Pilz Inc. may have what you need. They also give out free booklets on how to design "fail safe" circuits. Here is their U.S. office. They have several locations worldwide.
Pilz Inc. 24850 Drake Road Farmington Hills, Michigan 48335 (810) 473-1133 ph (810) 473-3997 fax Patty Elliot Qualcomm, Inc. [email protected] At 04:56 PM 11/6/97 +0200, Israel Yeshurun wrote: > > > Hello groupfellows. > > I am looking for a Mechanical Relay that will serve as the > disconnecting element in a "fail safe" interlock system. > > 1. This mechanical relay has to be a "Positively driven contacts > operation" or "Force guided contacts operation" - this means that if > the main contacts of the Relay are seized or welded together, than > auxiliary contacts of the relay (that are mechanically connected to > the main contacts) will also not open. Therefore, the seize or welded > situation of the main contacts can be detected through the auxiliary > contacts. (Thanks to Chris Dupres for coming up with this > information) > > In addition, the relay should also: > > 2, Have contacts rating of 230 VAC, 6 A minimum > 3. Have contacts separation of 3 mm minimum, or > 1.5 mm minimum if two main contacts are > provided and can be connected in series. > 4. Have coil rating of 24 VDC or less > 5. Have the coil separated from the contacts by at least 4 mm > spacing, 6.4 mm creepage distance. > > I have looked at a relay type G7D - 412S, by OMRON. It fulfills the > basic (item 1) and other requirements, but fails to fulfill item 3 - > it has contacts separation of less that 1.5 mm. > > If you know of Relay manufacturers that manufacture such relays, > please let me know ! > > Regards, Israel Yeshurun. Scitex Corp. > > > >
