Contactors getting burnt

[Snapperhead]

https://climate.emerson.com/document...us-2884324.pdf

[timebuilder]

The carbon tracking issue is just an annoyance on a 208 unit. It pops breakers on a 480 unit. The carbon mixes with a little snow that finds its way into that compartment, and BAM, the feeder breaker in the electrical room opens, because it has a shorter rise time.

Replacing the contactors once a year IS excessive. I wait until I get some real pitting on those contacts.

I never replace these with a three pole breaker. When I find one, it means "joey" has been there. JMHO.

[Snapperhead]

Yeah , "joey" has good intentions but doesn't realize the manufacturer uses the 2 pole contactor as a CCH

Or a 1.5 pole in residential .. same idea using CCH

[pecmsg]

3 phase 3 pole
As far as the CCH nothing wrong with running it during cooling. Otherwise a small relay or isolation switch mounted to the contactor works.

[71CHOPS]

so are the contacts burnt and pitted?

[Snapperhead]

so are the contacts burnt and pitted?

post 21 has a picture exactly like this contactor , except add a little black dust around

I was about to purchase 2 of those fancy contactors but read they are Single Pole / W shunt ( they claim it replaces 2 poles as well ) and I guess you "could" replace a 2 pole in residential because they have a spade connector specifically for the CCH on that fancy unit ..... but you couldnt get away with that in 3 phase

[slctech]

I always throw away the single pole and go with a two pole on residential and move both CCH wires across L1 and L2. The cost difference isn't a big deal between a single and double. As for commercial that is a different story, to go from a two to a three poll can sometimes be a substantial jump in cost. I would usually stay with a two pole over upgrading to a three pole for this reason, unless for very specific reason. Also these EURO style contactors I am seeing seem to have some exaggerated ratings, IMO, they have very small contact pads in comparison with your plain old contactor that have a bit more meat in the same rating. And older contactors from the 60's, 70's, and into the 80's were much larger with larger contact pads compared with present day contactor of the same rating. Getting to the point with some of these older contactors that there are no longer contact replacement kits, as I go to replace it, I get a contactor half the size, with smaller lugs, and really garbage in quality when compared to the old.

As for that Emerson SureSwitch, I can't remember the year, maybe 2010 or so, I was at Johnstone and the rep gave me one. Fast forward to this last September, I decided to lay a large cement pad down to cover the embarrasing desert area of the side of my home I gave up trying to grow anything. I had to remove my AC. Not a big deal, only a 20ft line-set and AL finned-Copper tube condenser, so I thought it a breeze to just throw the gauges on, push in the old contactor, suck her on down, valve off, ....EASY PEASY... NOPE, I totally forgot that I installed this mystical box...LMAO, there is NO WAY to think around this damn thing to pump down a system in a conventional way. Ended up wire nutting the LINE and LOADs together and used my main disconnect there...100psi , 90, 80, 70, 60, 50, 40, 30, 20, 15, hurry close suction before in vacuum...10psi..sweet...Pull Disconnect!...whew. As for how the mystical box works and if it is any better and how much more life I will get out of it, I do not know, so I can not give it any ratings other than it works and has been working for a decade. Nothing internal you can look at without breaking it to judge arcing, carbon build up, etc.

[71CHOPS]

ok, if your compressor contactors look like that every year, I would suspect short cycling, but would also tighten all connections back to the main breaker, and verify wiring is good and tight at the comp. terminals.

if wiring is all good, upsize contactor rating, switch to an IEC type, or the type you linked too.....getting a higher amp rated unit would prolly lessen the wear. UNLESS there is an equipment sizing, or other issue causing short cycling.

[Snapperhead]

3 phase 3 pole
As far as the CCH nothing wrong with running it during cooling. Otherwise a small relay or isolation switch mounted to the contactor works.

But when the next guy comes along whos never played Engineeer before and is like WTH ... looks at diagram and gets even more confused

[pecmsg]

But when the next guy comes along whos never played Engineeer before and is like WTH ... looks at diagram and gets even more confused

Agreed it sucks for them but still basic electric! I do make a note on the diagram


theres a guy out here that still cant wire in a relay to prevent the compressor and defrost heaters from running at the same time. Allegedly been doing this for 15 years!

