Re: [CAD_CAM_EDM_DRO] Technical help was Cap voltage rating (was Re:Power supply question.....

One other point here - many applications engineers also have the
discretion to send you engineering samples i.e. small qty's of a
product. Again it doesn't have to be for a big project with huge qty's
- you just have to sound like you are genuinely trying to learn about or
evaluate or apply their product to your application. Just like asking
for technical catalogues (I do and I 've got lotz) - it never hurts to
ask if there are any "engineering samples" available for this product.

Example: I recently needed some big heatsinks for my Geckos and
contacted the manufacturer (R-Theta) and after establishing rapport (and
a bit of schmoozing) and asking some questions about dimensions, heat
transfer coeff etc. that were't clear from their website, I indicated
that I wasn't sure where to purchase small quanitities etc. and could I
purchase direct etc. He indicated it was too much trouble to prepare an
invoice for small quantities and I could have them as engineering
samples if I would pick them up or pay for shipping. (I picked them up
later that day before anyone changed their mind...) Because of such good
service, I have recommended their products to several colleagues - so
hopefully the company's good deed has been rewarded.

Don't expect freebies or catalogues - but ask politely - you'll be
amazed at what's out there for free...

Cheers, Peter


Sven Peter wrote:

> I may second Ballendo here. This method works out very good and if you
> have a little technical background yourself, you FEEL after a few
> sentences if the guy on the other side of the line is sitting firm in
> his saddle or is just muculature. To the experts word it is good to
> listen.
> Good luck
> Sven Peter
>
> ballendo wrote:
>
>>Dave,
>>
>>It's been awhile since I sounded this app engineer "horn" so here
>>goes...
>>
>>I find that the most reliable and easily had information when trying
>>to answer a question like this is to call a major mfr of the product
>>in question (like Mallory for capacitors). Notice I'm talking about
>>the original SOURCE manufacturer, NOT a distributor. Then ask for a
>>TECHNICAL applications engineer. (The word engineer is used more
>>often nowadays; be SURE you are talking to a REAL "applications"
>>ENGINEER. If possible. See the p.s. below) Mention that you are
>>trying to determine which of their parts or products (capacitors in
>>this case) will be right for your "project" (power supply here).
>>
>>It can help to be "calling from" and "for your business" and speak to
>>them as a professional. I'm NOT saying you need to BS them, or
>>pretend to understand everything they are telling you! The job of an
>>applications engineer is to provide technical assistance for those
>>trying to use his or her companys' products correctly and
>>successfully... And believe me, the app engineer HAS spoken to
>>people with less of a "clue" than you...
>>
>>Don't be afraid to appear "dumb". This person is SUPPOSED to know
>>more than you! I have learnt a great deal from these professional men
>>and women. They have often gone out of their way for me; even when
>>they know it is for a small order or use. Most people like to share
>>what they are passionate about; or knowledgeable in.
>>
>>But if it IS for a larger project(volume for the mfr), be sure that
>>fact is mentioned...
>>
>>IMO, The best way to determine if the info you have been given
>>is "good" is to make at least three calls to different competitive
>>mfrs. Like getting second opinions from healthcare or legal
>>professionals...
>>
>>Hope this helps,
>>
>>Ballendo
>>
>>P.S. There ARE some good "app" engineers in sales positions. The
>>smaller the company, the more "hats" each individual wears... And
>>although it may be less expensive to use email, I find that I have
>>better results with phone conversations. Very often, the app engineer
>>WILL THEN direct me to a webpage or site for more info, or to prepare
>>me to ask better questions...
>>
>>--- In CAD_CAM_EDM_DRO@y..., "dave_ace_me" <davemucha@j...> wrote:
>>
>>>Hi Scott and all,
>>>
>>>I've been reading the threads about power supplies and caps and
>>>transformers and all with great interest.
>>>
>>>Seems to me that the preference is Torridoidal transformers and
>>>
>>huge
>>
>>>capacity cap's, but the cap's voltage is not suposed to be lots
>>>
>>more
>>
>>>than the expected voltage of the system. is: if you plan on a 35
>>>
>>volt
>>
>>>power supply, 24 VAC trans + cap, a 50Volt cap would be good, but a
>>>100 Volt cap would actually not be a good choice.
>>>
>>>On my 12 supply from my computer, it has 500 volt cap's. it is a
>>>dual power, 220/110.
>>>
>>>Then there is the voltage increase from the steppers when not being
>>>driven, but still spinning.
>>>
>>>Is there a good rule of thumb (or actual engineering principals ?)
>>>to size a capacitor ?
>>>
>>>
>>>Dave
>>>
>>>
>>>
>>>
>>>
>>>
>>>--- In CAD_CAM_EDM_DRO@y..., scott wilson <swilson@d...> wrote:
>>>
>>>>have seen several pwr supply questions about caps....and it seems
>>>>
>>>to me that if they are being used as brute filter caps people are
>>>using way to low a working voltage....in this case i would feel
>>>
>>much
>>
>>>better with a 80-100v rating....and yes you can put them in parallel
>>>
>>>>RC wrote:
>>>>
>>>>
>>>>>Building my first power supply, needs to be approx. 42 volts @
>>>>>
>>10
>>
>>>amps.... I will need a cap with a 19,000 mf value with at least 50
>>>v. rating, the question I have is, can one "add" the mf values,
>>>instead of using one large cap? And if so, how would they be
>>>connected, series or parallel?
>>>
>>>>>Thanks,
>>>>>RC
>>>>>
>>>>>[Non-text portions of this message have been removed]
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>
> Addresses:
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>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this as a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.
>
>
>
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