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[GMCnet] IOTA Converter Testing [message #297766] Mon, 21 March 2016 11:56 Go to next message
Tony is currently offline  Tony   United States
Messages: 59
Registered: January 2016
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Member
Inch by inch, I am going through my GMC. While at Blaine's, I was trying to
fit a socket onto the forward airbag nut and got a tingling in my hand.
This after plugging into 110 power. Blaine's son Eric narrowed it down to
the IOTA converter. Seems the PO had the positive cable connected to
ground. Amazingly, the AC worked as did a few 110v lights.

So, I've removed the converter and wondered if anyone could recommend how
to test it or where to take it to be tested.

Also, if I need a new one, are there better options or is this one (IOTA
DLS-55 Series M) fine?

--
--Tony
​ Bennett
Watkinsville, GA
1978 GMC Eleganza​
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Re: [GMCnet] IOTA Converter Testing [message #297768 is a reply to message #297766] Mon, 21 March 2016 13:52 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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Registered: June 2008
Location: S. Ontario, Canada
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Are you plugged into a GFI (ground fault interrupter) outlet?

The positive output hooked to the body ground is definitely going to cause issues with the battery. BUT... you will not get a shock from 12 volts. The lights are all 12 Volt so they are getting power from somewhere. Incandescent bulbs do not care about power polarity, so they can work with reverse polarity if the battery was disconnected or missing.

If you have the OEM style electric hot water heater, a burn't out element can provide a path from the live side of the 120 Vac to the motorhome body.

Check with a ohmmeter on the motorhome power cord. You should not see any resistance to ground from either the neutral or the hot connector. You should see close to zero ohms from the ground pin to the body of the GMC.


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: [GMCnet] IOTA Converter Testing [message #297771 is a reply to message #297766] Mon, 21 March 2016 14:22 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Registered: May 2011
Location: Braselton ga
Karma: -74
Senior Member
Without seeing a schematic, I'm going to surmise that the supply is a switching supply, and that there's a capacitor or two - usually discs - across the incoming AC to the chassis to kill off the RF interference the supply generates.... and one or both are leaking. Plug it into a GFI outlet to test this theory. If it trips the GFI, I'd simply replace it, though you can chase through it and see what's leaking to the chassis. If it doesn't, then repower the coach and measure with your digital (for once) AC meter from the part that shocked you to a good ground such as the center pin on an outlet at your home. If you measure AC, keep disconnecting stuff in the coach till it goes away. Start with the water heater, a known leakage point.

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: [GMCnet] IOTA Converter Testing [message #297780 is a reply to message #297766] Mon, 21 March 2016 16:54 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
Tony wrote on Mon, 21 March 2016 12:56
Inch by inch, I am going through my GMC. While at Blaine's, I was trying to fit a socket onto the forward airbag nut and got a tingling in my hand.
This after plugging into 110 power. Blaine's son Eric narrowed it down to the IOTA converter. Seems the PO had the positive cable connected to
ground. Amazingly, the AC worked as did a few 110v lights.

So, I've removed the converter and wondered if anyone could recommend how to test it or where to take it to be tested.

Also, if I need a new one, are there better options or is this one (IOTA DLS-55 Series M) fine?

--Tony ​ Bennett
Watkinsville, GA
1978 GMC Eleganza​

Tony,

What you were feeling was indeed a ground fault. This condition can be deadly.
I take it that the ground fault could no longer be detected when the converter was disconnected. True?
If you can still detect this fault, that should become an immediate and very high priority.

I am sure I join others here that would like a more clear description than, "The PO connected the positive cable to the ground." This condition should keep a lot of things from working at all.

What this also may mean is that you have a possible failure in the coach AC wiring or however you attached to shore power. The shore power connection should have provided a ground path for the coach frame and shell. That is just exactly so things like this don't happen. If it does happen, you have two things to fix.

The function of the Iota DLS-55 is to maintain the house 12V system and it should have no effect on the A/C or 110 volt lights.
Speaking of which, 110V lights in a coach is a very rare thing. The coach was not built with any.

