What am I doing wrong? There are four cutler hammer definite purpose contactors controlling an electric grill, two electric BBQ pits, make up air and misc outlets under a kitchen exhaust hood. The coils are all 230 volt. The contactors are "open" unless the coils are powered. The Ansul system microswitch opens on actuation shutting off power to the coils, which shuts everything down. I have been told this is the best fail safe way to go, and these contactors are that way. But geez, what a howl these thiings make! Voltage is a little high here, my meter is showing 244 volts. These things are really loud, is this normal? I see there is a DC coil conversion available. I just can't believe these things are normally this loud......Any help?
Noisy Definite purpose contactor,,Help please?
- Thread starter Fourlix
- Start date
- Status
- Location
- Massachusetts
I agree your method is more of a fail safe design but most of us just use shunt trip breakers for ansul systems.
I don't know what you can do to quite down what you have.
I don't know what you can do to quite down what you have.
buck33k
Senior Member
- Location
- Washington state and North Carolina
I had a real noise problem with CH contactors in a lighting system. They had a metal frame and may have been similar to the ones you described. I exchanged them for AB brand. It made a world of difference. I don't have a part # but they were a plastic frame contactor.
Fulthrotl
~Autocorrect is My Worst Enema.~
- Occupation
- E
you have singing E's and I's. this would be the problem.
assuming you are talking about the 60 hz hum when they are pulled in, here's
the problem.... the laminations are singing. i used to work in a place that
made transformer laminations. the E's and I's, as they are called.
when they stamp the laminations with progressive dies, the material must
be straightened within .005~.010" flatness by decoiling rollers, before stamping.
if it isn't flat, when the laminations are riveted together, there are tiny air
gaps left between laminations. when ac is applied, eddy currents between
laminations cause them to vibrate like reeds in a musical insturment, producing
a loud hum.
quality control on the laminations in your contactors must have been lacking.
really good iron core coils and transformers are pretty quiet. i've noticed, over
the years, in spite of hearing loss due to loud rock and roll, that transformers
are getting louder and louder.
dc doesn't hum like ac, so that might be your only remedy here. dc coils, and
a *high quality* control transformer to power them, like an AB...
there is also RIB, relay in a box, that makes some solid state stuff that might
work for you, depending on connected load. totally silent....
randy
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In my experience, dirty pole faces are a common cause of noisy contactors.
That is the surfaces where the two parts of the electromagnets come together.
If that's the problem, and it isn't too difficult or time consuming to do so, you could take them apart and clean them but just replacing them might be more cost effective.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Agreed. I have found that most contactor armnatures have pole faces that pivot. I have quieted noisy contactors by spraying a bit of WD40 on the pivot and working them free.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
I had a new retail distribution center that all of the contactors sang, the white powdery substance in the enclosure and on the contactors were dead a give away that the installers drilled the concrete wall to anchor the enclosure while it was still on the wall. Had to go around and blow out 32 contactors. A brand new service station in North Carolina caught fire when the installers did not sheild the factory installed contactors in a WA Brown gear from metal shavings while drilling holes in the top of the enclosure.
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
I had the same problem. The HO insisted on having some NO contactors installed in his Master Bedroom Closet (Please don't ask)
I mounted them in a plastic 12x12x6 junction and installed the cover in a way that left an air gap for them to breath.
About a month later they got "noisy".
I put a silicone isolation pad behind each one and made sure they were bolted tight to the junction box.
That was a year ago. No fire engines yet!
I mounted them in a plastic 12x12x6 junction and installed the cover in a way that left an air gap for them to breath.
About a month later they got "noisy".
I put a silicone isolation pad behind each one and made sure they were bolted tight to the junction box.
That was a year ago. No fire engines yet!
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
What's wrong with people? How can the need for addressing this stuff not be obvious?
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
What's wrong with people? How can the need for addressing this stuff not be obvious?
They are not stupid, just ignorant!
Thanks guys. I think I will try some cleaning, WD-40, and what are these silicone mounts/pads mentioned? The 4 contactors are not all the same volume of loudness, so everything you guys said makes sense. Quality control, as well as contamination, could both be issues, probably are. If, after cleaning, one or two are still particularly noisy, I will try replacing them.
chaterpilar
Senior Member
- Location
- Saudi Arabia
Can you check the voltage at the coil when they are ON.
Incorrect voltage (low) can cause them to chatter..(no connection to my user name..:smile
I had faced a similar problem once and found voltage to be 130 volts for a 230 volts contactor. (wrong tapping at the control voltage transformer).
As others have already said...dirt on the pole faces can cause humming.
Use blower to give them a nice airwash....
cheers.
Incorrect voltage (low) can cause them to chatter..(no connection to my user name..:smile
I had faced a similar problem once and found voltage to be 130 volts for a 230 volts contactor. (wrong tapping at the control voltage transformer).
As others have already said...dirt on the pole faces can cause humming.
Use blower to give them a nice airwash....
cheers.
quogueelectric
Senior Member
- Location
- new york
Threes a charm for contactor chatter. Magnetism is an inverse square function of distance take a little emery cloth and clean the surface that comes together when the magnet is on. It works wonders. A little dirt or surface rust can cause a lot of unwanted noise.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
First off, I have to admit a specific bias against Definite Purpose contactors, and I used to work for one of the largest manufacturers of them, Siemens (ex Furnas). In my opinion, DP does not stand for 'Definite Purpose", it stands for "Don't Purchase!"
