Question about relays

[Freep]

This is in a Truck Camper

I installed a 115 volt SPST relay to cut off the converter when the inverter is turned on. It works but instead of a click of the relay I hear a buzz first. I've turned it on and off several times and have noticed that if I turn it on within a second of turning it off I hear the click you would expect from a relay. I have also noticed that the microwave doesn't turn on immediately as if it's not getting the full current yet. The microwave has done this since I installed the inverter.

Questions:

1. Is this going to damage the relay and cause problems?
2. What are my options for stopping this alarming sound?

Below are links to the specific items being used.

Inverter

Relay

 

[gnubie]

It's the design of the inverter. Most high frequency designs are built to comparatively slowly ramp up their output voltage at power on and to also be a bit slow to respond to abrupt changes in load which you may see as incandescent lamps in appliances going a bit dim then brightening back up again when something is turned on and going a bit bright and then returning to normal when something is turned off.

There is no fix for this, it's the way they are.

If the relay is actually closing and opening rapidly rather than it just chattering as the arm partially moves until the voltage from the inverter rises enough that isn't good as you'll be causing high wear on the contacts. The AC input side of the converter, I'm assuming you are switching its AC input, may be damaged by this too as the rapid switching if it is happening can cause high current in capacitors and inductors in any filtering and other areas of the AC side of the converter.

 

[Freep]

It's more like a rising buzz then a click. So I don't think it's opening and closing rapidly. But I can put a meter on it to verify.

Thanks for the comment.

 

[gnubie]

Your inverter has USB power out. You could use the +5 from that to run a relay instead using the AC output. At least in my experience the USB power output is cleanly switched.

 

[Freep]

Your inverter has USB power out. You could use the +5 from that to run a relay instead using the AC output. At least in my experience the USB power output is cleanly switched.

The inverter is probably 15-20 feet from the distribution box where the relay is. I actually used UV protected outdoor romex for the line from the inverter to the distribution box and ended up routing the wire on the outside of the camper because of the difficulties in pulling cable between those locations. I'd probably get rid of the relay and go back to flipping the circuit breaker before I took on the job of running another wire from the battery box to the distribution box.

But it would be a good idea if I had a different configuration.

 

[Bob B]

I would try a time delay relay and see if it works OK. I did a quick check and there are a lot of them available on Amazon. Some with an adjustable delay and some fixed. Something like this https://www.amazon.com/Time-Delay-R...+delay+relay+120vac+30a&qid=1601240175&sr=8-3

 

[grizzzman]

It's more like a rising buzz then a click. So I don't think it's opening and closing rapidly. But I can put a meter on it to verify.

Thanks for the comment.

My bet is it IS rapidly opening and closing.

 

[Zil]

Rapidly opening and closing, repeat, That is "buzzing".