barely accessible (as can be seen from the photos).So that's a possibility; but you'd have to cut the wires.
http://www5.picturepush.com/photo/a/12475043/img/12475043.jpg
Why would you have to cut the wires????
Simply remove the fuse and connect the ammeter. You guys make your
lives so difficult
That's an idea.Take a blown fuse and use it for a test connector
I doubt anything was removed since all the authors of those picturesIt does indeed look like a TO-220 from the pin spacing (since there are no
actual transistors in the photos, just spots from which they were removed).
or run out of oil, because of all the problems with "ancilliaryOn Sat, 23 Mar 2013 07:20:44 -0700, jim beam wrote:
serious question - why did you buy it?
As for me, I fell sway to all the people saying how great the bimmer was.
It was only after I owned it, that I realized that BMW engineers knew
how to design a suspension and a drive train, but they had no idea
how to build a machine.
To their credit, some people say it's not the engineers fault as
they probably know by now that every single Bosch 5.7 ABS control
module fried in every one of the vehicles it was placed in, and that
the final stage unit cooked itself to death in every single BMW it
was ever placed in, and that the 2-bar plastic cooling system
sprang a leak on almost every single BMW ever built, etc.
In fact, there's absolutely NO WAY BMW can't know about these
egregious engineering flaws. So, the common conclusion is that
their customers don't care - so why should they.
To me, it smacks of 3rd-grade engineering from BMW, so, that's why
I, for one, am amazed (being an owner myself), how sophomoric BMW
engineering really is.
Disclaimer: Yet, the drive train is phenomenal!
If the engine desnt burn to the ground due to oil leaks, or overheat
These photos show both sides.All those photos only show one side. I full reverse engineering
should be done to draw a full schematic but I've never had my hands on
that module. It would probably take a couple of them, because ot the
potting.
That makes a lot of sense!If it's just a typical DC motor with two leads, apply 12V and
it should run full speed. You could [then] measure how many amps
it draws when running.
Of course. Nothing I've ever written is not well documented.Have you got a link to these "common problems" you keep posting about?
As for me, I fell sway to all the people saying how great the bimmer was.serious question - why did you buy it?
I'd be very happy to see pictures of the test leads in situI'd wager it 'can' be done - it's just going to take an hour or so
to get the leads in place.
Bet I can do it in less than half an hour - without the MaxiTester
and in about 5 or 10 minutes with it.
All I have are the following:Has anyone ever fully dissected the unit so you can see what is under the PC
board? Maybe an X-ray from several angles done at the dentist?
Okay, notice on the lefthand photo, there are two sets of three solder jointsCan you circle one of these pictures to show WHERE you think
something was removed?
http://www.bimmerfest.com/forums/attachment.php?attachmentid=367580&d=1363957253
What does ROHS mean?that reduces the probability of it being rohs
Yes, what Scott said. Where are the two transistors that were soldered inBimmer Owner <dontaskfor@mymail.com> wrote:
Can you circle one of these pictures to show WHERE you think
something was removed?
http://www.bimmerfest.com/forums/attachment.php?attachmentid=367580&d=1363957253
Okay, notice on the lefthand photo, there are two sets of three solder
joints
on the lefthand side of the board, which show signs of recent rework.
There
are TO-220 transistors attached to them, which are behind the board and
you
cannot see.
On the righthand photo the board is reversed... you can see two sets of
three
holes on the righthand side of the board which is where those TO-220
transistors were attached. You can see that they overheated the board and
lifted pads in the process too.
But you cannot in either of these photos see the transistors or what the
part
number on the face of them is. Knowing what kind of transistors are used
will go far toward explaining some possible failure modes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."