Diode in series with the mains

I use a variac with an AC ammeter in line. I like to heat test kit using a hot air gun on low setting. But for the low heat range, a diode is in series with the mains, the one-sided "switching" 50/60 times a second causes horrendous magnetising current problems that would overheat the variac I'm sure, used on the same mains ring main. Replace that diode with a preset triac for balanced "switching" ? I one time niaively thought putting a 1N4007 in series with a 50W, 24V soldering iron Tx would give a low temperature iron for melting plastic, ended up melting the 24V Tx. What effect , if any , would such diodes in say hot air guns, falsely? register on a moving disc mains kWh meter or the recent "smart" meters / monitors ?

Reply to
N_Cook
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** On the output side?

** You are exaggerating a bit.
**Could be a gotcha there - how does the fan get its power?

In my old Black & Decker (Made in England) 1600 watt gun, the DC fan runs via one diode from a tap on the main heater winding. The half power diode has the same wiring polarity so fan operation is not stopped at half setting.

Fit a triac and the fan would lose half its power, so the air would be just as hot with either setting.

** Suspect half wave loads make them under read a bit.

Why not try it out while counting turns on the big wheel

.... Phil

Reply to
Phil Allison

Diodes I ever seen are always on the secondary side of the transformer.

Reply to
hrhofmann

** Everyone is MISSING the point here.

The *diode* in question is INSIDE the hot air gun !!

Using it produces an ASSYMETRICAL load on the AC supply.

That in turn produces a small DC OFFSET in the supply - maybe 0.5 to 1 volt.

THAT in turn causes partial core saturation, particularly with TORROIDAL transformers, on the same supply circuit.

When did a toroidal come into the picture ?

WTF do you think a Variac is??

FYI"

The Nutcase Kook Troll **NEVER** explains anything he posts.

.... Phil

Reply to
Phil Allison

Not directly relevant to this discussion, but I am reminded of this story. Perhaps you'll like it:

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Reply to
Chris Jones

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