You can get that through UL or TUEV if done right. But be prepared for a whole lot more scrutiny than usual. For example with respect to connectors where the usual coaxial style barrel or some cheap audio jack won't fly.
And the argument "But Phihong did it ..." will carry as little weight as telling the judge in traffic court that all the others were going even faster ;-)
I would start by asking the connector people, neutrik, switchcraft etc, what they would recommend as a safe connector that could be used by people living in Florida
martin
DC connectors require considerations for "creepage distance". Likely a hard partition between the source and return. Such a connector system will merely be slightly physically larger than AC power links.
External supply to (say) 24VDC/5A and step it up internally?
Certainly what you suggest could be one, but the approvals might be more costly than Best regards, Spehro Pefhany
I've noticed most external power supplies (wallwarts,adapters) have safe voltages like 5V, 6V, 12V, 24V, 48V. I've yet to notice external supplies beyond 48VDC. Example:
What if my product idea needs an external 100VDC 1A power supply? (There's no space for the power supply inside the product.)
The product goes in an office and the cords will be accessible to the public. Typical approved wire for the cords are used.
Do I get into trouble with safety regulations? I believe the whole chain should be no more dangerous than an approved
D from BC British Columbia Canada
Plus a sufficient protection against accidental touching which tends to make the whole connection longer. Another concern is charge retention on capacitors inside the unit. IOW there could be an enormous amout of "zing" when touching the prongs on the unit after unplugging.
That's what high value (ohmic)"bleeder" resistors across cap banks are for.
Well, a 1M across the usual 100uF or so on a DC node won't do that much.
Safe enough so after an accidental death people will still be able to vote?
Joop
Years ago, some standards group(s) decided that mere mortals were not to be trusted with voltage beyond a certain threshold. Don't know the current status, but the number used to be 42.5V peak. There were also some numbers for total power capability. I think it had to do with voltage that stops your heart and power that catches your house on fire. That you can kill yourself by sticking fingers into the wall socket seems to contradict the theory, but that's just the way it is.
But I digress...
If you stay below the thresholds, you have many fewer pages of regulations with which you have to comply. That (and cost) is why you rarely see portable home electronics that plug directly into the wall.
It's a system partitioning issue that should be resolved before the first design review. Safety compliance requirements are in the product spec.
And yes, it's good practice to assume you're ALWAYS in trouble with safety regulations. Your opinions on relative safety carry no weight with the regulatory agencies nor the injured user who is suing you. Just bend over and comply. mike
skrev i en meddelelse news: snipped-for-privacy@4ax.com...
Make space, make a xxV DC -> 100V DC power supply that will fit or forget about it! You are heading towards endless pain with the nonstandard supply!!
BTW: Whats wrong with 120 AC regulated to 100 V DC? Prior art exists for that.
The wallwart has TWO functions: the output voltages are low enough to be shock-safe, AND there is current limiting against fire hazard. The low current limit means insulation and connectors are less safety-critical.
If you need 100VDC, the output is no longer shock-safe; if you need 5A, only sheathed cables comparable to AC types are fire-safe. So, the only remaining reason for the wallwart is to put part of your gizmo out-of-sight. That would be bad design.
And yes, of course a box that contains lethal voltages and operates in a wood/fabric environment with high likelihood of heat or sparks is 'trouble with safety' in every sense.
The same as for line power? Then you can bet that one fine days someone will plug a mains cable into it and ... *BANG*.
That may be an option. But not if the wall wart portion is huge and heavy. Also, it'll get banged around a lot.
I consided using IEC 320 connectors just like used for computer supplies.
But to cut costs, I thinking of using no connectors at all..
D from BC British Columbia Canada
Thinking about it. If I used a low voltage external supply, the internal step up electronics don't need a rectifier and don't need an isolated secondary. However, I still don't think I have space for the step up electronics. A 100Watt internal converter that's 9mm high.. That's a toughy.. Also, it's not elegant to use step down electronics and then add more electronics to step back up.
D from BC British Columbia Canada
It's a tight space for a 100W DC to DC converter. The gizmo is 9 mm high. (Lots of width available) Maybe it's still doable.. I might find some planar magnetics to make an internal 100W DC to DC converter.
I'm only concerned with prior art when lawyers know I have lots of money. :)
D from BC British Columbia Canada
If you have to go that route for some reason check these out:
They have reps in the US and the engineers in Germany can communicate in English. If you need a contact let me know.
[...]
Just an IEC 320 connection on the 120VAC side of the external power supply. :) Like on this supply.
Yup.... Anything that's accessible to the public is most likely going to take a beating. The cords might need changing. All sorts of freaky stuff can happen. I found one of my gizmos (in field testing) loaded with sawdust and drywall dust.. :( It's was debris from a renovation. I didn't think of that..
D from BC British Columbia Canada
Inelegant? Perish the thought.
You never did explain why only 100VDC input was practical.
RL
Nah, you can also convert. 9mm height is a whole lot of headroom for guys who regularly design VME-style cards. You can get magnetics for that (see my other post).
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