On Thu, 02 Oct 2008 05:34:47 -0700, Daniel Rudy
wrote:

At about the time of 10/2/2008 4:11 AM, Graz stated the following:
On Thu, 02 Oct 2008 03:59:45 -0700, Daniel Rudy
wrote:

At about the time of 10/2/2008 1:20 AM, Graz stated the following:
The only electronics (on a face plate) attached to the motor are a ST
electronics BTB16 600BW chip (used for phase control in motor speed
controllers) and an unidentified cylindrical component marked only as
"43-02 97C".

Just curious whether the failure of either of these could be causing
the motor failure symptoms in the subject line,
That 43-02 sounds like a motor running capacitor...43uf maybe? The 97C
means that it will function correctly up to 97 degrees Celsius. A
failure of the cap will cause problems.

OK, thanks. I will try to measure the ESR on it. What sort of
problems could failure cause?


Failure to start or trouble starting.

It starts fine, just sparks quite a bit, is noisy, and there's an
electrical burning smell (from the sparks, presumably)

I'm willing to bet the triac is
out. Personally, I would replace both. With that being a motor cap,
you may want to get something in the 250-480v range.

The cap checks out OK. It won't cost me much to replace the triac so
it's worth a shot. I can get hold of a BTA16-600BW (locally) easily
enough, but the BTB16-600BW will be more difficult. According to the
data sheet, the only difference between them is that the "A" is
insulated and the "B" is not, so I imagine I could use the "A"?

The chip mentioned is not a IC
per say, but it's a triac.
http://www.datasheetcatalog.org/data...onics/7471.pdf is
the datasheet on it.

It sounds like the motor is a standard induction motor with a 90 degree
phase controlled startup winding.

Apparently it's also brushless. And not amenable to dissasembly.


Induction motors are brushless, and you can take them apart. I've done
it quite a few times. The stator is just the windings. The rotor is
quite simple, basically just a bunch of steel laminates inside an
aluminum cage. You have bearings on both ends. There isn't much to
them. The only ways that an induction motor can fail is either a
winding opens or shorts (which rarely happens), or the bearings go out
(more common), and that's it. It's kinda unusual to see a low
horsepower induction motor have a separate starting circuit, even if it
is single phase.

It just seemed odd to me that the actual motor on a vacuum cleaner
less than 6 years old would pack up. Especially one made by Miele,
which prides itself on the quality of its products.

Here's some theory if you are interested.
http://www.reliance.com/mtr/mtrthrmn.htm

Thanks for that, bookmarked. All your help much appreciated.