device needed to time record amps and voltage

zepfan

Does anyone know of a device that can be bought or rented that will record over time amperage, and voltage on an electrical circuit? We are having issues with a 460 volt, three phase 225 amp circuit breaker that trips intermittently? What I mean by intermittently is about every three to four weeks.It is for a sixty ton,four compressor air conditioner. The six fans are separately fused, the compressors all have phase monitors, but are not individually fused. We have checked the wiring, and megged each compressor. All seem ok. We were going to change the breaker to see if that resolves the issue, but the cost on the breaker is close to $5,000.00 and we want more evidence that it is bad before we replace it. Any suggestions would be much appreciated. Thanks to all.

GBart

I think Fluke makes one. Are you saying the breaker trips or the unit trips out? You could be having a voltage drop from the street, seen it and that's how we found and proved it, we left a meter for 2 days and it recorded high and low and at @ 6am every morning this area was having a huge drop off because the electric company did not add transformers etc as the area got more developed.

hot_rod

The power suppliers generally have that sort of equipment and will log data for you.

GBart

Here, check this out

https://www.fluke.com/en-us/learn/blog/digital-multimeters/event-recording-or-logging-with-a-fluke-287-289-digital-multimeter

GBart

hot rod said:

The power suppliers generally have that sort of equipment and will log data for you.

I wouldn't trust them. The corporation is never wrong, especially electric corporations.

ratio

I ended up purchasing one of these for that very reason. So far, it hasn't helped, but I haven't had time to really dig into things, and I'm on the very bottom of the amp resolution, ≈3A @ 460 volts.

The Fluke 287/289 is a nice meter, I have a 287, but only records one channel at a time.

Being a 480 volt service, you're probably going to need a real logger of some kind, all of the cheapies I looked at when I was researching things peaked at ≈250 volts. There are some deals that can be had on ePay if you are patient—I've had good luck with purchases, save the really cheap stuff from China.

I'm toying with getting one of these, and a bunch of transducers of various flavors. I'm convinced that if one can lay out enough data in the proper relations, the patters will become apparent.

SlamDunk

What you really need is this:

https://www.fluke.com/en-us/product/electrical-testing/power-quality-analyzers/three-phase-power-quality-meters/fluke-435-series-ii

We paid $7k for ours which is more than your breaker. However, if you use an electrical contractor, they may have one you can use for considerably less. You can monitor power before and after breaker.

ratio

SlamDunk said:

What you really need is this:

https://www.fluke.com/en-us/product/electrical-testing/power-quality-analyzers/three-phase-power-quality-meters/fluke-435-series-ii

Nice. This was on my short list, but Big Daddy refused to open the checkbook that wide, I had to settle for something cheaper. The Amprobe (now owned by Fluke, BTW) seems to do what it's supposed to, although I ended up with a defective CT out of the box. Fluke warranty service was an awful experience, I missed the 30 day sellers' exchange period by 1 day.

Protip: if you need breakers, get a price on a whole panel stuffed with the breakers you need. It's waaaaay cheaper to get a panel stuffed full of breaker than to get the breakers themselves.

Zman

I have this setup with a selection of CT's for different amperages. http://www.onsetcomp.com/products/kits/kit-ux90-kwh

It does exactly what you are asking and might well solve your problem. The state logger can be configured to log gas and water meters as well.

I suspect that your problem is more complicated than a simple surge. An issue with the phases seems likely. Is there a backup generator is the mix somewhere.

EBEBRATT-Ed

Just some things to check:
breaker load should not exceed 180 amps
Thermal imaging camera on terminations?
compressor contactor contacts checked?

Rapid short cycling can cause breaker tripping. You get their and the machine is down, reset the breaker the machine has a heavy load and runs ok. Sometimes something in the control circuit will do this....that's why the power checks out ok, HP, LP, oil pressure, leaking pump down solenoid?? You can wire tattletales across the safetys to find the tripping control.

Just some ideas, maybe you have already checked these things

Leonard

They rent power quality meters, which is basically what your looking for. Finds voltage sags/peaks measures amps, 3 phase.
I forget the manufacturer's name and model #s.

Read about them in commercial/industrial electricians magazine, EC&M

JUGHNE

There surely would be staging and or time delay for restart of these 4 compressors?
Or disable one at a time during light load conditions, leave it off line for several days if possible. The hard start motor may show up.

A FLIR camera will let you look at both sides of the CB.
Loose buss bar connections or load connections will transfer that heat into the CB by conduction and eventually trip it out.

Also if these pump down at the end of the cycle, then there could be short cycling for repetitive pump down to satisfy the LP switch.

GBart

Zman said:

I have this setup with a selection of CT's for different amperages. http://www.onsetcomp.com/products/kits/kit-ux90-kwh

It does exactly what you are asking and might well solve your problem. The state logger can be configured to log gas and water meters as well.

I suspect that your problem is more complicated than a simple surge. An issue with the phases seems likely. Is there a backup generator is the mix somewhere.

awesome, see if their backup generator is running a cycle when the unit trips, one place I know has their generators run every Monday at 6pm

zepfan

Thanks for all the suggestions on this issue. There is no generator on this job, and the circuit breaker has not tripped since i posted the original question. Thanks to all