A DP contactor is to the electrical control device world what a Yugo is the the Automotive world; a piece of junk that meets the absolute bare minimum requirements to be called functional. I should also point out that if you are in a State that requires NRTL listing of devices, you have violated the requirements by using them, unless you are a UL panel shop and have paid the copious fees for adding them to your procedure. DP contactors are NOT UL listed, they are UR, meaning UL Recognized. The difference is, you cannot install UR devices unless they are a sub component of a larger listed system, and even then, only after UL has thoroughly investigated exactly how your plan to use them.
Secondly, DP contactors, being the CHEAPEST junk that will do the job, are all notoriously noisy, even if clean and brand new. There is virtually no attention to detail in their design, in fact the only design criteria used is manufacturing cost (#1) and as I said, bare minimum functionality.
Thirdly, ALL DP contactors are now made in third world countries such as China and India. The better one's are made in India by the way, but when I worked for Siemens, who's products are made in India, they made a conscious decision to abandon that industry as far as future product development and promotion goes because they can no longer compete with the likes of C-H, Sq. D and Tyco, who have gone to China. But when Siemens went to China to reduce their costs over India, they found that QC was virtually impossible to manage. The samples they got back from the same factories being used by the other competitors were absolute worthless junk.
So if you want a REAL contactor, and one that will not likely make noise like that, I would opt for an IEC contactor. Some of them even specifically offer special coil options that are exceptionally quiet. they cost more than DP, but they will not embarrass you.
A DP contactor is to the electrical control device world what a Yugo is the the Automotive world; a piece of junk that meets the absolute bare minimum requirements to be called functional. I should also point out that if you are in a State that requires NRTL listing of devices, you have violated the requirements by using them, unless you are a UL panel shop and have paid the copious fees for adding them to your procedure. DP contactors are NOT UL listed, they are UR, meaning UL Recognized. The difference is, you cannot install UR devices unless they are a sub component of a larger listed system, and even then, only after UL has thoroughly investigated exactly how your plan to use them.
Secondly, DP contactors, being the CHEAPEST junk that will do the job, are all notoriously noisy, even if clean and brand new. There is virtually no attention to detail in their design, in fact the only design criteria used is manufacturing cost (#1) and as I said, bare minimum functionality.
Thirdly, ALL DP contactors are now made in third world countries such as China and India. The better one's are made in India by the way, but when I worked for Siemens, who's products are made in India, they made a conscious decision to abandon that industry as far as future product development and promotion goes because they can no longer compete with the likes of C-H, Sq. D and Tyco, who have gone to China. But when Siemens went to China to reduce their costs over India, they found that QC was virtually impossible to manage. The samples they got back from the same factories being used by the other competitors were absolute worthless junk.
So if you want a REAL contactor, and one that will not likely make noise like that, I would opt for an IEC contactor. Some of them even specifically offer special coil options that are exceptionally quiet. they cost more than DP, but they will not embarrass you.
buck33k
Senior Member
- Location
- Washington state and North Carolina
Why the name...definite purpose?
I wondered about that too.....
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
"Definite Purpose" means that it is used for a specifically engineered application, where you know every detail about the load; FLA, LRA, duty cycle, mounting, connection method, operating temperature, wire temperature rating AND the expected life span.
For xample, you are an OEM of HVAC equipment and you know that know your chiller compressor is going to come on once every 15 minutes, 12 hours per day 7 days a week and you want the contactor to last beyond the 1 year warranty, but not much more because you want to get the service call to replace it when it wears out. So you look at the fact that you want 17,520 operations, you are switching lets say a 10HP 240V 3 phase motor, so 28A FLC and 154A LRC. Then you look at a chart from the DP contactor mfr. that says that a 30A DP contactor will only last 10,000 operations switching 150A LRC, but a 40A DP contactor will provide 20,000 operations switching an LRC of 180A, so you pick that one. This is why UL will not "List" a DP contactor, they will require that you show them all this information (and more) when you go through the process of adding it you your procedure.
PS, especially for you Besoeker (because I think you are n the UK?). You may notice this is not much different from what you would do to select an IEC contactor. The difference is, the IEC contactor will typically have a minimum mechanical life of 10 million operations and an electrical life of 1 million operations. A DP contactor is not that robust but sells for probably 1/2 the cost or less in volume to OEMs.
For xample, you are an OEM of HVAC equipment and you know that know your chiller compressor is going to come on once every 15 minutes, 12 hours per day 7 days a week and you want the contactor to last beyond the 1 year warranty, but not much more because you want to get the service call to replace it when it wears out. So you look at the fact that you want 17,520 operations, you are switching lets say a 10HP 240V 3 phase motor, so 28A FLC and 154A LRC. Then you look at a chart from the DP contactor mfr. that says that a 30A DP contactor will only last 10,000 operations switching 150A LRC, but a 40A DP contactor will provide 20,000 operations switching an LRC of 180A, so you pick that one. This is why UL will not "List" a DP contactor, they will require that you show them all this information (and more) when you go through the process of adding it you your procedure.
PS, especially for you Besoeker (because I think you are n the UK?). You may notice this is not much different from what you would do to select an IEC contactor. The difference is, the IEC contactor will typically have a minimum mechanical life of 10 million operations and an electrical life of 1 million operations. A DP contactor is not that robust but sells for probably 1/2 the cost or less in volume to OEMs.
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