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Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
Hi

Can you plz confirm the lifetime of the relay? (Number of operations)
I have googled the data sheet. It is not available even on Siemens website. It seems it is replaced with new version. Relay was installed in 2006.




RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

You may wish to ask Siemens. I understand that Siemens perform reliability prediction tests as an integral part of their development process obviously to ensure their products will survive in the field over the intended design lifetime. However, there are many factors that affect lifetime of a product like ambient temperature, vibration, humidity etc. You may also wish to know that case studies on smartphones, TVs, washing machines and vacuum cleaners have shown that these product types all have average actual lifetimes that are at least 2.3 years shorter than their designed or desired lifetimes.
Esperantes

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

For many microprocessor relays the lifetime is about 20 to 30 years, depending on the brand. That said, some relays have failures before that, but I am expecting that you are asking for when to replace one that is in service.

I don't know specifically about Siemens brand, but I do know GE relay life is about 20 years, and others up to 30 years.

If you are asking about an electromechanical relay, I removed some that were working after 75 years.

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

As a general rule, relays such as those will be rated for a minimum of 1 million electrical operations at rated load to a maximum of 10 million mechanical operations. How many years that comes out to depends on how often they are operated under load. So for instance if the relay is operated at rated load once per minute, 24hrs per day, 365 days per year, it will last about 2 years minimum. If it is operated 4 times per day 365/yr, it will likely disintegrate sometime after your grandchildren's grandchildren die.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

Usually what will happen is that the contacts stopps working before it's mechanically broken depending on if it is DC or AC current you over the contacts, DC is worse winky smile and depending on the effect broken.

This is sheet is not for Siemens relays but I would say they are quite compatible.



Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
I have seen that there are RC surge arrester on the relay & contactor coils according to the wiring. Physically I can see the RC surge arrester on the 2 relays. However on the Motor Contactor I do not see the RC surge arrester.
Is the RC surge arrester integrated inside the contactor coil?
Plz see attached the wiring and some pictures.
Can you plz advise?

If there is no RC surge arrester on the contactor coil, the contact 13-14 on relay KA2 will be damaged soon?












RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

It has a built in varistor on the coil. (Mit Überspannungsschutz der Spule (Varistor))



1) When using the 3TF6 vacuum contactors in the vicinity of frequency converters, we recommend ordering a special variant:
3TF6 ...-....- Z A02.
The 3TF68 / 3TF69 vacuum contactors are included in the basic version integrated overvoltage damping of the main current paths.
When operated in circuits with z. B. DC converters, frequency converters, variable-speed drives, this wiring is not required.
The wiring can be damaged by the generated voltage peaks and harmonics and therefore lead to phase short circuits.
The contactors can therefore optionally be supplied without integrated overvoltage damping. Without extra charge.
Then add "–Z" and order code "A02" to the article number.
2) For the use of 3TF68 vacuum contactors with IE3 / IE4 motors 8.5 times the starting current, please use 3TF69 vacuum contactors.
For more information on design and project planning, see page 3/7. 3) Use of the 3TF69 vacuum contactors with IE3 / IE4 motors on request.
For accessories and spare parts, see pages 3/139 to 3/142

I could only find the german catalog, didn't put any effort in finding a English one, since the answer for your question was there. winky smile

https://cache.industry.siemens.com/dl/files/995/10...

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

I am not shore what Plz stands for ?
Is it a safety module / function or is it a brand ?
I can see you have a emergency button on the drawing..

I have worked a lot with building safety applications for people and machines.

I am not shore if that is what you are asking for. ponder

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
Thanks a lot RedSnake

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

You are welcome.

/Anna

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

The 3TF contactors are vacuum contactors and the coils on them are DC to help avoid bouncing of the vacuum bottle contacts inside, so even if you order it as an AC controled version, there is a little circuit board that accepts the AC signal and converts it to DC to operate the coil. That has surge suppression built in.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
Sorry I did not mention earlier that our power plant tripped following fault on the relay. We noticed several times after we started our FD fan on the boiler, it stopped. We replaced the relay and restarted the plant. After we replaced the relay, it was ok. We suspect the contact 13-14 on the relay is faulty.

Can the integrated varistor in the contactor coil be faulty? How can we test it? Can we add a second RC module (Siemens 3RT1916-1CD00) in parallel on the contact 13-14 of the relay as there is on the relays coil A1-A2?

We have 2 power plants identical and 15 motors with soft starter & bypass contactors similar as the FD fan. So this problem can happen again on any 14 other motors which are critical for the power plants and may cause a power plant trip.

