Contactors humming like all get out

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straps

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Just got done installing 3 each 3 pole contactors manuf by DANFOSS model DP030-3b2.
Turned power on all 3 are controlled by a timer Model 101. It is in a av room for temp lighting on the roof of the church (Christmas ) Did it on bldg A no problems mounted 3 in a 12 X12 PVC Box screwed ro a outside wall.

Now we get to main church did the same thing but used a nema 3r 12 x 12 box and they hum like all get out. Shut down disconnected all in and outs still hummed like crazy. Reversed power and neutral stayed the same then disconnected the daisy chain same results. Tried each independently and no matter which they hummed like hell.

Any ideas anybody

Thanks
 
Re: Contactors humming like all get out

sq d contactors hummm too..

buy cutler hammer. they are quiter.
 
Re: Contactors humming like all get out

You probably already did this, but check the voltage to the coils to make sure it isn't low or fluctuating. I might even go so far as to swap a contactor from the PVC box into the metal box to see if it does the same thing. I'd guess it's because they're mounted in a metal box. PVC tends to deaden sound and vibration, whereas the metal enclosure does the opposite. You may have to mount the interior panel on rubber insulators to quiet it down. If you do, make sure the interior panel and the box are bonded together with a jumper to maintain a good ground. Hope this helps.

John
 
Re: Contactors humming like all get out

will try in the am swapping a contactor from the other installation cause my supply house claims it will be several days till they get some new contactors in. By the way I did a no load and gor the same reaction this is not just a small hum it is so loud it almost drowns out the radio.
 
Re: Contactors humming like all get out

straps...if you dont change brand.... the hummm will be here..
try ch.
 
Re: Contactors humming like all get out

Sometimes if the faces of the armature are contaminated or do not mate well when they pull together they will hum. With new contractors this shouldn't happen however an it certainly isn't your job to correct it if it was.
Another thing, noise is relative. If the ambient noise is low a device that makes noise will be more noticeable. In a quiet church it could stand out like a sore thumb.
 
Re: Contactors humming like all get out

primary reason they sell latching contactors..next time check into that possibility..no power on coil=no hummm
 
Re: Contactors humming like all get out

Contactors Humming. One of the main reasons for contactor humming is rust, etc. on the face of the armature. When the contactor coil becomes energized and you rust etc. it will give you a great deal of humming. The very simple solution is to clean the face of the contactor armatures and generally the humming noise will stop.
 
Re: Contactors humming like all get out

swapped the contactors and they can be heard from 25 yards away these are all brand new went to Graingers and bought new ones. Suply house claims 2-4 weeks for replacements went to grainger got a credit ap got the contactors and out in 1 hour. Thanks crew much appreciated

Church of pembroke pines . com :cool:
 
Re: Contactors humming like all get out

The fix is simple. Temp touched on the problem: they hum when the solenoid (armature) doesn't pull tightly to the pole faces. The armature pivots to allow intimate face contact.

(No Clinton-Lewinski jokes, please!)

I have reduced humming 99% by spraying WD-40 where the armature pivots (while de-energized - both coils and supplying circuits!). You probably have to remove a cover to access the pivot.
 
Re: Contactors humming like all get out

Just make sure you do have the power off if you use WD40.

It is very FLAMMABLE! :eek:
 
Re: Contactors humming like all get out

install mechanically held contactors instead of electricially held contactors and you will have no hummmm.
 
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