Re: [PSES] Votlage Rating vs Voltage Specificaion

[Doug Powell]

  Unfortunately this was a consulting job and the arrangements had already been made by the company in question.  I was there to help them through the findings of the PDR. Doug   From: ri...@ieee.orgSent: April 6, 2017 11:46 AMTo: EMC-PSTC@LISTSERV.IEEE.ORGReply-to: ri...@ieee.orgSubject: Re: [PSES] Votlage Rating vs Voltage Specificaion   “As a result the agency engineer wanted to apply the ±10% rule to the rating label voltage…” Never submit a product to a certification house that you have not tested and evaluated for all the requirements.  You should not have any failures at the certification house (and the certification will be complete on the promise date).  Keep a running list of all your submittals and the deficiencies.  The list will be useful in your performance review or, if consulting, in building client confidence.  Easy to do with the CB report form (which you can submit with the product and will bias the cert house to your way of interpreting the requirements as applied to your product).   Rich 
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Re: [PSES] Votlage Rating vs Voltage Specificaion

[Richard Nute]

 

“As a result the agency engineer wanted to apply the ±10% rule to the rating 
label voltage…”

 

Never submit a product to a certification house that you have not tested and 
evaluated for all the requirements.  You should not have any failures at the 
certification house (and the certification will be complete on the promise 
date).  Keep a running list of all your submittals and the deficiencies.  The 
list will be useful in your performance review or, if consulting, in building 
client confidence.  Easy to do with the CB report form (which you can submit 
with the product and will bias the cert house to your way of interpreting the 
requirements as applied to your product).  

 

Rich

 

 

 

 

 


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Re: [PSES] Votlage Rating vs Voltage Specificaion

[Richard Nute]

 

 

Hi Doug:

 

“…had a design engineer who took those numbers from the datasheet and 
transcribed them directly to the rating label of his product.”

 

This is the problem:  The safety guy didn’t do his job!  (I presume it wasn’t 
you!)

 

I prefer nominal input voltage rating numbers, not ranges.  The nominal number 
is used for the + and – 10% calculation.  The rating is not normally used by 
the customer unless he is moving the unit from one country to another.  Plug 
configuration sets the rating regardless of the label. So, the rating is mostly 
used by the certification house to maximize the safety performance of the unit. 
 

 

Extreme input voltages are likely to break the power supply, but unlikely to 
cause a safety deficiency.  

 

Best regards,

Rich

 

 


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Re: [PSES] Votlage Rating vs Voltage Specificaion

[John Woodgate]

There is a vocabulary issue here. The IEC defines 'rated' as [simplified] 'the 
value stated by the manufacturer'. So for the PSU manufacturer, 85 V and 264 V 
are indeed 'rated' values. But of course you are right; the product should have 
rated values of [probably] 100 V to 240 V. It's got to be part of the training 
of the design engineer.
 
With best wishes DESIGN IT IN! OOO – Own Opinions Only
 <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and 
Associates Rayleigh England
 
Sylvae in aeternum manent.
 
From: Doug Powell [mailto:doug...@gmail.com] 
Sent: Wednesday, April 5, 2017 11:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Votlage Rating vs Voltage Specificaion
 
Hi all,
 
Has anyone found a good way to explain to non-compliance types the difference 
between voltage rating and voltage specification?  After all these years I 
still run into this discussion and have not found a good way to clear the air.
 
A classic example is an open frame AC/DC power supply used to produce the 
housekeeping voltages within a larger product.  In a recent example, the PSU 
datasheet stated the voltage input range as 85 to 264 VAC.  This is great and I 
really like that specification. However, I also had a design engineer who took 
those numbers from the datasheet and transcribed them directly to the rating 
label of his product.  As a result the agency engineer wanted to apply the ±10% 
rule to the rating label voltage and the rating tests were then 76.5 to 290.4 
VAC (this was not an ITE product).  Note: a little quick math shows that the 
264 VAC upper limit of the PSU is actually a result of 240 V plus 10%. 
 
All this seems obvious to me but apparently not to everyone ... and maybe it's 
me who is just a few sandwiches short of a picnic.
 
I would be grateful to hear any experiences where explanations were successful 
and lasting.
 
 
-- 
 
Douglas E Powell

doug...@gmail.com <mailto:doug...@gmail.com> 
http://www.linkedin.com/in/dougp01
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Re: [PSES] Votlage Rating vs Voltage Specificaion

[Doug Powell]

  Bostjan,Thank you, I am also familiar with Working Voltage.  And I sometimes add 'long term working voltage'.  On occasion, some engineers have attempted to use the isolation voltage of a component as the voltage rating. Most often the isolation voltage is the 60 second dielectric test voltage.  And so, on it goes...All my best,  DougFrom: bostjan.gla...@siq.siSent: April 5, 2017 6:08 PMTo: doug...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORGSubject: RE: [PSES] Votlage Rating vs Voltage Specificaion  







Hi Doug,
 
I am familiar with expressions: operational voltage range  and rated voltage range. Operational voltage range is in fact
 rated voltage range with tolerances. In your case 85-264V is operational voltage range, while unit is rated 100-240V. tolerances on rated voltages in your case are -15%/+10%.
 
