...@tamuracorp.com]
Sent: Monday, March 30, 2015 1:56 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NEC vs CEC for Transformer Protection
5085-3/CSA No66.3 scoped only where class 2 or 3 stuff is required, and
generally not considered for industrial environment where the secondary circuit
not exposed
In message
64D32EE8B9CBDD44963ACB076A5F6ABB026D7789@Mailbox-Tech.lecotech.local,
dated Wed, 1 Apr 2015, Kunde, Brian brian_ku...@lecotc.com writes:
It would seem our only option is to add overcurrent protection to the
secondary side of the transformer so we can size the Primary OPD so not
to
side impedance can
also play a part in the play.
Regards,
Bob
N9NEO
-Original Message-
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Sunday, March 29, 2015 11:59 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NEC vs CEC for Transformer Protection
In message b3cae477
In message
2313bb439627e348a579b7b3f41d9c143d364...@newcastle.creare.com, dated
Mon, 30 Mar 2015, Bob LaFrance b...@creare.com writes:
Inrush current is a function of source voltage as well as transformer
characteristics as previously mentioned in thread.
Naturally.
Input side impedance
-- Original Message --
From: Nyffenegger, Dave dave.nyffeneg...@bhemail.com
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NEC vs CEC for Transformer Protection
Date: Sun, 29 Mar 2015 16:03:28 +
Engineers doing any sort of direct public work in the U.S. must be licensed
to this
discussion.
Brian
From: Brian Gregory [mailto:brian_greg...@netzero.net]
Sent: Monday, March 30, 2015 10:03 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NEC vs CEC for Transformer Protection
I'd restate Dave's case below to say: PE's are really only required for Public
Sector work
John,
I can’t disagree with any of your statements, only say that this is what is
commonly done in practice. Many machine builders have people doing design work
who have only minimal qualifications - 2 yr technician diplomas, or people that
have “learned by doing”. It depends on the company
. The same
industrial exception exists in the US and this does carry through to products
for sale.
-Dave
-Original Message-
From: Mr. Doug Nix C.E.T. [mailto:d...@ieee.org]
Sent: Sunday, March 29, 2015 11:40 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NEC vs CEC for Transformer
In message b3cae477-8211-419c-8dc7-b3df60f37...@ieee.org, dated Sun,
29 Mar 2015, Mr. Doug Nix C.E.T. d...@ieee.org writes:
I can’t disagree with any of your statements, only say that this is
what is commonly done in practice. Many machine builders have people
doing design work who have only
Typically, designers in Canada use two general rules for guidance in protecting
transformers, with little actual calculation of inrush currents considered:
1) If no secondary OCD is provided, then the primary OCD will be selected at
125% of rated full load current, if inrush proves a problem,
In message 9dd08e56-75ed-4ae5-a80a-26a08324b...@ieee.org, dated Sun,
29 Mar 2015, Mr. Doug Nix C.E.T. d...@ieee.org writes:
Typically, designers in Canada use two general rules for guidance in
protecting transformers, with little actual calculation of inrush
currents considered:
1) If no
In message
blupr02mb1162ba09cc137bdb35ca50ac1...@blupr02mb116.namprd02.prod.outlook
.com, dated Sun, 29 Mar 2015, Brian Oconnell oconne...@tamuracorp.com
writes:
nrush peak for 50/60Hz transformers mostly from magnetizing current -
core saturation and residual flux, and of course input V. As
Inrush peak for 50/60Hz transformers mostly from magnetizing current - core
saturation and residual flux, and of course input V. As the saturation curve
does not extend past the pi/2 inrush peak, any further inrush past a few mSec
is typically from filling up the coulomb buckets on the
@LISTSERV.IEEE.ORG
Subject: [PSES] NEC vs CEC for Transformer
Protection
Please help.
We have a product, laboratory equipment, that has
a 330 watt 1:1 230Vac isolation transformer. 330w
/ 230V = 1.34 amps.
To protect this transformer we applied the US-NEC
table 450.3(B) to where the primary protector can
...@ieee.org]
Sent: Saturday, March 28, 2015 9:58 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] NEC vs CEC for Transformer Protection
Hi Brian:
I can't help you with the CEC.
Both the NEC and CEC are quite wrong to specify overcurrent protection as a
function of rated input current.
Overcurrent
In message 000201d06978$5f687e60$1e397b20$@ieee.org, dated Sat, 28 Mar
2015, Richard Nute ri...@ieee.org writes:
Thermally-caused insulation failure can be controlled by a fuse in the
primary. Load the secondary and measure the insulation temperature.
I think you have to reduce the load
Please help.
We have a product, laboratory equipment, that has a 330 watt 1:1 230Vac
isolation transformer. 330w / 230V = 1.34 amps.
To protect this transformer we applied the US-NEC table 450.3(B) to where the
primary protector can be up to 300% of the of 1.34 amps. The transformer
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