4-1
Publication 700-AT001A-EN-E June 2002
Chapter
4
Q & A
What Is The Zero
Cross Function?
The zero cross function turns ON the SSR when the AC load voltage is
close to 0 V, thus suppressing the noise generation of the load when
the load current rises quickly.
The generated electrical noise will be partly imposed on the power line
and the rest will be released in the air. The zero cross function
effectively reduces/suppresses both noise paths.
A high inrush current will flow when the load is turned ON. When the
zero cross function is used, the load current always starts from a point
close to 0 V. This will reduce/suppress the inrush current more than
SSRs without the zero cross function.
It is ideal for the load current to start from 0 V when the zero cross
function is used. Due to circuit restrictions, however, the load current
will start from a point that is 0 ± 20 V. The difference in voltage between
this point and the 0 V point is called zero cross voltage.
ON
ON
ON
ON
OFF
ON
OFF
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