I hope this helps a bit.
 
Best regards,
Bostjan
 
 
 
From: Doug Powell [mailto:doug...@gmail.com]

Sent: Thursday, April 6, 2017 12:52 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Votlage Rating vs Voltage Specificaion
 


Hi all,


 


Has anyone found a good way to explain to non-compliance types the difference between voltage rating and voltage specification?  After all these years I still run into this discussion and have not found a good way to clear the air.


 


A classic example is an open frame AC/DC power supply used to produce the housekeeping voltages within a larger product.  In a recent example, the PSU datasheet stated the voltage input range as 85 to 264 VAC.  This is great and I really
 like that specification. However, I also had a design engineer who took those numbers from the datasheet and transcribed them directly to the rating label of his product.  As a result the agency engineer wanted to apply the
±10% rule to the rating label voltage and the rating tests were then 76.5 to 290.4 VAC (this was not an ITE product).  Note: a little quick math shows that the 264 VAC upper limit of the
 PSU is actually a result of 240 V plus 10%. 


 


All this seems obvious to me but apparently not to everyone ... and maybe it's me who is just a few sandwiches short of a picnic.


 


I would be grateful to hear any experiences where explanations were successful and lasting.


 


 

-- 





 

Douglas E Powell

doug...@gmail.com
http://www.linkedin.com/in/dougp01





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Re: [PSES] Votlage Rating vs Voltage Specificaion

[Boštjan Glavič]

Hi Doug,

I am familiar with expressions: operational voltage range  and rated voltage 
range. Operational voltage range is in fact rated voltage range with 
tolerances. In your case 85-264V is operational voltage range, while unit is 
rated 100-240V. tolerances on rated voltages in your case are -15%/+10%.

I hope this helps a bit.

Best regards,
Bostjan



From: Doug Powell [mailto:doug...@gmail.com]
Sent: Thursday, April 6, 2017 12:52 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Votlage Rating vs Voltage Specificaion

Hi all,

Has anyone found a good way to explain to non-compliance types the difference 
between voltage rating and voltage specification?  After all these years I 
still run into this discussion and have not found a good way to clear the air.

A classic example is an open frame AC/DC power supply used to produce the 
housekeeping voltages within a larger product.  In a recent example, the PSU 
datasheet stated the voltage input range as 85 to 264 VAC.  This is great and I 
really like that specification. However, I also had a design engineer who took 
those numbers from the datasheet and transcribed them directly to the rating 
label of his product.  As a result the agency engineer wanted to apply the ±10% 
rule to the rating label voltage and the rating tests were then 76.5 to 290.4 
VAC (this was not an ITE product).  Note: a little quick math shows that the 
264 VAC upper limit of the PSU is actually a result of 240 V plus 10%.

All this seems obvious to me but apparently not to everyone ... and maybe it's 
me who is just a few sandwiches short of a picnic.

I would be grateful to hear any experiences where explanations were successful 
and lasting.


--

Douglas E Powell

doug...@gmail.com<mailto:doug...@gmail.com>
http://www.linkedin.com/in/dougp01
-


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[PSES] Votlage Rating vs Voltage Specificaion

[Doug Powell]

Hi all,

Has anyone found a good way to explain to non-compliance types the
difference between voltage rating and voltage specification?  After all
these years I still run into this discussion and have not found a good way
to clear the air.

A classic example is an open frame AC/DC power supply used to produce the
housekeeping voltages within a larger product.  In a recent example, the
PSU datasheet stated the voltage input range as 85 to 264 VAC.  This is
great and I really like that specification. However, I also had a design
engineer who took those numbers from the datasheet and transcribed them
directly to the rating label of his product.  As a result the agency
engineer wanted to apply the ±10% rule to the rating label voltage and the
rating tests were then 76.5 to 290.4 VAC (this was not an ITE product).
Note: a little quick math shows that the 264 VAC upper limit of the PSU is
actually a result of 240 V plus 10%.

All this seems obvious to me but apparently not to everyone ... and maybe
it's me who is just a few sandwiches short of a picnic.

I would be grateful to hear any experiences where explanations were
successful and lasting.


-- 

Douglas E Powell

doug...@gmail.com
http://www.linkedin.com/in/dougp01

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