I have an application where the client wants power to test equipment in a specific room to be de-energized when the door to the space is opened, there are four disconnects that are located just outside the room I thought of either placing a contactor just ahead of the disconnect with door contacts on the door to open the contactors when the door is opened, another thought was to replace the disconnect with a molded case switch with shunt trip coil, the concern is the noise the contactors make everytime they cycle, I have never heard a contactor open and close just curious if they are ?noisy???
Contactor Noise?
- Thread starter Mike01
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gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
110601-1840 EDT
Use a contactor based on SCRs.
How much current at what voltage has to be switched?
Do mechanical contactors make noise on opening and closing? Yes. Is it objectional? That is for you to determine.
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Use a contactor based on SCRs.
How much current at what voltage has to be switched?
Do mechanical contactors make noise on opening and closing? Yes. Is it objectional? That is for you to determine.
.
- Occupation
- Licensed Electrician
At a minimum they make a click as loud as a snap of your fingers. I have heard some that are as loud as a door slamming. Size and type make a difference.
I imagine there are some quiet types that I have never seen. That's not saying much. There is a lot I ain't seen. Curious what some others may add.
I imagine there are some quiet types that I have never seen. That's not saying much. There is a lot I ain't seen. Curious what some others may add.
hillbilly1
Senior Member
- Location
- North Georgia mountains
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- Owner/electrical contractor
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
What is reason for shutting off power? If LOTO procedures need implemented then you will need to have a switch or breaker with locking device anyhow.
ptonsparky
Tom
- Occupation
- EC - retired
Opening a contactor is usually not to noisy, closing them on the other hand can make your wet your pants depending on how large, old and close you are.
Put the contactor wherever the disconnects are fed from. Most likely a remote room. Consider putting a handle interlock on the safety switches to open the contactors as well. "Late make early break" interlocks will save electrical wear on the disconnects.
Put the contactor wherever the disconnects are fed from. Most likely a remote room. Consider putting a handle interlock on the safety switches to open the contactors as well. "Late make early break" interlocks will save electrical wear on the disconnects.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
110602-0537 EDT
ptonsparky:
What is a "Late make early break" interlock?
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ptonsparky:
What is a "Late make early break" interlock?
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ptonsparky
Tom
- Occupation
- EC - retired
It attaches to the handle mechanism on a safety switch and as you pull the handle down it "opens" before the knife blades. A starter, vfd, or contactor would then open before the blades disengage. When closing the safety switch the reverse would happen. The SS blades would make before the interlock contacts. It could very well be that all handle interlocks are that way by default and I am wasting my breath when I order. Don't know.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I seriously doubt the noise of a 60A contactor opening and closing is going to bother anyone. The door closing will likely make more noise and from the description, would likely happen at the same time, so I doubt they will notice.
Similar vein: I helped on a project for one of the big new hotels in Vegas, every room has a 4P contactor in a box on the inside wall next to the first light switch, tied to an occupancy sensor so that when nobody is in the room, the lights go off. The problem was guests complained about the noise. Turned out that when they were in the room, the contactor was energized and the coil hum ended up getting amplified by the wall. I seriously doubt very many of them heard it, but then again there is probably a higher percentage of hangovers among guests in Vegas. We put rubber grommets under the mounting screws but it still conducted through the screws. We ended up experimenting with various little 20A contactors until we found one that was quiet enough. 3000 contactors...what a royal PITA!
Similar vein: I helped on a project for one of the big new hotels in Vegas, every room has a 4P contactor in a box on the inside wall next to the first light switch, tied to an occupancy sensor so that when nobody is in the room, the lights go off. The problem was guests complained about the noise. Turned out that when they were in the room, the contactor was energized and the coil hum ended up getting amplified by the wall. I seriously doubt very many of them heard it, but then again there is probably a higher percentage of hangovers among guests in Vegas. We put rubber grommets under the mounting screws but it still conducted through the screws. We ended up experimenting with various little 20A contactors until we found one that was quiet enough. 3000 contactors...what a royal PITA!
Last edited:
justdavemamm
Senior Member
- Location
- Rochester NY
Many aren't so you aren't.
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