I am building a wood burning tool using a 2/10 amp battery charge as the power source. Should I bypass the small board containing the bridge, (12 v dc) or pickup the 12 v ac and take that to the burning tool.

As the burning element is like a direct short I would like to protect the diodes and control board.

The 115 v input is run through a fan speed control to reduce the output.
Thanks
John

 

Hello,

Waht is the nominal voltage the burning tooll needs?
You only state the 2/10 Ampere.

It is good to use a transformer to bring the voltage down.
A fan speed control direct on the mains is NOT a good idea.

Bertus

 

Thanks bertus.
The battery charger contains a transformer that is 120 V primary and 14.5 V secondary. The commercial burning tool has 10 - 12 Volts at the tip. Would it work better to bypass the bridge and bring ac to the burner tip?
John

 

In theory this might make sense, to avoid unnecessary loss in the bridge diodes. However, don't forget that you're probably dropping 2v or so across that bridge. Sending the full voltage to the tip might over-power it and burn it up. 14.5v is quite a bit more average than 11±1v.

 

That is why the fan control to reduce in coming voltage to the transformer primary. The actual inuse voltage at the burner tip may be only five volts, depends on the tip in use, the wood being burned and other variables.
John

 

Maybe this is a silly question, but why not just use a soldering iron? Unless, off course, the purpose is to build something yourself, I do that allot.

 

That is why the fan control to reduce in coming voltage to the transformer primary. The actual inuse voltage at the burner tip may be only five volts, depends on the tip in use, the wood being burned and other variables.
John

So the fan speed controller is being used to reduce power to the battery charger, and so far you've been using the normal charger output to run your iron. That all works OK, but now you're considering bypassing the charger circuitry and just using its transformer output direct to the iron. Is all that right? Sounds OK. I might have been leery of using the fan controller (as was Bertus), but if it has already been working for you and is rated for the power, it may be OK.

 

Hi. A soldering iron will not get hot enough to properly burn wood. A red hot wire is needed. If not able to keep the heat up the burner can't move at a steady speed. The ceiling fan control works great. Starts of at 2 v full open is 13 v. Great control.
I by passed the bridge and charge control board, why take a chance on screwing this up. AC on the tip is OK.
My wife thinks I am some sort of a genius and she loves her wood burner.
Thanks every one for your input. This is a great board.