Re: [PSES] Pilot rating

2017-12-08 Thread Peter Tarver 
Hi, Jon.

Switching a contactor or relay coil does involve an inrush current and 
inductive kickback, as previously mentioned. This can affect air gap contacts 
in significant ways.

For solid state switching, I’m less familiar with the ins and outs, but if you 
look at some SSR manufacturers’ web sites, you can see that there are different 
P/Ns within a family of SSRs, depending on the nature of the switched load. For 
example, use

http://www.crydom.com/en/tools/parametric-search.shtml?type=panel

to go through some examples.

Also, check out (not very detailed, but it gives a flavor)

http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE=1=LatestReleased=0=Primary=AP04901001E

There are bound to be some snubbing features built into these SSRs, just as 
there would be for an electromechanical relay.

A lot of SSRs are zero crossing types to prevent switching on higher voltages. 
This can prolong the life of the SSR.

It could simply be clever marketing to change a P/N, but it might also be that 
there’s a physical difference in the SSRs that make them better suited to 
certain types of loads.

It may be that your design satisfies all of the necessaries for piloting a 
contactor of a certain VA rating. An NRTL will likely want to do some testing 
to satisfy themselves that the special concerns are met by your design. If your 
company is not planning to sell the solid state switch, you can probably 
negotiate a reduced test program based on your application. If you do 
negotiate, make sure you build in some head room for load changes so you don’t 
have to repeat testing when someone gets a clever idea for how to repurpose 
your design.


Regards,

Peter Tarver

From: Richard Nute [mailto:ri...@ieee.org]
Sent: Friday, December 08, 2017 13:09
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Pilot rating


The ultimate issue is what safety issue occurs if the contactor fails to open 
or close when it is supposed to?  If there is no safety consequence, then the 
contactor control is functional, not a safeguard.  If there is a safety 
consequence, then the circuits controlling the contactor constitute a safeguard 
and must be “reliable,”  and must meet the intent of the standard.

Not so cynical Rich


From: Jon Keeble [mailto:j...@wattwatchers.com.au]
Sent: Thursday, December 7, 2017 12:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Pilot rating

I am using a Panasonic AQH3213A PhotoMOS optical isolator to control a small 
contactor.

At 110VAC the contactor coil draws 30mArms.
The coil contacts are wired to a PCB via a terminal block plug and socket.

On the PCB is a series 10ohm fusible resistor, and a SMBJ400AC bidirectional 
zener.

When the switch opens at peak current (42mA) there is 0.1J of energy in the 
coil that gets absorbed by the zener.

The zener
* clamps at a voltage way below the voltage rating of the optoMOS switch.
* is rated at 600W for 8.3msec and is subject to only 13W for a similar period.

The UL test engineer says that the optoMOS should be "pilot duty" rated (the 
part I am using does have this rating).

Does anyone know what triggers the requirement for a "pilot duty" rating?
Is this defined in a standard somewhere?

This useful link identifies "contact rating codes"
https://na.industrial.panasonic.com/blog/what-pilot-duty-rating-how-it-obtained

The lowest rating E300 is for 110V 1.8A (make) 0.3A (break)

Technically speaking, my switch is not connected to the contactor .. there is a 
two-component network in between
Does UL have the capacity or procedures in place to understand and accept a 
circtuit analysis that shows my circuit as safe?

Jon Keeble

Wattwatchers.



-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
>

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to 
unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas >
Mike Cantwell >

For policy questions, send mail to:
Jim Bacher >
David Heald >
-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to

Re: [PSES] Pilot rating

2017-12-08 Thread Richard Nute 
 

The ultimate issue is what safety issue occurs if the contactor fails to open 
or close when it is supposed to?  If there is no safety consequence, then the 
contactor control is functional, not a safeguard.  If there is a safety 
consequence, then the circuits controlling the contactor constitute a safeguard 
and must be “reliable,”  and must meet the intent of the standard.

 

Not so cynical Rich

 

 

From: Jon Keeble [mailto:j...@wattwatchers.com.au] 
Sent: Thursday, December 7, 2017 12:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Pilot rating

 

I am using a Panasonic AQH3213A PhotoMOS optical isolator to control a small 
contactor.

 

At 110VAC the contactor coil draws 30mArms.

The coil contacts are wired to a PCB via a terminal block plug and socket.

 

On the PCB is a series 10ohm fusible resistor, and a SMBJ400AC bidirectional 
zener.

 

When the switch opens at peak current (42mA) there is 0.1J of energy in the 
coil that gets absorbed by the zener.

 

The zener 

* clamps at a voltage way below the voltage rating of the optoMOS switch.

* is rated at 600W for 8.3msec and is subject to only 13W for a similar period.

 

The UL test engineer says that the optoMOS should be "pilot duty" rated (the 
part I am using does have this rating).

 

Does anyone know what triggers the requirement for a "pilot duty" rating?

Is this defined in a standard somewhere?

 

This useful link identifies "contact rating codes"

https://na.industrial.panasonic.com/blog/what-pilot-duty-rating-how-it-obtained

 

The lowest rating E300 is for 110V 1.8A (make) 0.3A (break)

 

Technically speaking, my switch is not connected to the contactor .. there is a 
two-component network in between

Does UL have the capacity or procedures in place to understand and accept a 
circtuit analysis that shows my circuit as safe?

 

Jon Keeble

 

Wattwatchers.

 

 

 

-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
 >

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 
 
List rules: http://www.ieee-pses.org/listrules.html 

For help, send mail to the list administrators:
Scott Douglas  >
Mike Cantwell  > 

For policy questions, send mail to:
Jim Bacher  >
David Heald  > 


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald:

Re: [PSES] Cable current clamp with 4-20mA output

2017-12-08 Thread Rob Oglesbee 
What accuracy class?  If this is for sub-metering, something like this probably 
won’t work, but it does meet the cheap requirement:

https://www.olimex.com/Products/Components/Sensors/SNS-CURRENT-CT013-100A/

If you need something more accurate, AEMC has a wide selection of probes, but 
they start at an order of magnitude more expensive:

http://store.aemc.com/AC-Current-Probe-Model-MN01_p_585.html

Regards,
Rob


From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Friday, December 08, 2017 1:58 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Cable current clamp with 4-20mA output

I’m looking for a low cost cable current clamp for 50/60Hz current measurements 
and with 4-20mA output. Snap-on mechanism is a must.
It should be a really «low cost» device, since the numbers of clamps in a large 
building can be 10++, maybe 100.

Any recommendations?

Best regards
Amund







-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
>

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to 
unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas >
Mike Cantwell >

For policy questions, send mail to:
Jim Bacher >
David Heald >

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald:

Re: [PSES] Pilot rating

2017-12-08 Thread Richard Nute 
 

 

“Agreement is usually a compromise for both sides.”

 

Unfortunately, the process denigrates science and engineering (but saves face 
for both sides, especially the certification house).

 

Still cynical Rich

 

 


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: