Contact resistance critera/passing range (low voltage air circuit breakers)

[rizza_gay]

Good Day!

What is the criteria/passing range and standards for the Contact Resistance Test of Low Voltage Air-Circuit Breaker?

Specs:
ABB Manufactured with Iu=1600A, Ue=690V , 3 phase.....

Among the 4 units I tested for its contact resistance, 3 of it has a higher values. Injected current is 100A AC.
ACB #1 : 1435 micro ohms ; 1331 ; 847.7
ACB #2 : 269.6 ; 790 ; 670.8
ACB #3 : 22.8 ; 22.4 ; 22.3
ACB #4 : 40.0 ; 39.6 ; 36.5

Note that all ACB were at the same specs....


Thank you.

Godbless.

Regards,
Rizza

[Sanjayo]

Greetings Rizza! All three pases should be within 50% of the lowest value.

Example: 22.3 being lowest value, contacts should not be higher than 33.45 (22.3 x 1.5).

[dnigra]

at 100 amps...i would give those first two a good cleaning..should drop significantly

[rizza_gay]

Thanks a lot. . .

Is that from NETA standard?

Regards,
Rizza

[Sanjayo]

Yes, the +/- 50% rule comes from NETA. Are these new breakers?

Thanks a lot. . .

Is that from NETA standard?

Regards,
Rizza

[rizza_gay]

Thanks a lot. . .

Is that from NETA standard?

Regards,
Rizza

Yes...those were new ACB. . .

[rizza_gay]

Yes, the +/- 50% rule comes from NETA. Are these new breakers?

Yup...All breakers were new. One thing I've noticed is that the breakers were in Open Position before I conducted the test. Maybe, the presence of dusts in its contact matters.

[Sanjayo]

What kind of instrument are you using to measure?

[rizza_gay]

What kind of instrument are you using to measure?

Its the DV Power CAT66 : Circuit Breaker Analyzer

[Sanjayo]

Its the DV Power CAT66 : Circuit Breaker Analyzer

Did you say this was 100A ac? Using Dc current would give more stable reading.