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Topic: ok you electrical geeks (Read 1128 times) previous topic - next topic

ok you electrical geeks

im at work,,
Have 11) 2000AH battery stacks each with 1200A disconnects tied to my 8000A rated collection buss that feeds my 10000A dc plant.

Each disconnect has an internal shunt (50mv / 800A).

I have a shunt monitoring module that all the shunts wire to capable of monitoring 16 shunt inputs. 

I read one value up at the battery disconnect but 50ft away, at the shunt mux module, i am getting fluxuations.  IM thinkin harmonics in the room of some sort but not sure how to rid myself of it.  The DC shunt leads cant be shielded,, normally they are not. 

The one thing about the power room is these new energy saver flourecent lamps,, the narrow bulbs near my cable rack. 

I wonder if they are injecting harmonics on my wires since its such a low voltage?

The only thing i can think of is possibly i should jumper my remaining unused shunt input terminations to reduce noise.

I have two 450A load banks bonded to the collection buss to load the battery strings in order to achieve a couple of things during comminssioning.  Since i charged the batteries and equalized them properly, I assumed all my shunt readings would be near equal at the disconnects and read the same at the shunt mux module (excluding any minor voltage drop across the wires which is 18awg red and black RHH / RHW.

My disconnect readings are pretty close but fluxuations are happening 50ft away at the shunt mux.  This makes a huge problem because while on SNMP, i can see each string fluxuating,, therefore so will the customer at the network operations center.

ok you electrical geeks

Reply #1 –
Are the monitoring shunt inputs running parallel in the tray? if they are is there a divider in the tray? when you say that you should try and terminate the unused input terminations are you talking about just jumpering them all together or actually landing them on something
87 TC
HO Swap, T5 Swap, Mach Springs, CHE Upper and Lower control arms, Mach Chin spoiler, soon to be Procharged.

:evilgrin: Nitrous is like a hot chick with an STD you want to hit it but are scared of the consequences. :evilgrin:

ok you electrical geeks

Reply #2 –
they are all consolidated within thier own path on newton D rings
two week old pic of batts,,
no pics of shunt wiring path but the newton clips attach to the cable rack and you space the d rings out bout every 9'' or so to support all the 18awg 1pr wires.

yes they are on the same cable path,, twisted pair dc cables.

ok you electrical geeks

Reply #3 –
Quote from: bigbada1;312438
Are the monitoring shunt inputs running parallel in the tray? if they are is there a divider in the tray? when you say that you should try and terminate the unused input terminations are you talking about just jumpering them all together or actually landing them on something


what i mean is the unused shunt inputs have a + and - avail for an input.

I am thinking i should jumper the plus and neg of the unused input to eleminate the ability of the shunt mux to float.

Im gonna try that first.,, just never had to do it before although i remember hearing about this in "theory".

ok you electrical geeks

Reply #4 –
Looking at your pic you might be on to something with the lighting have you tried taking the reading with the lights off flourcent ballists do give off alot of noise
87 TC
HO Swap, T5 Swap, Mach Springs, CHE Upper and Lower control arms, Mach Chin spoiler, soon to be Procharged.

:evilgrin: Nitrous is like a hot chick with an STD you want to hit it but are scared of the consequences. :evilgrin:

ok you electrical geeks

Reply #5 –
yeah,, gotta stand still for 45min and they go out on thier own.

no controls other than network.,,,,stupid

Id have to aske permission to tinker with thier sensors to bypass them.  stupid hang ups!

ok you electrical geeks

Reply #6 –
duhh,, pulling light bulbs here in a little while:hick:

ok you electrical geeks

Reply #7 –
HAHAHA the light bulb came on to get the lights off lol
87 TC
HO Swap, T5 Swap, Mach Springs, CHE Upper and Lower control arms, Mach Chin spoiler, soon to be Procharged.

:evilgrin: Nitrous is like a hot chick with an STD you want to hit it but are scared of the consequences. :evilgrin:

ok you electrical geeks

Reply #8 –
strapping the vacant shunt inputs worked.  I prob better frame ground the relay rack the shunt mux, ADIO , Thermal runaway gear and fuse panel is mounted in.
 

ok you electrical geeks

Reply #9 –
I nailed it,, the thermal runaway card is producing a harmonic on the shunt side of the alarm card,, isolated it today when one of my relays smoke checked.