I suggest that you contact Iota. When I last had any dealings with them, there were good people there. We can hope.
There is nothing bad about a DLS-55 except it should have the IQ4 controller attached or get the type with it built in if you have to replace the unit. The other you will find is a favorite here (and for good reason) are the Progressive Dynamics 92XX series. A 9245 or a 9260 would be a good replacement you don't need the higher charging rate unless you are planning to be recovering the house bank from the APU (genset). To take advantage of the capability, you have to have very solid and short connections between the converter and the house bank.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] IOTA Converter Testing [message #297787 is a reply to message #297766] Mon, 21 March 2016 19:20 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Tony,

All good answers, but before getting deeply into any of them, go to
http://gmceast.com/technical/

There you'll find at least 3 articles related to the GMC electrical system,
by Rick Denney, Ken Burton, and Bob Hendrickson. You should study all of
them before jumping into the job(s) ahead.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com

On Mon, Mar 21, 2016 at 12:56 PM, Tony wrote:

> Inch by inch, I am going through my GMC. While at Blaine's, I was trying to
> fit a socket onto the forward airbag nut and got a tingling in my hand.
> This after plugging into 110 power. Blaine's son Eric narrowed it down to
> the IOTA converter. Seems the PO had the positive cable connected to
> ground. Amazingly, the AC worked as did a few 110v lights.
>
> So, I've removed the converter and wondered if anyone could recommend how
> to test it or where to take it to be tested.
>
> Also, if I need a new one, are there better options or is this one (IOTA
> DLS-55 Series M) fine?
>
> --
> --Tony
> ​ Bennett
> Watkinsville, GA
> 1978 GMC Eleganza​
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] IOTA Converter Testing [message #297789 is a reply to message #297768] Mon, 21 March 2016 19:56 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
RF_Burns wrote on Mon, 21 March 2016 13:52
Are you plugged into a GFI (ground fault interrupter) outlet?

The positive output hooked to the body ground is definitely going to cause issues with the battery. BUT... you will not get a shock from 12 volts. The lights are all 12 Volt so they are getting power from somewhere. Incandescent bulbs do not care about power polarity, so they can work with reverse polarity if the battery was disconnected or missing.

If you have the OEM style electric hot water heater, a burn't out element can provide a path from the live side of the 120 Vac to the motorhome body.

Check with a ohmmeter on the motorhome power cord. You should not see any resistance to ground from either the neutral or the hot connector. You should see close to zero ohms from the ground pin to the body of the GMC.



This is exactly what I wanted to talk to you about on the phone. If you are getting shocked, you have two problems.

1. You safety (earth) ground is not connected correctly or the cord is open.
That in itself will not shock you.

2. Something is putting voltage on the body. Either the coach is not wired correctly of something is putting voltage over to the body. As stated in the previous posting, the most common item is the electric water heating element.

You need to measure from the chassis ground of the coach to a known good earth ground on your shore power connection. If you see voltage then go look for what is causing it. The 12 volt side of the converter will not cause this problem. (Sorry Eric) I'm not saying the converter is not bad or wired incorrectly but it is not the cause of you getting shocked.

The first thing I would do if you can measure a voltage between the body of the coach and earth (shore power) ground is to disconnect BOTH (black and white) 120 volt leads to the water heater. Then see if the voltage goes away. If it does not go away then we will need to look at other devices or mis-wiring as the cause of the problem.

After you fix the voltage then we need to fix the wiring issue of your safety ground in the shore power connection.

Let's fix the stray voltage first and we can address the safety ground after that in a follow up posting.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] IOTA Converter Testing [message #297792 is a reply to message #297766] Mon, 21 March 2016 20:18 Go to previous message
jhbridges is currently offline  jhbridges   United States
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
Senior Member
Tony -
If you join us for lunch tomorrow (Tuesday) we can hash this out. Worst comes to worst, I can buzz over to Watkinsburg and see what's going on.

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
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