One other point. Make sure you know what current you're handling. 8 a
and 120 Vac is 960 VA drop that to 30 Vdc and the equipment still needs
the power delivered but now your're talking 32 amps. Just an example but
it makes a point.
Gary
-----Original Message-----
From: Robert Johnson [SMTP:robe...@ma.ultranet.com]
Sent: Monday, November 02, 1998 7:01 AM
To: Stewart, Judd
Cc: 'EMC-PST'
Subject: Re: IEC 320 APPLIANCE COUPLER APPLICATION
There are two concerns about the (mis)use of the connector you
discussed. I
assume you are talking about the IEC 320 C13 (female, 10A, 70C)
and C14 (male),
although it probably doesn't matter which IEC 320 connectors you
are talking
about. Note that there are some 22 different connectors
currently and probably
more to come. The very first sentence of the IEC 320 standard
states that these
are for ac only.
The first concern is the consequence of plugging a cord into
your product which
carries (up to) 250 Vac into your 24 volt input. You must assure
that should
this happen, the product will remain safe (not necessarily still
functioning,
but safe).
The second concern is the consequence of plugging your 24 volt
source into a
product expecting 120 or 240 Vac. This is a tough one since you
don't know the
product. It could be a transformer load, in which case you would
be likely to
overheat and burn out the winding. If you can figure out the
consequences of
this for all products you are a much better engineer than I.
The consequence is that your design is pretty likely to be
unsafe under
conditions of forseeable misuse, and is in violation of
standards in those
countries which have adopted the use of IEC standards. I
recommend you try
something else.
Keep in mind it may be reasonable to come up with a hybrid
connector useful for
combined ac/dc use. For example it is reasonable to have a
product which can
operate on 40-250 V ac/dc. Such a device would work on 48 Vdc
central office
supplies as well as typical ac supplies. A modified IEC 320 C13
connector with
projections to prevent its use in a normal C14 connector could
carry dc into
such a product and still meet the above two concerns, while
allowing the product
to accept normal ac cordsets as well. It also solves the problem
of having to
guard live unused connections intended for the alternate supply
source.
"Stewart, Judd" wrote:
> Good afternoon everyone,
>
> Problem-
>
> A universal battery charger that I am reviewing is powered by
AC 110-220 or
> 24VDC.
>
> The 24 VDC enters the device via a male IEC 320
connector....OUCH!.
>
> The AC enters via a non-detachable recognized power cord with
NEMA- 5-15
> molded male connector.
>
> Commons sense would tell you not to use this connector for the
DC but they
> did...The likely hood that someone would plug AC into it is
extremely high.
> I am looking for a regulation/standard to reference that would
prevent this
> sort of application...
>
> any Ideas?
>
> Thanks in advance,
>
> Judd Stewart
> 619.623.6639
>
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