Icom IC-746

IC-746 FAQ
More searching did turn up information for the SY-12-K relay, which lists a contact rating of
1 A @ 24 Vdc or 0.5 A @ 120 Vac (resistive). We can infer that the OMR-109 specs are
most likely less than these.
http://www.fceu.fujitsu.com/pdf/sy.pdf
Unfortunately, we still do not have many answers.
Contact Parts Supplers
Finally, in February 2002, we found a listing for the OMR-109F (thanks to the kind folks at
Omron Electronics for helping out). It doesn't say much, but does show a contact current
rating of 1 A.
http://catalog.tycoelectronics.com/TE/bin/TE.Connect?C=14894&P=87296,91080,8
6600,76287,76437&M=PROP&N=1&LG=1&I=81&G=G
However, the above link did show who the manufacturer is. OMR relays are made by OEG.
That finally led to some actual data sheets.
http://www.oeg.com.cn/pdf/14_OMR.pdf
http://www.qsl.net/kb9sss/IC-746/Parts/14_omr.pdf
Here are a few interesting pieces of info from the datasheet:
Max. Switched Voltage AC: 120V
DC: 60V
Max. Switched Current 1A (OMR-F)
0.5A (OMR-H).
Max. Switched Power OMR-F: 50VA, 50W.
OMR-H: 10VA, 10W
Max. Switching Rate 300 ops./min. (no load).
30 ops./min. (rated load).
Operate Time 1.0 msec
Release Time 0.5 msec
Expected Mech. Life 100 million operations (no load).
Expected Elec. Life 1 million operations (rated load)
First we see that the listed current/voltage ratings do not match anything we've seen or have
been told before. Curious that. Why has Icom technical support given out at least TWO
different sets of specs? One theory is that the relay specs we have are still not detailed
enough.
It turns out that there are two ways to report maximum contact current. "Maximum Switched
Current" is the maximum current at switching time; when the contacts are opening or closing.
Once the relay is switched on, the contact current may rise to as high as the "Maximum
Carrying Current", but must reduce again prior to switching off. Thus, if the maximum
carrying current is 2A, then the answer from Feb-2002 could make sense.
Page 45 of 113
2003-02-08