The power plant was constructed in 2006. What do you advise us to do?

Should we replace all relays and all contactor coils to prevent such problem to occur again?


RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

13-14 is a N/O contact. I had a similar problem on my VFD and a N/O contact on a timer used to stop my drive. The drive had been operating without any issue for 15 years. We found that the culprit was dirt and dust contamination. All solid state contacts, mostly used for the powering of the cooling fans, were cleaned with the use of a contact cleaner and we have been operating without any stoppage for more than 6 years now. You may also wish to use dust-tight design contact. I know that Eaton and Schneider used to make them.
Esperantes

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

First of, it hade been easier if you hade verified by measuring that it actually was a bad contact on 13-14.
Less guess work that way. winky smile
Secondly what hade tripped DJ3, DJ4 or DJ5?
How often does this fan starts in lets say a week approximately?

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
None of DJ3,DJ4,DJ5 tripped

DJ4 & DJ5 are for motor heating.

We estimate that the FD fan stop/start around 10 times per year.

I have not been able to physically check the relay contact as I am working from home. I am giving info based on colleagues feedback.

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

Okey.

Quote (SA07)

that our power plant tripped following fault on the relay. We noticed several times after we started our FD fan on the boiler, it stopped.

What tripped ?
And was it stopped because 1. -KMC1 fell? or because -KA2 fell ?

My personal experience, is that it isn't reasonable that contact 13-14 on -KA2 should became so bad,by breaking a 230 AC voltage if it only has been done 150 times since 2006.
Is -KA2 and -KMC1 pulled constantly (motor running all the time) or is the started only for shorter periods?

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
The boiler FD fan tripped.
It stopped because KA2 opened and KMG1 opened.
The FD Fan operates 24/7 365 days except during annual maintenance or trips.
KA2 & KMG1 are closed constantly.

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

For me the word trip means that a engine protection, circuit breaker, safety monitoring equipment or soft starter with alarm has fallen out (tripped).
I am not sure if that is what you mean or if you mean it just fell out (stopped pulling)?
I assume the starter -G1 is used to ramp up when starting, and then -KMG1 takes over?
Cant see in your drawing what controls -G1 or how the shift over is constructed.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

More questions.
The first time it stopped was it when it was running by it's on?
Or did someone stopp it manually and then it stopped when they where trying to start it again?
The person that changed the relay do they stil have it?
Or if it was thrown away can it be retrieved?

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
Our Power plant was operating. The FD fan stopped. So the Boiler stopped and the Power Plant stopped.

The relay is with a colleague. I will check it when I resume work.

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

If the drawing you posted 15 Apr 21 06:27 is another then the first one, you need to change the name otherwise I can only get the same drawing twice.

For the relay I would first take a way the RC suppressor and ohm measure the coil to see if it is OK .
Then I would ohm measure the RC-suppressor or if you have a capacitor measurement instrument I would use that as long as it is not 0 ohms or endless it’s probably OK.
But if it is 0 ohm the CJ3 should have tripped.
If this is OK I would put the RC- suppressor back and connect 230V AC to the contacts 13-14 and a switch to the A1-A2 so I could turn the relay on and of and measure the voltage over the contacts it should be 0 V AC when pulled and make test 10-20 times to check if it is ok and if that is OK .
I would take the relay apart and look at the contacts.
I still thinks it is highly unlikely that it is the contacts that are bad with so few on/offs.
We have a machine with Siemens relays that are 43 years old, we maybe have changed 10 of those relays in 30 years but it’s 110 AC.

What hapens is that you get a arc between the contacts when the relay falls.
How long the arc will burn depends on if it is DC current or AC current, with the same current the DC arc will burn until the airgap is large enough to “brake” it .
But for AC it will either burn until the airgap is large enough or when the sinus wave goes over the 0 current/voltage, which usually happens quicker.
The varistor in the the coil of -KMG1 will help putting it out.
That is why a contact with AC over it doesn’t get burnt as fast as a DC one.
And when the contacts have been burned to much it welds the contacts together and the relay will not fall when the coil isn’t powered any more.
It can also not get good enough contact when pulling.
But that happening on a already pulled relay, ponder hmm of course everything can happen sooner or later.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

(OP)
Thanks RedSnake

RE: Lifetime of relay Siemens 3ZX1012-0RH11-1AA1

Another question.
How big are the consequences when this happens?
It might influence what kind of solution that should be implemented.
And how much money that someone is prepared to put in to it.
If a better maintenance plan is enough or if some backup solution should be put in place.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

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