Contactor that doesn't hum?

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jaggedben said:
So just to be clear, for everyone recommending the RIBs, you've had no problems with hum on the non-latching relays?

Thanks for all the replies.
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I use them all the time. They don't hum. They're just little 5vdc cube relays inside. They have internal PCB that gives them a nice range of coil voltages making them very universal. The relays inside are quite robust and go on for years and thousands of cycles.

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BTW, RIB also makes 3-wire mechanically latching relays for lightning.

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Terminator5047 said:
Grainger is a rip off as we all know try to order some place else but the company function devices has a ton of useful stuff such as ribs and powe lt supplies you should check out their product line
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hillbilly1 said:
Yes, they are much higher, but unlike regular supply houses, they have it in stock if you need it right now. If you have time to wait though, it is much cheaper elsewhere.
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Zoro ( a division of Grainger) is cheaper if you don't need it the same day. For example, the RIB below is $12 cheaper at Zoro.

https://www.zoro.com/functional-dev...300vac-dpdt-rib24p/i/G0682507/#specifications

I find their category "Functional Devices" somewhat amusing. I wonder if they carry non-functional devices. ;)
 
I would like to report to you all that the 20A RIB worked great for this application. Thanks to all who recommended it. (Btw, we first tried putting some rubber washers between the Eaton contactor and the can, and that did not help.)

I do still have a follow-up question. The RIB product line only goes up to 30A. Anybody have a similar recommendation for a 40A circuit?
 
I have been known to spec them when I want the EC to supply a dry contact for some reason. To be honest, I don't know if the EC actually used a RIB or not. They might have just used a regular relay. Other than being able to use the same device for multiple coil voltages, there is not a lot of dofference.
 
jaggedben said:
I would like to report to you all that the 20A RIB worked great for this application. Thanks to all who recommended it. (Btw, we first tried putting some rubber washers between the Eaton contactor and the can, and that did not help.)

I do still have a follow-up question. The RIB product line only goes up to 30A. Anybody have a similar recommendation for a 40A circuit?
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Use a 24VDC-coil contactor, and power it with a 24VDC power supply. Switch the 24VDC power to the coil using a small icecube relay with the coil voltage of your choice. DC-coil contactors will not hum like AC contactors will. Note: it's not a good idea to switch AC power to the power supply, especially if the contactor switches often; you'll likely kill the power supply.

We specifically use DC-coil contactors in TV studio automation applications because they're silent once they switch.


SceneryDriver
 
jaggedben said:
I do still have a follow-up question. The RIB product line only goes up to 30A. Anybody have a similar recommendation for a 40A circuit?
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If you wire two 30a contacts in series (not parallel), they should handle switching 40a.

Is there a 2-pole 30a RIB available?
 
SceneryDriver said:
Use a 24VDC-coil contactor, and power it with a 24VDC power supply. Switch the 24VDC power to the coil using a small icecube relay with the coil voltage of your choice. DC-coil contactors will not hum like AC contactors will. Note: it's not a good idea to switch AC power to the power supply, especially if the contactor switches often; you'll likely kill the power supply.

We specifically use DC-coil contactors in TV studio automation applications because they're silent once they switch.


SceneryDriver
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I don't like the extra steps so much, but perhaps more importantly can you suggest an 40A rated 24VDC coil contactor for under $50?
 
LarryFine said:
If you wire two 30a contacts in series (not parallel), they should handle switching 40a.

Is there a 2-pole 30a RIB available?
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That would not (or shouldn't) pass an inspection. It's also a terrible idea. That's how you get burned up components; it's not just the switching arc, it's the ohmic heating that contacts see. 40A through a 30A contactor is a good way to start a fire. Would you try to pull 30A through a pair of 20A receptacles if they were in series?


SceneryDriver
 
SceneryDriver said:
That would not (or shouldn't) pass an inspection. It's also a terrible idea. That's how you get burned up components; it's not just the switching arc, it's the ohmic heating that contacts see. 40A through a 30A contactor is a good way to start a fire. Would you try to pull 30A through a pair of 20A receptacles if they were in series?
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Not the same thing.
 
What you are showing is a 40 amp motor rating. Most size 0 IEC contactors are rated for 40 amps resistive which is what the rib relay is rated for. You can get size 0 IEC contactors for 20 bucks or thereabouts
 
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