SoliForum - 3D Printing Community — Nichrome Ohms and Heat

Re: Nichrome Ohms and Heat

null@example.com (caswal) — Mon, 31 Dec 2012 01:05:32 +0000

If you want to read about electronics, this website is fantastic http://www.electronics-tutorials.ws/.

Ohm's law states that:
Current (I) = Voltage (V) / Resistance (R) (Equation is I = V/R)
The result is in amps

So, the stock SD heater is:
12v / 3ohms = 4 amps.

Power (Watts) = Voltage (V) x Current (Amps)
So the stock heater is 48 watts.

With your nichrome wire setup (that I also plan on replicating)
12v / 3.4 ohms = 3.5amps

12v x 3.5 amps = 42 watts. Which is 12.5% less powerful than stock, so it would be noticeable (my rule of thumb, is you need a 10% change before people/you notice the difference).

Re: Nichrome Ohms and Heat

null@example.com (elmoret) — Mon, 31 Dec 2012 00:21:01 +0000

Less ohms allows more current to flow, which makes more heat. Air has a near infinite resistance, and your wall outlets don't get hot.

It's questionable whether the solidoodle hardware can handle the 3 ohm load. Definitely don't increase the current (decrease the ohms) unless you also upgrade the power supply and reinforce the PCB traces.

Nichrome Ohms and Heat

null@example.com (perlguy) — Sun, 30 Dec 2012 22:07:12 +0000

I am not an electrician, nor have I ever played one on TV...

I was wondering. With the glass-bed modification, it was mentioned that you needed to end up with 3 Ohms of resistance when all of your nichrome wire was squiggled throughout the bottom of the glass.

I am coming in at about 3.4 Ohms, and I am having issues getting the glass hot enough.

My questions are:

* Would more (or less) ohms create more heat?
* How many ohms can the solidoodle hardware handle? (given that it was originally a 3 Ohm resister)

Thanks!