Ammeter Theory of Operation - Printable Version

Ammeter Theory of Operation - Printable Version

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RE: Ammeter Theory of Operation - RussWhite - 10-07-2016

CT's for sure!
Russ

RE: Ammeter Theory of Operation - bikestuff - 10-07-2016

Thanks Russ. If I shut all power to the coach and disconnect inverters it should not be an issue to replace...yes?

RE: Ammeter Theory of Operation - RussWhite - 10-07-2016

That is correct. The issue is that if you spend the secondary of a CT that has current passing through the primary counter EMF will produce a nasty spark. Lab CT's have a shorting switch on the so you may short the secondary and then open it downstream with current in the primary, but that is not really cost effective for our purposed on a device that for many will never be disconnected from its load ( the amp meter ).

Another option would be to just open the main breaker so no current could flow through the CT's and do whatever it is you are planning to do to the meter.

Russ

Ammeter problems solved! - bikestuff - 10-20-2016

Update: (Success)

I found new meters but they were a different size from the existing meters (Slightly smaller). Ammeter Voltmeter These are high quality meters and are made to go in high end yachts. I have had good luck with Blue Sea Systems products.

The ammeter comes with its own CT so there is no problem figuring out the windings. I suspect the reason the old ammeter quit was a problem with the CT.

Since I was at Newell, I asked about modifying the panel which holds the meters. They had the original CAD templates and were able to cut a new panel with modified holes on their CNC machine in about 20 minutes. (Amazing! Go Team Newell!) Newell will hold onto the template so if you have a similar coach and have a 5.5 x 17.5 (ish) sized meter panel, you might be able to talk them into making you a panel. Talk to one of the service advisors for details.

Now I have working meters again...and retained the factory look. I included one picture of the label on one of the old Volt meters. It clearly says it is a DC meter. Go figure.

What I found was that the volt meters are fed with 120V and the ammeters used Current transformers. The wiring to the new meters was the same as the old meters. (The new meters come with backlights, however I did not see any purpose in that, so I did not connect).

ps. bonus Roro picture.

NOTE: We found that the heavy gauge wires in the breaker panel had been spliced using big crimp on type wire nuts. Two of the four connectors came off with no effort. They had not been crimped properly. So...if you find yourself in your breaker panel look closely at any splices for signs of arcing and heat. Mine had not heated up, but were certainly an issue.

RE: Ammeter Theory of Operation - bikestuff - 10-21-2016

Thanks for the help gang! Meters are working great! If you suspect that you might have a bad meter...let me know! One of the ones that I took out might fix your problem. I am not sure if the meter, wiring or CT were to blame for my ammeter not working but I will hang onto the old meters in case one of you guys has a similar problem.

RE: Ammeter Theory of Operation - dbld58 - 04-24-2022

Hi Bill - Thanks for your write up here, albeit almost eight years ago it is as helpful as it was yesterday.

I am unclear if you replaced your CTs, and if so, how did you wire them from back to front?

When you did the work did you simply shut off the main breakers to stay safe from shocks/shorts?

I am looking to replace my Volt and Ammeters, and ideally relocate them to above the entry door (front entry) where the antenna switched used to be. That would let me place nicer speakers in the cabinet areas on each side of the TV.

Thanks!

RE: Ammeter Theory of Operation - Richard - 04-25-2022

I don’t know if this will help you or not. And this is something that @"RussWhite" implemented. When I saw it, I thought it was incredibly creative.

Russ has a Progressive surge protector hardwired in the shore reel bay. Those protectors have a remote that uses a standard telephone connection from the protector to the remote.

He used the existing telephone circuit that Newell wired when the coach was new to carry the signal from the protector in the power bay to the telephone connection by the door. He mounted the remote display right by the door. It continuously cycles through the voltage and amperage readings for each leg.

The big thing to be aware of in this setup is that it would not monitor voltage and amperage from the generator unless you wired the surge protector after the xfer switch.

RE: Ammeter Theory of Operation - bikestuff - 04-25-2022

David,

I used the existing wiring and I *believe* that the Current Transformers (CTs) came with the meters from Blue Sea.

I like Richard’s / Russ’s idea of having a digital meter. ….though the analog ones are easier to see all at one time.

The wires that run from the CTs to the meter are not heavy and you might be able to run in the wire chase that is at the top of the coach wall. (Above the slides) but that will take a lot of disassembly to get to.

Another thought is to get new meters and extend the wires on the back of the meters. That might just work. Smile

. In my case I always thought that the meters themselves had given up….but it might have been a loose connection to the CTs.

Your mileage may vary.

Bill

RE: Ammeter Theory of Operation - dbld58 - 04-25-2022

Thanks guys. I would prefer to just extend the existing wires.

Lots of projects getting checked off lately. I am very thankful for all of the Guru help I've gotten. I would have been lost otherwise,

RE: Ammeter Theory of Operation - dbld58 - 05-02-2022

Hi Guys - I figured I'd try something a little different. I purchased two of these AC ammeters (one for each leg) because it provides Voltage and Amps in one meter:

https://smile.amazon.com/gp/product/B07JB9B2QL/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&th=1

My thought is to also install two of these DC power meters, one for the Engine batteries and one for the House batteries:

https://smile.amazon.com/gp/product/B07T8GN61Z/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Once I received the DC meters I realized the 100 amp shunt may not be big enough. There is a 300 amp version as well.

Does anyone know how many 12v DC amps are pulled from either battery banks and/or what size shunt I should get? Or maybe the first question should be - Is this a bad idea?

My idea is to install the AC and the DC power meters over the front entry door.  I have a small CNC machine at home to cut the black polycarbonate panel to the correct shape (pic below), including the terrestrial antenna controller. By doing all of this, it will open up the space over the driver to place a proper sized bookshelf speakers on either side of the TV (I like to listen to music). The receiver/amp will be hidden behind the TV.