We want to use a small air pump, about the size of an aquarium pump, in one of our products (laboratory equipment). It has a small 24Vdc brushed motor without any visible safety certification markings.
In these cases, we usually perform the locked rotor test according to IEC/UL/EN 61010-1 section 14.2. However, when we attempted this test the motor got hot very quickly and then failed open circuit before we could get a stable winding temperature reading. Max. temperature read was about 120ºC at 40ºC ambient. This motor has Class F insulation which can handle 190ºC in a fault condition, but like I said the motor failed before we could reach a stable temperature. If the winding overheated and melted open, would this be considered a fire hazard? Or because something in the motor failed before the winding temperature reached 190ºC that this motor can be considered inherently safe? The pump manufacturer is telling us the motor is UL Recognized even though the marking does not appear on the motor. If this motor is UL Rec. can I assume it would pass the locked rotor test? I have heard in the past that UL certified motors are not always tested for locked rotor. Is this true? If you were me, what criteria would you require for use of such a motor in your product? Thank you in advance. The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
