Jim Thomson wrote:
> ## Gerald, what he is implying is that when T=0.. on turn on, the
> ENTIRE 240 vac is dropped across the 1 ohm, leaving little or
> no voltage across the pri. This is how any step start works.
> Place one dvm across the main 240 input, and 2nd dvm across the
> step start R... and a 3rd dvm across the PRI. On turn on, the entire
> 240 vac is across the step start R. Zero on the PRI. A few msecs
> later, the vdrop across the pri goes up, while the V drop across the
> step start R goes down. The 2 always total 240 vac.
That is not correct. The *vector* sum of them will be 240 V, but due to the
inductance of the primary, the voltage across the primary and the voltage
across
the resistor, as measured on a DVM, do not have to sum to the supply voltage.
Of course, you need a pretty special DVM to measure the voltages with a
soft-start circuit.
Dave
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