8/2/2019 Fluke 1750 power quality recorder

1/2

Application Note

Instant power replay

solves a breaker trip

F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y

After experiencing some nui-sance tripping of breakers in thesubpanel feeding the secondfloor of this industrial building,we installed a Fluke 1750 PowerRecorder at the subpanel togather information about power

usage.For several weeks, we expe-rienced no circuit breaker trips,and the recorded data from the1750 showed excellent qualitypower delivery.

The next week, using the cur-rent event detector with a 20A threshold to match the singlephase branch feeds, we dis-covered that there were severalevents where current exceededthe breaker trip rating. Whilethere were no tripped breakersduring the week, it was clearthat something was overloadingthe circuit to the point where abreaker trip was likely to happen.

A search of the facility foundan employee who had moveda Tenny temperature chamberinto a lab area and was usingit to perform elevated tempera-ture tests on some products. The

Figure 1. Current event view, top level events

chamber was on wheels andwas plugged into a standard120 V, 20 A branch outlet.

The power recorder capturedthe operation of the temperaturechamber and its effect on thepower at the sub-panel.

Data analysis

The current event view showsseveral events outside the 20 Abreaker tolerance curve. The lon-gest event is shown in Figure 1.

The event exhibits a doubleinitial current surge, followedby a sustained current over20 amps. Although the circuitbreaker did not trip during thisevent, its rating was exceededand it would be likely to tripoccasionally under similar con-

ditions. These conditions arefrequent during use of the tem-perature chamber, as can beseen in the graph above, wherethis event is immediately fol-lowed by another similar eventwhose beginning can be seen atthe right side.

Testing Functions

Case Study

Operator: Michael Gipe, Fluke PowerElectronics Engineer

Measuring tools: Fluke 1750 PowerRecorder

Tests conducted: Power qualityevent recording

www.netzerotools.com

Go To 1750 Products Page

www.netzerotools.com

1750

1750/B

http://www.aikencolon.com/fluke-1750-series-3-phase-power-quality-recoderhttp://www.aikencolon.com/fluke-1750-series-3-phase-power-quality-recoderhttp://www.aikencolon.com/fluke-1750-series-3-phase-power-quality-recoderhttp://www.netzerotools.com/http://www.netzerotools.com/fluke-1750-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750-3-phase-power-quality-recorderhttp://www.netzerotools.com/http://www.aikencolon.com/fluke-1750-series-3-phase-power-quality-recoderhttp://www.netzerotools.com/search.asp?keyword=1750+power+qualityhttp://www.netzerotools.com/search.asp?keyword=1750+power+qualityhttp://www.netzerotools.com/search.asp?keyword=fluke+power+quality

8/2/2019 Fluke 1750 power quality recorder

2/2

2 Fluke Corporation Instant power replay solves a breaker trip

Zooming into the initial regionof the event in Figure 2, we seethe turn-on loads of the temper-ature chambers dual compres-sor system. The first compressor

turns on with a large initialsurge, followed by the second-ary compressor surge. This loadprofile clearly identifies the tem-perature chamber as the cause ofthe overload.

Temperature chamber peakcurrent is 49.7 amps. In Figure 3,the sustained load is near25 amps.

We can zoom in further,in Figure 4, to see even moredetailed resolution of this ini-tial current surge. Note that the

phase A voltage sags during thiscurrent surge, but the voltagedrop is small, indicating that thepower feed at the sub-panel isvery stiff, and can accommodatesubstantial demand.

Conclusion

The power feed to the secondfloor is robust. The nuisancetripping is most certainly due totemporary overload of a standard20 amp appliance branch circuitfrom using an industrial tempera-

ture chamber on the circuit. Thetemperature chamber should beconnected to a dedicated branchcircuit, sized to meet the require-ments of the chamber, minimum20 amps.

Figure 2. Compressor activity

Figure 4. Interpreting voltage drop

Figure 3. Load evaluation

www.netzerotools.com

www.netzerotools.com

http://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.netzerotools.com/fluke-1750b-3-phase-power-quality-recorderhttp://www.aikencolon.com/fluke-1750-series-3-phase-power-quality-recoder