ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 ... 41 42 [43] 44 45 ... 55   Go Down

Author Topic: brain storm an optimal human safety system for back line  (Read 105660 times)

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #420 on: December 08, 2015, 02:04:04 pm »

As a mechanical designer for hire I have learned that this is VERY true.
If you build a better mouse trap the world will ignore you.  You need a good idea AND marketing.

I completely understand you not doing anything with this without UL approval.  Years ago I came up with a much improved car seat for children.  It allowed mom to get the baby in and out of the car without straining her back.  When I thought of marketing it I thought Babies, Cars, No way.
While I was working at Peavey, they got sued because a musician playing two 3-wire grounded Peavey guitar amps got between a RPBG and properly grounded outlet, resulting in 120VAC between the two guitars. It was very nice to have UL sitting at our table in court to testify that our products were safe and absolutely didn't cause the musician's death. 

I don't expect any major problems from my OD-1 but in my experience lawyers are always cheaper if hired before the incident, as compared to after.

I could be temped to just say never-mind because of the UL hassle (I don't need the meager beer money this might provide), but I think an outlet tester that actually works is important and might even prevent some injuries if made available and used by the live sound community. 

JR 
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 996
    • LBP DI Box
Re: brain storm an optimal human safety system for back line
« Reply #421 on: December 08, 2015, 06:09:46 pm »

While I was working at Peavey, they got sued because a musician playing two 3-wire grounded Peavey guitar amps got between a RPBG and properly grounded outlet, resulting in 120VAC between the two guitars. It was very nice to have UL sitting at our table in court to testify that our products were safe and absolutely didn't cause the musician's death. 

I don't expect any major problems from my OD-1 but in my experience lawyers are always cheaper if hired before the incident, as compared to after.

I could be temped to just say never-mind because of the UL hassle (I don't need the meager beer money this might provide), but I think an outlet tester that actually works is important and might even prevent some injuries if made available and used by the live sound community. 

JR
Complete agreement, and thank you
Frank
Logged
Not to Code

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #422 on: January 11, 2016, 01:00:40 pm »

After a few week hiatus I am back on the bench with OD-1 development.

Attached is the latest PCB layout. I changed to a round PCB that better fits inside the commercial plug housing.

I wrestled with an interim change to make the ground present circuit simpler, and decided to return to the earlier, slightly more complicated version that ignores noisy grounds with leakage current. In my judgement it is better to not falsely report that a ground is present, than see that there is leakage current in a floating ground. The open ground is already a fault that should require attention. So no more feature creep.

I momentarily thought about adding another (yellow) LED to report leaky ground current, but decided that would be too much information/complexity for a simple tester.

I need to chew on this for a couple days before releasing to make sure my UL spacings are adequate, etc...

When I get this final cut PCB I will start testing for insulation resistance and the like. Since I'm not going to buy or rent a megger, I'll roll my own 500V power supply (danger Will Robinson). What could possibly go wrong?

JR

PS: I added pads where a neon lamp could indicate 240V, not sure if I will keep this feature, but will test it. Again perhaps TMI.
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

frank kayser

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1412
  • Maryland suburbs of Washington DC
Re: brain storm an optimal human safety system for back line
« Reply #423 on: January 11, 2016, 02:57:15 pm »

While taking a walk today, I was thinking that I hadn't heard from JR's project.  Came back, and like magic, an updated post! 
Very happy to see things are moving after the holiday break.
FWIW, I agree with your decision on the ground circuit - not falsely reporting a ground present.
The additional yellow LED would have been a "nice to have", but that list could go on forever. 
Thanks for the update!
frank
Logged

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #424 on: January 12, 2016, 02:15:53 pm »

Just pulled the trigger on what hopefully is final cut.... Moved some stuff around to increase clearance from line and neutral... while UL only require 3/64" this is a small PCB so some tight fits.

Now in my spare time I can build my 500V PS for insulation testing.  :o :o

Not looking forward to arm wrestling with UL... Need to get them to change their spec where they require small print caveat in the instructions saying that these testers can't detect two hot leads... 8) 8) 8)  because mine does.

JR
[edit- boards shipped from china... 1-18  [/edit]
« Last Edit: January 18, 2016, 01:13:38 pm by John Roberts {JR} »
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #425 on: January 25, 2016, 02:07:20 pm »

got the PCB today but hole in the middle is not drilled out large enough.... oops.

JR
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

frank kayser

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1412
  • Maryland suburbs of Washington DC
Re: brain storm an optimal human safety system for back line
« Reply #426 on: January 25, 2016, 03:55:42 pm »

got the PCB today but hole in the middle is not drilled out large enough.... oops.

JR
Looks pretty snug around that hole to begin with...
Logged

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #427 on: January 25, 2016, 04:38:29 pm »

Looks pretty snug around that hole to begin with...

Yup the whole design is snug, and some parts are close to the hole to be away from mains voltage leads. UL spacing is something around 3/64" but I tried to give them a little more room than that.

The extra ring around the hole is some kind of keep out area...I have a bunch of parts where their keep out areas interfere... 

I'll figure it out, but it won't be easy to drill 3/8" holes in a 1" diameter PCB.

They may have received a warning and decided to do me a favor, but making it only 1/8" is too much help.

JR
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2258
Re: brain storm an optimal human safety system for back line
« Reply #428 on: January 25, 2016, 08:53:05 pm »

My guess is that an endmill in a drill press would work a lot better than a drill bit.
Logged
Steve Swaffer

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16416
  • Hickory, Mississippi, USA
    • Resotune
Re: brain storm an optimal human safety system for back line
« Reply #429 on: January 25, 2016, 09:10:25 pm »

My guess is that an endmill in a drill press would work a lot better than a drill bit.
I don't even have a drill press, but my roper whitney hand punch has die sets up to 9/32" so i can get pretty close with that.

JR

Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

ProSoundWeb Community

Re: brain storm an optimal human safety system for back line
« Reply #429 on: January 25, 2016, 09:10:25 pm »


Pages: 1 ... 41 42 [43] 44 45 ... 55   Go Up
 



Page created in 0.098 seconds with 23 queries.