Also, what does it mean that "it's not the voltage that kills, but the current"? Doesn't Ohm's law dictate that current is directly proportional to voltage(resistance is the same, your human body)?
Hi All! I don't know if this has been asked before, but any help appreciated.
My printrbot simple metal (upgraded to 10" X and 10" Z) recently hasn't been performing due to a heater bed problem. Every time the heater bed comes on, the printer would randomly disconnect. The heater going most likely causes an overcurrent draw from my PC powersupply. I did measure the 12V rail and it does dip. I measured the resistance of the bed and it looks to be between 0.4 to 0.7 ohms (used the minmax function of my Fluke, and subtracted lead resistance). So it certainly looks too low. Trouble is the printer and upgrade had been working very nicely for more than 3 years.
The questions I have are:
- Anyone else has this problem and solved it already? If so, do tell!
- Can anyone who has an upgraded working 10" bed measure their bed resistance to have as a reference?
- Does the resistance of the heater bed change over time? I can imagine the traces deteriorating/thinning thereby reducing its resistance, but I'm not sure if this is what's happening. If it just "became" defective, replacing with a newer better version is certainly an option.
- If the bed has deteriorated, are there any hacker sort of workaround? I've seen some online for other printers, but have not stumbled upon any for the printrbot.
Thanks in advance!
JB
TLDR: i want to regulate heater temperature via measuring heater resistance. Below is my method which sort of works. I'm open to any other methods as long as the temperature is measured via resistance and not external sensors.
I have been soldering and trying to find schematics for the better part of the day but so far no dice.
Here is the situation. I'm making a heater the temperature of which I want to keep constant.
I have worked with thermistors and thermocouples in the past but the most elegant solution would be calculating the temperature by measuring the resistance during operation and computing it from a known resistance/temperature relation.
So naively I went and made myself a shunt, calibrated it and wired it in series with my heater. Couple hours later I'm getting surprisingly accurate readings of the current, resistance and temperature. Fantastic!
Here is a high tech schematic of my circuit...
So the next step was getting a MOSFET and setting up a PID loop to adjust PWM in order to keep the temperature constant. And this is where everything failed completely. PID works fine at high duty cycles but completely shits itself at low duty cycles. Makes sense... when MOSFET is open (low duty cycle) the voltages I'm measuring go to 0 and I get fuck all useful data. This then either overshoots my DAQ, puts the PID in wild oscilations or other not so great things.
So my question to everyone is. Am I doing this completely wrong? I'm sure this can be done since consumer electronic devices do it regularly. Do I just need to change something small or is my entire methodology wrong. Ideally I'd like to know the temperature even when main current is off but just getting the temp regulation to work would be acceptable.
If it makes any difference the heater is around 0.7Ohm when cold and shunt is 3mOhm, pulling around 100W. I'm sampling at 2kHz with +-0.025mV on the shunt and around +-2mV on heater.
Out of curiosity, for folks who experienced the -10F and lower temps - what was the opinion of your heater's performance in the BEV and REx variants?
While Heatpump are much more efficient than the Resistance heaters - they usually don't work so well in really cold temperatures? Then again, being this cold a small resistance heater really isn't going to perform well either?
I'm trying to be extra careful with my TI buckets this time around and wanted to make sure they lasted.
Does anyone know what resistance these are supposed to read at?
Hi everybody I'm doing a project for the high school and my team and I want to make a kind of oven, to keep warm a piece of bread or some meal, not to cook the meal, but rather keep it warm, and I'm wondering what would be the better resistant to keep it warm in 1.5 amperes and at 7 to 9 volts approx. I'm currently using a CPU (old) and it heats up, but I want more heat, it currently uses 6 volts and 1.6 amperes, P.S. I'm going to use like 10 batteries AA
Hey guys, I'm currently a 4th year mechanical student who's just looking to make a project over the winter break. I'm trying to make a portable K cup brewer, good for one cup.
My energy and thermo skills are fine, yet I'm confused on how to apply them.
I also know nothing about electrical.
How would I go about designing a resistance heater. Let's say I need the following:
- Resistance heater heats water (1cup) from ~15c to ~80c.
- I've calculated I'll need ~2.333kw . This is the energy required to heat the water over 30s
Any resources covering designing resistance heaters I could use or follow?
How do I go about designing the actual element? What do I do about a power source? I'm looking to use a portable battery, the size of the battery should be able to fit inside of a thermos.
Using an arduino and sensors to control temp in a habitesque project but I'm sick of using this heating lamp. Its slow and wasting energy on light lol.
Im looking for a good resistance heater build; one that can be controlled by a separate power source, probably 120 volts and wont melt through any decent mount.
I'm not the best with electrical properties so any help or pointers would be appreciated.
Thanks, Poetic_Juicetice
Example from textbook: Second Law Efficiency of Resistance Heater
How does 2nd law efficiency differ from 1st law efficiency. I don't understand how 2nd law efficiency and Coefficients of Performance are related. I do understand that all the energy into the resistance heater creates heat in some form giving it 100% 1st law efficiency. Also what is exergy.
I am looking to hire a nanotech techno-optimist genius to develop/consult regarding a composite nanomaterial coating that can be deposited onto a cylindrical 24mm diameter quartz substrate or alternatively deposited onto corning's willow glass if this is not possible.
The composite coating needs to be able to heat up to an operating range of 450-600 degrees Fahrenheit, hotter than transparent resistive heaters currently offered by companies like CHASM which use a plastic substrate.
Materials I have identified as potential solutions include ag/cu nanowire, carbon nanotubes, graphene, TCO's such as FTO, and the solution will likely be a composite of these or similar materials.
I am not a nanotech person but have taken the time to familiarize myself with the typical deposition and analysis methods used in development and production and am ready to discuss the feasibility of this endeavor with an expert. The power source is preferably a lightweight lithium-ion battery.
This technology will be the basis of a profitable consumer product. Let's talk!
I have a pool heater that is about 9 years old or so. I had to replace the wire going to the igniter because the old one was in bad shape. I just used regular insulated 12 gauge stranded wire that I had laying around. Problem is that is get so hot in there that the plastic shielding is just melting off and eventually shorts out with some nearby metal.
Is there some sort of heat-resistant wire I should be using? I tried using this sort-of metal meshy sleeve thing but that was bad news as it ended up shorting out through that (if I hold this wire with my fingers while it's igniting I'll feel it).
As a side note I just cleaned out all the burners and orifices and it seems to be burning clean with no obstructions or anything, and the unit works well. I think its the high winds that, once in a while, will cause flames to go where they shouldn't and melt away the wire.
Hello
Like the title says, If I have a 450W panel and I want to convert as much of that energy into heat then how can I do it?
I was also wondering about how much power would be lost due to the impedance matching not being correct throughout the whole day. I'm guessing that I would need to custom make a heater to fit the voltage of my particular panel right?
Some advice would be appreciated.
