Re: MOSFET specs for RAMPS
Thanks, that makes much more sense now. So I can see that the mosfet I suggested would be ok for low current devices, but not for switching a heatbed, and the gate series resistor explains the...
View ArticleRe: How do I properly measure the current of power supply?
If the PSU has two separate 12V outputs, connecting them together is a bad idea. One of the outputs is likely to regulate to a slightly higher voltage than the other, and will end up taking nearly all...
View ArticleRe: How do I properly measure the current of power supply?
... measuring higher currents, than your amperemeter can suffer, is made by shunt resistors - you simply measure the voltage drop of a defined resistor and calculate the drawn current with Ohm's law....
View ArticleRe: SmoothieWare Compatible Mainboards
This "new" Smoothieware-compatible board popped up in the Google Deltabot group over the weekend: http://itcorp24.cart.fc2.com/ca8/48/p-r8-s/ Momoinololu M3[Rev 1.0] I know that cxandy knows about it,...
View ArticleRe: MOSFET specs for RAMPS
An IRLB/U 8743 easily switches 20 amps without even needing a heatsink and this resistor on the SevenSwitch (10 ohms) ist just a protection measure.
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Re: How do I properly measure the current of power supply?
I hooked up 10W 10 ohm resistor, 55W 12V headlight bulb, and two 55W 12V headlight bulbs in parallel to check voltage and current. Measurement of voltage and current of each load: 10W 10 ohm resistor,...
View ArticleRe: How do I properly measure the current of power supply?
1. You can identify two 12V positive rails by a label on the PSU that gives two separate 12v load limits for output 1 and output 2, and by observing that the +12V wires coming out of the PSU are...
View ArticleRe: SmoothieWare Compatible Mainboards
Here's yet another Smoothie-compatible board that someone posted in the Deltabot forum: http://hackaday.io/project/833-3dpcb-smoothieboard-compatible-driver-pcb Looks like it may be a dead project...
View ArticleRe: MOSFET specs for RAMPS
Actually I found IRF2804 which I think should be a good substitute VDSS = 40V RDS(on) = 2.0mΩ (at Vgs 10v) ID = 75A
View ArticleRe: MOSFET specs for RAMPS
Thr IRF2804 may not be a good choice due to the Vgs(thr) rating (look at Fig 3 for 5V). Most heatbed drivers are controlled by the MCU directly so you need to select what is commonly referred to as a...
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Re: How do I properly measure the current of power supply?
There was little progress. I had an advice from few members in the Reprap irc chat which was to install a load in positive 5V rail. So I installed two 10 ohm 10W resisters in parallel to the positive...
View Articlemotors not responding
Hello guys, i have a problem with my reprap, i have marlin firmware, amd i'm using pronderface. the printer is ready, when i 'm testing it to pronterface if i send a command to movr one motor it's...
View ArticleRRD GLCD startup problems with new psu
Hi Folks, I have a smoothieboard and RRD GLCD which were getting along fine until I switched to my new bigger PSU ( that can cope with my new 200W hotbed). Now the LCD doesn't seem to be initialised...
View ArticleRe: RRD GLCD startup problems with new psu
On the Azteeg X5, several people have reported that powering a GLCD from the on-board 5V supply causes similar problems. Mine was a coin toss as to whether it would display the Smoothie banner or...
View ArticleRe: RRD GLCD startup problems with new psu
Well my 5V is coming from the same regulator in both cases, working with old 140W 12V PSU and not working with new 1100W(!) 24V PSU (it was a surplus bargain on ebay). The regulator is a switcher...
View ArticleRe: RRD GLCD startup problems with new psu
Nope, delaying five seconds before the init made no difference. Hitting reset on the smoothieboard doesn't sort things out either.
View ArticleRe: RRD GLCD startup problems with new psu
How does the voltage on the 24V supply look when you power up the printer? Does that monster supply need a minimum current to help it keep the power regulated and clean? (Some of the ATX supplies need...
View ArticleRe: How do I properly measure the current of power supply?
Quotedc42 2. The trouble with using auto bulbs as loads is that they take a very high surge current when you first turn them on. It may be this surge current that is tripping the PSU. I had to agree...
View ArticleRe: SmoothieWare Compatible Mainboards
QuoteTraumflug That said, glad to see so many other 32-bit boards. kthx on IRC currently counts 10 such designs. The only really adorable thing about Smoothie is its marketing. Arthur got that really...
View ArticleRe: SmoothieWare Compatible Mainboards
Worth pointing out that it's not just the Smoothie that has more user-friendly configuration, better step pulse timing, more precise acceleration etc. because RepRapFirmware on Duet electronics does...
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