[quote=“KLucky13”][quote=“2stimpy”]It is a nice little switch.
Power from the external supply to the in side, connect the heatbed on the out side.
The little 2 pins are for the signal from the controller. That would be the the wires that are now connected to your heatbed.
I contacted them and they told me the fet used on the print would be capable to handle up to 30v and 76 amps
I am using the 100 w 24 volt, and it reaches 100c in about 20 to 25 minutes.
It can handle the heatbed without any problem. The wiring does not need to be upgraded for this.
But keep in mind that if you want to use another heatbed like me, you will have to change to another power supply again.
I hate to wait that long, and want to be able to reach the 110 degrees.
I don’t know if the 320 will be enough for an upgraded be, but i doubt it.
[quote=“2stimpy”]I am using the 100 w 24 volt, and it reaches 100c in about 20 to 25 minutes.
It can handle the heatbed without any problem. The wiring does not need to be upgraded for this.
But keep in mind that if you want to use another heatbed like me, you will have to change to another power supply again.
I hate to wait that long, and want to be able to reach the 110 degrees.
I don’t know if the 320 will be enough for an upgraded be, but i doubt it.[/quote]
I have the 320 W supply and a Mk3B Alu heat bed (which I haven’t installed yet). I plan on running on the 12 V terminals with 24 V, which should drain about 4-500 W. This will thus max the power supply out, but it will probably be more than enough to heat up extremely quickly. (320 W compared to approximately 120 W on the stock bed, which however already allows me to reach 115 C on my chambered printer.)
[quote=“2stimpy”]I am using the 100 w 24 volt, and it reaches 100c in about 20 to 25 minutes.
It can handle the heatbed without any problem. The wiring does not need to be upgraded for this.
But keep in mind that if you want to use another heatbed like me, you will have to change to another power supply again.
I hate to wait that long, and want to be able to reach the 110 degrees.
I don’t know if the 320 will be enough for an upgraded be, but i doubt it.[/quote]
Wow, 20-25 minutes? That’s indeed extremely long… Is there any way to heat up the standard bed faster then that? With the 340 watt supply for example?
running the original heatbed on 24 V gives you around 80 W of heating power at 80 to 90 °C. Around, because the actual value depends on the resistance, could be only 75 W for some beds, or also 85 or even 90 W for others. At low temperatures, the heating power is higher, since the resistance of the copper increases with temperature. In a setup with free airflow, 80 W is enough for about 75 degrees above room temperature, i.e. between 90 and 100 °C. If your bed is above the 80 W (or the room very hot, or the airflow restricted in a chamber), you can surpass 100 °C, like magu has.
In order to further increase the heating power of the original PCB, you would have to use even higher voltages. A fixed 24 V power supply cannot do this, no matter how much current and power it can deliver. So, from that point of view, it doesn’t matter whether you chose the 100 W or the 320 W version of the supply (by the way, there are two types with ca. 150 W, too). If you want to install a different 24 V-capable heatbed with more than 100 W heating power later on, of course a larger supply would be better.
About the wires: rule of thumb for isolated wires (with not so thick isolation) is 10 A per mm² cross section. The quadrupled ribbon cable should be around 0.5 mm² (is it 0.14 each?), so if you go above 5 A, you need to install different wires. Note that the maximum current is the one at room temperature, not at operating temperature. For example: my bed uses ca. 4.3 A at RT, but only 3.7 A at 50 °C and 3.3 A at 90 °C.
magu, if you max out the power supply, don’t you risk overheating and shutting down the psu?
If it cools down it will probably work again but you risk ruining your print.
Thanks for the info kuraasu, I’ll think about it what supply to buy. I’ll probably look into other heat-beds as wel… What did you do to be able to print at with a bed @ 100 °C (for ABS printing)? What supply/heatbed combination?
