Humming on my variac
furnace, Sun Oct 13 2013, 10:29PMHi everyone!
I've build an induction heater based on mindchallenger schematic. Everything works perfect and my mosfets are staying very cool. The only problem is that on high power levels my variac starts to humm allot. At this level my variac is on 75 volts and my tank is pushing 300volts, I don't know what the amps is because I don't have clamp metre. My 3 toroids are turned 5 on primary to 1. If anyone can give some advise it would really help.
Thanks.
Re: Humming on my variac
Steve Conner, Mon Oct 14 2013, 08:38AM
Here's some advice, buy an ammeter!
Steve Conner, Mon Oct 14 2013, 08:38AM
Here's some advice, buy an ammeter!
Re: Humming on my variac
klugesmith, Mon Nov 11 2013, 02:54AM
Furnace:
As Steve Connor implied, it's silly to be building induction heaters
with no way to measure their input current.
There are several easy, inexpensive wasy to measure AC current
without using a clamp meter or a fancy multimeter.
If you put (or build) your AC ammeter on one wire of an extension cord or power strip,
then you can measure current without modifying the apparatus under test.
You can start by measuring desk lamps and toasters, then plug in your IH's variac.
Category 1. Get an analog or digital panel meter that indicates AC amperes.
Or an analog or digital panel meter that indicates DC amperes, and a bridge rectifier.
Category 2. Wire in your own current shunt resistor, and measure the voltage drop.
Do you have one or more regular multimeters (digital or analog)?
What are the lowest AC voltage and DC voltage ranges?
What's your desired AC current range?
That'll be our starting point (no time now to write a universal FAQ).
klugesmith, Mon Nov 11 2013, 02:54AM
Furnace:
As Steve Connor implied, it's silly to be building induction heaters
with no way to measure their input current.
There are several easy, inexpensive wasy to measure AC current
without using a clamp meter or a fancy multimeter.
If you put (or build) your AC ammeter on one wire of an extension cord or power strip,
then you can measure current without modifying the apparatus under test.
You can start by measuring desk lamps and toasters, then plug in your IH's variac.
Category 1. Get an analog or digital panel meter that indicates AC amperes.
Or an analog or digital panel meter that indicates DC amperes, and a bridge rectifier.
Category 2. Wire in your own current shunt resistor, and measure the voltage drop.
Do you have one or more regular multimeters (digital or analog)?
What are the lowest AC voltage and DC voltage ranges?
What's your desired AC current range?
That'll be our starting point (no time now to write a universal FAQ).
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