mercury relay (paragon f 240/aim 9169)

[Firekist]

i'm interested in getting mercury relays, or regular ones if need be, but not at kiln store prices, or kiln store timeframes.. so..

could someone point me to which ones work, or what criteria there are for these things? (both kilns, both types of relay)

thanks!

--seth

[barefoot stash]

This one is 110 the 220 is back a page


http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=7211284&PMT4NO=88795510

[puddletown]

$10.50!! they want 75.00 at AIM.

[barefoot stash]

Yep... I've never used mercury switches in kilns, however I've used these in my aim for years.

[smutboy420]

http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=88795510
IF thats a mercury relay for that price thats a great price.

Tho it don't say it is a mercury type relay and it looks like a mechanical type and not a mercury relay. If so then the price is about right for a regular mechanical relay. witch is not too good of a choice in any kiln that gets used much. Mecanical relays suck the big one even if you over rate them.

[puddletown]

so where is the best place to get mercury relays smutty?

[somewhere]

http://www.mercuryrelays.com

35 amp relay for $35

[Firekist]

normally open? normally closed?
the 2 pole version?.. i don't see all the connection points needed for the 4 220 wires, as well as the 2 "controller" low voltage wires..

... so.. um.. what'll work?

[somewhere]

sorry that was off the hip you will want a 2 pole relay for 220. Your controller most likely switches using 110 volts. The coil on the mdr is energized by the metal strap that connects the two relays. (small brass bar with small screws) your switching wire goes from the controller to the strap on the relay.
This will work:
http://cgi.ebay.com/AEC-DuraKool-Mercury-Displacement-Relay-2035A120AC-NR-/390091930608?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5ad34a7bf0

you can even use a three pole and just use two poles:
http://cgi.ebay.com/MAGNECRAFT-WM35AAA-120A-RELAY-MERCURY-DISPLACEMENT-/220534647516?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3358e3aadc

I think that oven pulls 20amps so 30 amps should work fine.

[somewhere]

normally open. Then when you energize the relay the contacts close and the power goes to the elements.

[smutboy420]

Thats were I have gotten them from in the past,
http://www.mercuryrelays.com <----- prices are higher then last time I ordered from them. It was $35 for a 2 pole 35 amp with 110v coil. I now see thats what there getting for just one pole now.

[elad65]

Here is image of where "control" connectors are located.

Elad

[somewhere]

Thats were I have gotten them from in the past,
http://www.mercuryrelays.com <----- prices are higher then last time I ordered from them. It was $35 for a 2 pole 35 amp with 110v coil. I now see thats what there getting for just one pole now.

I heard mdr's are going up in price across the board. Some states are phasing them out with new environmental laws. Stock up while you can LOL. I have 5 100amp mdr's that are perfect for the redundant kill switch on the furnace. I can't believe what I paid then and what they cost now.

[somewhere]

Here is image of where "control" connectors are located.

Elad

Thankyou. I think I was as clear as mud nothing beats a picture.

[The Bigles]

anyone have any opinions on what the "best" relay is?

Firekist and I have had our f240 down for a while now. I normally have a backup relay but we just got the kiln and hadn't gotten around to it. We have other kilns so we haven't rushed into buying whatever relay we can get the fastest.

I'd like to do the research personally but haven't had time. I want to get the best relays within a semi-reasonable price range.

[smutboy420]

If by best you mean the longest lasting its hands down a mercury displacement relay(MDR) as the top choice for longevity. They don't have normal contacts in them and instead use mercury to make the contact. by sending an electric currant threw the pool of mercury causes it to expand and rising up to touch the contacts.
So they last and last. because there arnt any moving parts except the liquid mercury.
Tho they are large and not as compact as some other types and they need to be mounted in an up right position. Because if you tip them the mercury touches the contacts and it turns its self on.

Some times that can be a draw back. like if in a stand alone controller.

Next best choice is a good Solid state (SSR) Again like an mdr they also have no moving parts or any thing mechanical inside to break or were out. They work by a LED light and a photo resistor. when power is sent to the SSR the LED inside lights up and shines light on the photo resistor. causing the secondary circuit to open.

But they do eventually go. esp if under rated for the amps or ever over heated. BUt when over rated atleast by 30% higher amp rating I have not had problems with them when using good high quality SSRs.

Then the last choice is a regular mechanical contact type relay. witch even if you go much higher on the amperage rating will still last the least out of all 3 types. Every time one of them turns on or off there is an internal ark on the contacts that eventually cause them to wear out and some times weld them selves stuck. not really recommended on any sort of full time use kiln. Maybe OK on a hobby kiln or some thing that only gets used once in awhile. normally I tend to stay away from them. Cause even a good one still sucks. Even if they don't such as bad as others.

[Mecha]

Hey Smutty,

What SSR would you recommend? Do you have a link to a good set? My mechanical relays are making a strange whining sound about 1 out of every 20 clicks and I would like to replace them before they fail.

[earlbacher]

looks like i need another one for my 99ls/d... again....

not sure how to wire up a mercury relay to my aim, so i guess i should go with a SSR... AIM is a pain to work with, so some helpful ideas would be awesome

[Firekist]

for getting a standardish relay, taking your old one to grainger worked well while we had one in town. they even stocked a few for us as backups.

thanks for the replies, the diagram especially should come in handy =) .. have you guys actually used these relays? any endorsements on these?

thanks!

---seth

[somewhere]

SCR phase angle is really the way to go. Your controller has to be set up for it with a 4 to 20 milliamp output. They cost less to run and will outlast any other type of relay. Your elements will last longer and it's less wear on the refractories. Not really much help but if you designing or building new it is the way to go. It will be the standard soon enough.

[2wheeler]

Thank you thread...