Heated bed fuse blown?

Hello!
I tried hooking up a 24V 200W silicone heated bed (This one: [www.aliexpress.com] ) to my AZSMZ (smoothie clone) 3D Printer board. My PSU: 24V 20A
-The heater does not have polarity
-The fuse for the heated bed can handle up to 150A (I doubt I'd ever need that much)
-In a wattage to amperage converter, my heated bed will take up 8.5~ Amps max when the heated bed is turned on.

My 3D Printer was working fine before, and as soon as I hooked up the heated bed and set it to 60C for PLA, the fuse was smoking (after 5 seconds of power going to the bed, I felt the bed was warm so I think its working).

So why did my fuse blow if it could easily handle 8.5 Amps..? I even have a proper cooling fan keeping all components cool..

Also, since there's no way of fixing that blown fuse, what fuse could work to get the board working again? (Give me a specific name please as I know nothing about fuses)

I cannot use my printer due to the board's safety protocol when a fuse blows.

Thanks for any help/suggestions!

This board [reprap.org] ?

Those are poly fuses, they also have a voltage rating...

And I very much doubt they are rated for "150A"

They look like the same ones on a ramps which the bed poly fuse is only rated 11amps at 16volts

Please read the numbers of the side of the fuse (if its still readable)

You might be able to solder a new fuse on or replace it with an automotive one but 200w is a bit more than most printer boards can handle you would be best to use a mechanical relay or an ssr.

Quote
DjDemonD
You might be able to solder a new fuse on or replace it with an automotive one but 200w is a bit more than most printer boards can handle you would be best to use a mechanical relay or an ssr.

All the printer control boards I know of can handle at least 10A bed current. At 24V (which the OP says he is using), that's 240W. So his 200W heater should be no problem, unless it is faulty - although I think 200W is under-powered for a 300mm square bed.

Edited 1 time(s). Last edit at 04/07/2016 10:00AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Ah okay sorry I must have missed the 24v part.

I asked the supplier about the fuses and he may have added a 0 by accident to the 150A which sounded quite skeptical when I first heard it...

The Fuse has a X symbol and a "16" Below it are the characters "GF1100"

I can easily solder on a new fuse to the board, and I only plan on using the 200W Heated bed for PLA at around 60-70C

To replace this fuse, I should look for an automotive fuse? (a 15A one?)

Thanks!

Yes a 15A car blade fuse holder will solder in place of the solid state fuse

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

make sure the wires on the heater are solid connection wise then make sure they are tight in the terminal blocks. Personally I would use a separate power supply just for the bed heater