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:[email protected]] Sent: Thursday, December 7, 2017 12:29 PM To: [email protected] 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 <[email protected] <mailto:[email protected]> > 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) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected] <mailto:[email protected]> > Mike Cantwell <[email protected] <mailto:[email protected]> > For policy questions, send mail to: Jim Bacher <[email protected] <mailto:[email protected]> > David Heald <[email protected] <mailto:[email protected]> > - ---------------------------------------------------------------- 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
