Hello Roger: For telecom transformers, these are some relevant dielectric (50Hz or 60Hz) withstand tests that I am aware of:
>From FCC part 68.304 "Leakage Current Limitations": the telecom connection >has a number of 1000 V dielectric tests (table 68.304a) in which the telecom >transformer is providing the isolation. UL1459 also specifies similar 1000V tests in table 58.2 and figure 58.1. These are one minute tests. UL 1459 section 72 (see table 72.1) allows for a one second 1200VAC test (in production) in place of a 60 second 1000VAC test (I think CSA 225 does also). This is probably why you see 1000 to 1200V ratings on these transformers. The above is my own, to the best of my knowledge, and not necessarily the opinion of Midcom. Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 e-mail: [email protected] Fax: (605) 886-6752 ---------- From: Roger Prenger[SMTP:[email protected]] Sent: Monday, November 18, 1996 6:05 PM To: [email protected] Cc: [email protected] Subject: Part 68 and PCMCIA Voltages Hey all, Last time I worked with a PCMCIA Card, I thought the transformers on the card had to be rated at about 2700 Volts. I am now looking at some new PCMCIA cards and it appears they are coming out with transformers rated at 1000-1200 Volts. Has Part 68 been changed or are these cards out of spec? advTHANKSance, roger [email protected] "Life's but a walking shadow; a poor player, That struts and frets his hour upon the stage, And then is heard no more: it is a tale Told by an idiot, full of sound and fury, Signifying nothing." - MacBeth, 'MacBeth', William Shakespeare
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