SoliForum - 3D Printing Community — How to select and install a silicone bed heater, SSR and PSU?

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (fxdata) — Thu, 22 Jan 2015 11:56:29 +0000

If you look at most items plugged into an ac outlet they have some sort of breaker or fuse. Yes the breaker on the breaker box will trip still no guarantee would do so before it fails.

The fuse you seen on amazon is a dc type, need an ac fuse. Found two different types one has the plug with the fuse. Other is just a fuse by it self. For the fuse size either 6 or 7amp.

Inlet Male Power Socket with Fuse Switch 10A 250V 3 Pin IEC320 C14

Screw Cap AGC Fuseholder Black

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Thu, 22 Jan 2015 04:27:17 +0000

I don't see any reason. I can say I am not a fan of the fuse but I think I already made that case.
In addition you'll be adding two more points of failure to the wiring. Your decision though.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (mdrVB6) — Thu, 22 Jan 2015 04:24:06 +0000

Ya I'm not trying to start a fire, thats why I'm here asking for help. I've never picked out a fuse or SSR before so I'm just trying to go by the numbers on the packaging. Do you see any reason why that fuse and SSR combo would not work? It looks like it would from my very limited understanding.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Thu, 22 Jan 2015 04:08:56 +0000

Experience and testing tell us to go with what we know works but your welcome to try something different. Of course if it isn't up to the task they melt at best and at worst catch fire.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (mdrVB6) — Thu, 22 Jan 2015 03:50:55 +0000

I can look for a fuse, that should be fairly easy to do. This 16 gauge fuse holder should work, right?

http://www.amazon.com/Scosche-0400ATCFH … r+16+gauge

Also, how is this for an SSR? It is a 40 amp and if the heater is only 4.35 amps this should be way more than enough and its cheaper than the McMaster SSR (of course).

http://www.amazon.com/40A-SSR-Solid-Sta … ywords=SSR

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Thu, 22 Jan 2015 02:48:27 +0000

True or let the relay be the sacrificial lamb in place of the fuse. I am assuming your plugging into a wall outlet that is ultimately on a breaker. Safety first but redundancy in this case really provides little extra protection.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (fxdata) — Thu, 22 Jan 2015 02:31:34 +0000

If your using 120 volts ac might consider putting an inline fuse in case the heater shorts. Would need to be attached from the hot side of the ac plug to the SSR. Rather be safe then have a major problem.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Thu, 22 Jan 2015 00:30:47 +0000

There is no polarity on the heater itself. You just want to make sure the wire coming from the wall outlet cord (should be black/hot) is the one going to the relay. The other 2 wires in the cord should be white(neutral) and green(ground).
With AC we really don't use the term positive and negative since the current alternates.
So it's Line or hot then neutral and ground.

And thanks Mod for a few days now trying to clean up the Press threads.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (mdrVB6) — Wed, 21 Jan 2015 22:58:53 +0000

Okay, so just to make sure: on my sketch, the red wire is the live line that gets switched, right? And the black is permanently into the negative socket. But there is no actual polarity on the bed heaters, right? So I just need to make sure I get the SSR right. I think I got it.

Well, okay, I guess I won't be cheap on the grounding! I sure don't want a 110 AC live platform!

PS: when did you become a mod? I just noticed. Thanks again for all the help and congrats.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Wed, 21 Jan 2015 21:21:45 +0000

You've got it as long as you are (ouput side SSR) switching the Hot wire of the AC and not the neutral. I assure you there is no reliable continuity between the moving Z platform and the chassis. This needs a ground wire between them because if for any reason the element in the heater should burn through it will become a live (110 AC) moving platform.
Make Sense?

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (mdrVB6) — Wed, 21 Jan 2015 20:43:14 +0000

Okay, I took your sketch and cleaned it up a bit and loosely illustrated they way I will construct it on the back of my printer. How does this look?

Will the bed wires even have a polarity? I know the input side of the SSR matters but does the output? I may try the double grounding on the case and bed but I'm pretty confident I can get a strong connection just doing it to the case. Thanks again for all your help!

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Wed, 21 Jan 2015 19:29:23 +0000

The really nice circle I drew is where the heater power cord is mounted to the case with a clamp. I also used that screw to attach the ground wire from the cord to the chassis. That is not a Rumba BTW

Then you want another wire going from that screw in the chassis up to the build platform and attach it with a screw. This is an old picture so the wire doesn't show up but you can attach the ground to any metal part on the platform. You may even be able to utilize an existing hole or drill in a new one.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Wed, 21 Jan 2015 19:17:29 +0000

I will get you a picture of the grounds but for now here is a diagram for clarification.

The idea of a power strip in the back is a good one. I just don't like splices on the supply side of a large load such as a heating element. You can't avoid the ones on the relay but in my opinion 2 is more than you want.

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (mdrVB6) — Wed, 21 Jan 2015 19:05:11 +0000

So if I run a separate cord, then my printer is taking up 2 plugs on my wall. I could deal with that but what if I just mount a power strip on the back of my printer and plug both the PSU and the heat bed into that? I think that should produce a similar result. Most other electronics don't behave badly having a bunch of them plugged into one power strip. Then I could have an easy on/ off rocker switch and also charge my phone from my printer, haha.

How would I even go about grounding it at the chassis of the printer and at the platform? I believe the bed heater only has 2 wires, N and L, and those would go as shown. What else would I even ground?

Re: How to select and install a silicone bed heater, SSR and PSU?

null@example.com (wardjr) — Wed, 21 Jan 2015 18:52:58 +0000

It looks "Pretty OK"
In this case you are going to want "Extremely OK" at the very least.
I would really recommend running a separate cord (3 conductors) for the bed heater. Not that your layout wont work but you are playing with real power and real risk of Shock. A good three prong cord with a ground connected at the chassis of the printer and also the platform is vital. Also a consideration is tying into the supply wires of your PSU could induce undesirable power spikes.