[modeleng] Re: voltage controll

Thank you for this,
To answer one question
"especially if we are talking high voltage and power components (unless 
this is your speciality)."

yes it is...



It is a matter of design, as these things have to dissipate way too much 
heat, and are made of components that are what we call "borderline 
spec". The dimensioning of the semiconductors leaves almost nothing as a 
margin.
On top of this flaw (done for 'the cheap') the embedding in 'the gunk' 
mentioned makes sure that the heat cann't go anywhere. So 
transistors/triacs or thyristors call it a day....for good.
Imagine the cooler of your CPU in the very computer you use to,so 
kindly,share your ideas with me is packed in silicone! It wouldn't last 
long enough to read the answer to this message...
The cooling fins of the thyristors are on top of being packed in resin, 
so small, that they are, in short; useless. this is done to make the 
unit fit inside the generator head. This is ,next to the diesel, the 
hottest part of the genset.
The people who make these sets, have by admission of one of there own 
technicians, changed the place were they mount this unit.(outside the 
gen head)
Not because they want to keep it cooler, but because it takes too much 
time to dismantel the units (they seem to have to do a lot of that...)
The system of self exiting generator heads is a good one ,in concept, it 
cals for little repairs.
So the manufacturers have to generate some trade in spare parts. This is 
one way of doing it.


Many thanks
Regards
Patrick








R.L. Roebuck wrote:

>Hi there Partick,
>
>If I was tackling this myself, then I would possibly be thinking along 
>the following lines. I may be wrong, but this is what my thoughts are...
>
>Is this a common problem for other people using these 
>generator sets - if so you'd think that there'd be other peoples comments 
>about it online for the make you have.
>
>If not, is it worth making sure you don't think it's something you're 
>doing that's blowing it - 3 times is usually my limit for smoking bits 
>before I sit down and have a few cups of tea, and run it past a colleague.
>
>If you're happy it's a problem with this make of AVR then is there any 
>sense in buying an AVR for a different make of generator set, one with a 
>better reputation?
>
>If not, then you're implying that all such AVR's have this kind of 
>problem, and so no matter how much skill you have in the field, it will 
>count for nothing, as you're looking at a reaearch and development 
>problem, and you will doubtless spend more money on blown components in 
>testing and trying that it will cost you to buy a handful of new AVR's - 
>especially if we are talking high voltage and power components (unless 
>this is your speciality).
>
>You will also end up spending valuable workshop time doing what you do all 
>day at work.
>
>...it may be more of a reality check than what you were looking for - but 
>I thought I'd put 'pen to paper' just incase the thoughts were of any use.
>
>
>Yours,
>
>
>Rich.
>
>  
>
>>----- Original Message -----
>>From: "Patrick Coppens- Marian Lynch" <sb286643@xxxxxxxxx>
>>To: <modeleng@xxxxxxxxxxxxx>
>>Sent: Tuesday, March 27, 2007 4:21 PM
>>Subject: [modeleng] voltage controll
>>
>>
>>    
>>
>>>Evnin' All
>>>
>>>I my Workshop, I have a 3 phase (6,5KVA) diesel genset.
>>>This provides the current for my (big ) lathe and a number of other 3
>>>phase motors.
>>>For the 3rd time the AVR (automatic voltage controller) has clapped out.
>>>At 100 euro's a pop, yours truly is fed up.
>>>I am an electronics engineer, so I can design/ make a more robust one
>>>myself, but it would help to have a circuit diagram of one.
>>>The commercial ones are embedded in a sort of gunk ,to protect them from
>>>moisture and prying eyes like mine...
>>>So it is impossible to get that stuff of, without totaly mangeling to
>>>circuitboard.
>>>I did that anway, only to find out, that most of the components have no
>>>serial/type numbers
>>>Even the resistors are not colorcoded!
>>>Any body any ideas?
>>>
>>>Patrick
>>>Flanders
>>>MODEL ENGINEERING DISCUSSION LIST.
>>>
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>>>
>>>
>>>--
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>>>Checked by AVG Free Edition.
>>>Version: 7.5.446 / Virus Database: 268.18.18/734 - Release Date:
>>>26/03/2007 14:31
>>>
>>>      
>>>
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>MODEL ENGINEERING DISCUSSION LIST.
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>  
>


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