Power Supply Amperage Help! October 20, 2014 06:07PM |
Registered: 9 years ago Posts: 10 |
Re: Power Supply Amperage Help! October 21, 2014 06:50AM |
Registered: 13 years ago Posts: 7,616 |
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Re: Power Supply Amperage Help! October 21, 2014 09:37AM |
Registered: 9 years ago Posts: 10 |
Re: Power Supply Amperage Help! October 21, 2014 02:05PM |
Registered: 10 years ago Posts: 869 |
Your heated plate will draw as much current as it can get up to V/R amps where V = your voltage and R is the resistance of the heated plate. Depending on how your plate was designed, that may be limited to around 11 amps. Or it could be more, or it could be less. If it wants right at 11 amps or more, then expect the polyfuse to trip. If your bed specs are out of whack from what's typical, or you want to use a more powerful heated bed, you'll need to use a relay (solid state or mechanical) that is controlled via D8 that is rated for the current that you are needing and hooked up to a power source that can handle the load.Quote
Evmanw
Now for my questions: Can my heated bed plate be more than 11A if I buy a power supply capable of giving that much power? Is anything else using power from that half of the power terminal?
You're not overthinking, but it's not just add up all the current ratings and that's what you need. It's more complicated than thatSteppers due to how they operate have a constantly changing current requirement as each winding energizes and de-energizes for each step (or microstep). ~5A usually is all that is needed for the extruder, electronics, and motors.Quote
For the other half of the power terminal, I guess that I will need at least 6 Amps for the stepper motors plus some power for the Arduino and fans etc. or am I overcomplicating things because I will theoretically never have all four motors at full speed at once?
You don't decide how much power goes in. Electronics, whether they are a micro controller, stepper motor, or heated bed, draw current...the current isn't pushed to it. You just need to hook up the wires, usually 2 or 3 are sufficient to each connector. The ATX specification says that the yellow wires are +12V and the black wires are ground. Those are the only two that you need aside from the typically green PS_ON lead. All the others can be taped off or snipped as you won't need them. The one exception to this is that some power supplies need a load on the +5V rail in order to have full power on the 12v rail. When selecting a power supply, don't look at the overall power rating of the power supply (typically 300-500 watts or more). The only thing you are concerned about is the rating of the 12v rail. In the Maker Geeks case, that is 22 amps which is sufficient. If they list a wattage instead of a current rating, divide the wattage by 12.Quote
Also, how do I know how much power goes into each half of the terminal when purchasing a power supply? I found: http://www.makergeeks.com/5012siatxpos.html which has a nice tutorial on how to install it. It shows this on the bottom of the page. Can someone help with interpretation?
DC Output Specifications:
+3.3V, 22A
+5V, 30A
+12V, 22A
-12V, 0.8A
+5VSB, 3A
Re: Power Supply Amperage Help! October 21, 2014 09:47PM |
Registered: 9 years ago Posts: 10 |
Quote
cdru
You don't decide how much power goes in. Electronics, whether they are a micro controller, stepper motor, or heated bed, draw current...the current isn't pushed to it. You just need to hook up the wires, usually 2 or 3 are sufficient to each connector. The ATX specification says that the yellow wires are +12V and the black wires are ground. Those are the only two that you need aside from the typically green PS_ON lead. All the others can be taped off or snipped as you won't need them. The one exception to this is that some power supplies need a load on the +5V rail in order to have full power on the 12v rail. When selecting a power supply, don't look at the overall power rating of the power supply (typically 300-500 watts or more). The only thing you are concerned about is the rating of the 12v rail. In the Maker Geeks case, that is 22 amps which is sufficient. If they list a wattage instead of a current rating, divide the wattage by 12.
Re: Power Supply Amperage Help! October 22, 2014 12:24AM |
Registered: 14 years ago Posts: 1,092 |
Re: Power Supply Amperage Help! October 22, 2014 08:59AM |
Registered: 10 years ago Posts: 869 |
Correct. One other thing to look out for is if the supply has just a single 12V rail or two (or more). Sometimes the power regulation is split up to use multiple lower-power circuits than a single higher-power one. You can still use such supply (presuming each rail meets the necessary power requirements) but you just need to make sure you combine wires from the same rail. Obviously a single rail design is easiest as it's a non-issue then.Quote
Evmanw
Ok, so I am not hooking up "two different sides" (an 11A and a 5A) for the RAMPS board. Instead, the electronics (heaters, motors, etc.) are all drawing current from the 22 amps which is available?
Re: Power Supply Amperage Help! October 22, 2014 01:44PM |
Registered: 9 years ago Posts: 10 |
Re: Power Supply Amperage Help! October 22, 2014 03:16PM |
Registered: 10 years ago Posts: 869 |
Do you have a link to a product page? 10.3V sounds like a really strange voltage. Is the heater specifically made for 3d printing? Or is it for something else that that you are repurposing it?Quote
Evmanw
Now, I purchased a heater and I just realized that it runs at 10.3V. Is there any way while still using the same 22A 12V power supply from MakerGeeks (link above) to be able to run this heater?
Re: Power Supply Amperage Help! October 23, 2014 04:49AM |
Registered: 13 years ago Posts: 7,616 |
Quote
Evmanw
Now, I purchased a heater and I just realized that it runs at 10.3V.
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