VARIAC....MEX?
Hopefully MEX will chime in but anyone else is welcome, of course. Looking to buy a VARIAC. I have a Harbor Freight manual charger that I use for equalizing and sometimes the finishing charge. The pro...
Forum Discussion
mena661 wrote:
I'm definitely missing something here. So I should raise voltage slowly then connect the load??
mena661, a Variac is really nothing more than a specialized autotransformer.
The primary voltage is applied to a set of fixed transformer windings that produces a constant volt/turn value.
The variable voltage output connection is made via a set of wiper contacts that selects groupings of windings to produce the variable output voltage.
These wiper contacts will have no current flowing through them if a load is not connected which is ideal.
When a load is connected, current flows through contacts which is typically not an issue if the contacts stationary as long as an overload condition doesn't exist.
However, moving the wiper contacts while loaded can cause arcing which will increase wear and cause increased contact resistance and possible premature failure.
So set the voltage first and then load the transformer for best life.