[Snapperhead]

While at it ...lets make it a dependable Mercury Relay !

[thatguy]

I always throw away the single pole and go with a two pole on residential and move both CCH wires across L1 and L2. The cost difference isn't a big deal between a single and double. As for commercial that is a different story, to go from a two to a three poll can sometimes be a substantial jump in cost. I would usually stay with a two pole over upgrading to a three pole for this reason, unless for very specific reason. Also these EURO style contactors I am seeing seem to have some exaggerated ratings, IMO, they have very small contact pads in comparison with your plain old contactor that have a bit more meat in the same rating. And older contactors from the 60's, 70's, and into the 80's were much larger with larger contact pads compared with present day contactor of the same rating. Getting to the point with some of these older contactors that there are no longer contact replacement kits, as I go to replace it, I get a contactor half the size, with smaller lugs, and really garbage in quality when compared to the old.

As for that Emerson SureSwitch, I can't remember the year, maybe 2010 or so, I was at Johnstone and the rep gave me one. Fast forward to this last September, I decided to lay a large cement pad down to cover the embarrasing desert area of the side of my home I gave up trying to grow anything. I had to remove my AC. Not a big deal, only a 20ft line-set and AL finned-Copper tube condenser, so I thought it a breeze to just throw the gauges on, push in the old contactor, suck her on down, valve off, ....EASY PEASY... NOPE, I totally forgot that I installed this mystical box...LMAO, there is NO WAY to think around this damn thing to pump down a system in a conventional way. Ended up wire nutting the LINE and LOADs together and used my main disconnect there...100psi , 90, 80, 70, 60, 50, 40, 30, 20, 15, hurry close suction before in vacuum...10psi..sweet...Pull Disconnect!...whew. As for how the mystical box works and if it is any better and how much more life I will get out of it, I do not know, so I can not give it any ratings other than it works and has been working for a decade. Nothing internal you can look at without breaking it to judge arcing, carbon build up, etc.

What benefit do you see in replacing the single pole contractors with double pole contractors? Seems like it would just cost the customer more in either parts required to install a relay or in energy and slightly less capacity if the CCH is let run continuously.

The Emerson contractor must be a solid state relay. I haven’t looked at the specs that close. Or maybe it’s contacts but they’ve added a snubber to it?

[Snapperhead]

Yeah it has contacts , but they are controlled by electronics somehow to keep them from arcing

[R600a]

What benefit do you see in replacing the single pole contractors with double pole contractors? Seems like it would just cost the customer more in either parts required to install a relay or in energy and slightly less capacity if the CCH is let run continuously.

The Emerson contractor must be a solid state relay. I haven’t looked at the specs that close. Or maybe it’s contacts but they’ve added a snubber to it?

They say it only opens or closes the contacts as the voltage and amperage cross the zero point of the sine wave.

Sent from the Okie state usin Tapatalk

[thatguy]

They say it only opens or closes the contacts as the voltage and amperage cross the zero point of the sine wave.

Sent from the Okie state usin Tapatalk

Ok, I read through the link and didn’t see anything about the zero cross. That would make sense if it was on a centre tap single phase system... I wonder how it would work on a three phase 2 leg system.

[R600a]

Ok, I read through the link and didn’t see anything about the zero cross. That would make sense if it was on a centre tap single phase system... I wonder how it would work on a three phase 2 leg system.

I don't know. That is what they told me at the Copeland scroll technology day. It is a single pole so I don't think you can use it three phase.

Sent from the Okie state usin Tapatalk

[timebuilder]

I have not seen a version of the sure switch for three phase, or even two pole installations.

If you have excessive carbon deposits, I would look at cycles per hour, and limit that in the stat setup.

[Kaes]

Simple. You're using the wrong contactor for the job. Get yourself a AC-3 category contactor with damping resistors. Problem solved.

[Mattmm]

What's the contactor size? 20 and 25s I've found to barely make contact with any spring pressure holding the contacts together, any vibration and suddenly you start getting erratic voltage drops across the contacts, anything 30 or more and this issue seems to go away. I've found this issue with many manufacturers.