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?
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