On Mon, 13 Dec 2004 15:58:07 -0800, put finger to
keyboard and composed:

Yes, this is a totally sealed unit with an IP rating of 67. FYI, we
mount them to the outer hub of a light rail commuter vehicle on the
center axles. I'm waiting for Deuta to respond to me with a response
to exactly the issue you pose below. The stampings on the tach lead
me to believe the 4th channel IS connected though because it is
clearly stamped "collector with R = 1k5 ch 1,2,3,4", but since I
haven't opened one up I can't say for certain.

Could the 4th channel represent some special function? For example,
could it be generating a single [hard to detect] pulse per revolution
as a timing mark? Is there any special phase relationship between the
three working channels? For example, are channels 1-3 spaced 120
degrees apart or 90 degrees, or are they in sync?


- Franc Zabkar
--
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