Dual power supplies
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@zapta I think I'll go with a heated bed with its own 120v power. That way, I can get the 700watt heater.
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I have an idea. Please confirm the logic is sound. Couldn't I combine my 2 power supplies of 320watts to make 640watts as shown in the diagram? This should satisfy the 400watt heated pad, right?
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Yes, this would work. One of several caveats: If a power supply ever fails, or is just turned off somehow, while the bed is running, the 'other' power supply will be overloaded and either thermal shutdown or fail.
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I think this is a bad idea .... you can't guarantee that the load will be shared equally. In theory it will work but IMHO it is poor design.
Go with your 120V bed heater, that will be the optimal configuration. -
@jens55 said in Dual power supplies:
I think this is a bad idea .... you can't guarantee that the load will be shared equally. In theory it will work but IMHO it is poor design.
Exactly so. The two PSUs won't share the load equally.
Meanwell sells a 24v 480W PSU. You could use one of those for the 400W bed heater.
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@dc42 Thanks guys for letting me bug you with ideas. I will go with the heated bed with its own 120v power. It is the most sensible route and costs less.
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@Weevil mains powered heaters are usually cheapest BUT, BUT, BUT, BUT !!!!! pay attention ... especially with high power ones!!!
normally printers come with underpower bed heaters intentionally, they size them so that if they are "always-on" they can't overheat the bed (usually they reach equilibrium around 100-120C) but they take age to reach set temp... now when you put a "properly sized" heater that will reach set temp in 20-30sec that heater will reach equilibrium around 400 or 700C and can cause fire if it goes into "always-on" mode ... and triak can easily die in "conductive dead" contrary to what we'd like (open-dead) setting heater to "always-on" leading to fire!!!
There are 2 general solutions for this
- dual triak, so if one is dead the other will not be
- thermal fuse
I don't go the first way as, while ppl calculate the odds are crazy low it happened to me few times on non 3d printer machines, especially with triak's from non reputable sources so I don't trust that solution... (note, all those ssr's you find for under 40-50$ they are with PRC made low cost triaks)
So, I go with thermal fuse solution... they work like a charm and they solved me call to firefighters more than once
talking about this: https://www.aliexpress.com/item/32884513591.html
there is a type with spring
and without spring
both should get the work done ...
you attach it to your bed and you power your whole printer trough it, or you only power your bed trough it, depending on what you like better .. when the fuse gets melted the power is cut, you can't reset it, you have to replace it .