So if I understood your explanation wel, speeding up the heat up proces to reach 100 degrees can only be achieved with an other heatbed with higher power…
Then it would probably be wise to invest in the 320watt supply if I upgrade to a better heat bed later on.
[quote=“2stimpy”]I think i will go with the 600 w 25 amps 24 volt power supply.
This should be enough to get the heatbed to temperature very fast i think.
The question remains, will i need a better switch or will the switch made with edirols components hold up.[/quote]
As can be seen in the data sheet for the MOSFET in question, the maximum current at room temperature is 160 A at 10 V. Conversed to 24 V this amounts to about 65 Amps, so you should be fine (if my basic electronics knowledge doesn’t fuck me over on this).
The last few days i spend a lot of hours searching info about witch psu to use.
I can’t find any info on that, but i am sure the 600 w 25 amp should do the trick.
today I tried out another power supply for my heat bed. Perhaps the results are of interest for someone:
I use an additional supply only for the heating bed. Well, “power supply” is perhaps a big word for what I have, it is only a transformer with with a power cord on one side and two wires on the other. This one gives 24V and 100 VA.
My switch is a solid state relais so assembling is quite easy, only some wires.
With this configuration the bed heats up to 50C within 5 minutes, after 20 minutes it is at 90C. After 40 minutes the temperature reached 96C,.
Room temp was 19C, the printer is not chambered.
So 90C seem to be OK, but I’m not sure if this is enough to for printing with ABS on Kapton tape.
A good part to print with ABS would be a case for the transformer because it gets to hot (70-80C) for PLA.
I print ABS on borosilicate glass @ 110 C with a little bit of ABS slurry (ABS dissolved in acetone) with great success, using a 5 mm brim. Prints pop off easily when bed has cooled a bit. Earlier I also did this at lower temperatures around 70 as well, before getting the beefed up power supply. So that should work fine for you at about 90 C.
Haven’t got any experience with printing on kapton, but this is a good alternative.
[quote=“magu”]Earlier I also did this at lower temperatures around 70 as well, before getting the beefed up power supply. So that should work fine for you at about 90 C.[/quote]Hi magu, thanks for your hintsSo I will try the kapton first and if this fails I’ll try ABS slurry next.
today I tried out another power supply for my heat bed. Perhaps the results are of interest for someone:
I use an additional supply only for the heating bed. Well, “power supply” is perhaps a big word for what I have, it is only a transformer with with a power cord on one side and two wires on the other. This one gives 24V and 100 VA.
walo[/quote]
Doesn’t a 24V transformer give you 24V peak. You need the rms to get the power.
24/SQRT(2)=16.9V
Maybe why you don’t get as much heating as expected.
what does this normal or inverted means? I’m not that good with this kind of stuff (that’s the reason i bought this printboard and did not assemble it myself)
The only thing I can think of is that the output + becomes - but that just sounds stupid…
And by the way, if you look closely, the normal “jumper” looks like it is already connected to eachother…
what does this normal or inverted means? I’m not that good with this kind of stuff (that’s the reason i bought this printboard and did not assemble it myself)
The only thing I can think of is that the output + becomes - but that just sounds stupid…
And by the way, if you look closely, the normal “jumper” looks like it is already connected to eachother…[/quote]
As you suspected, inverted means LOW on signal -> HIGH on the high power output, and vice versa.
Conversely, normal means HIGH signal -> HIGH power output.
what does this normal or inverted means? I’m not that good with this kind of stuff (that’s the reason i bought this printboard and did not assemble it myself)
The only thing I can think of is that the output + becomes - but that just sounds stupid…
And by the way, if you look closely, the normal “jumper” looks like it is already connected to eachother…[/quote]
As you suspected, inverted means LOW on signal -> HIGH on the high power output, and vice versa.
Conversely, normal means HIGH signal -> HIGH power output.[/quote]
So in this case I just need to solder the “normal” connections together?
Do I have to change the wires that are currently used (ribbon cable) or should it work?[/quote]
