Relay contact ratings. - Page 2

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Re: Relay contact ratings.
Quoted text here. Click to load it

**Quite true.

Quoted text here. Click to load it

**I'm a city boy. I don't see many country products.

Quoted text here. Click to load it

**Might be something to do with the different failure modes of the two
devices.


--
Trevor Wilson
www.rageaudio.com.au

Re: Relay contact ratings.

"Trevor Wilson"

Quoted text here. Click to load it


** Thinking about it -  it is more to do with failure mode in the oven
itself.

If a diode or high voltage cap goes west, or there is an internal short the
HRC fuse in the AC will blow.

The current surge during such events would destroy any low cost triac -  but
not a relay.

Also, a relay provides high isolation from the control PCB to the AC supply.



...  Phil




Re: Relay contact ratings.
Quoted text here. Click to load it

**Good points.

Quoted text here. Click to load it

**All academic now anyway. I've noticed that MOs are starting to employ
SMPS nowadays. I scored a broken, high end model from a neighbour. Lots
of IGBTs, but no relays to be seen. Naturally, the fault lies with the
IGBTs. :-(

--
Trevor Wilson
www.rageaudio.com.au

Re: Relay contact ratings.

Quoted text here. Click to load it

Hey Phil, he's stolen your **'s tag! :)

--

John Devereux

Re: Relay contact ratings.

"John Devereux"
Quoted text here. Click to load it


** Nah  -  he used it before me.




...  Phil

 



Re: Relay contact ratings.

Quoted text here. Click to load it


   You wouldn't say that if you ever see an outlet explode and blow a
hole in the wall, when lightning hit the power line a mile away.  I
have.  The noise was deafening, and scared the hell out of my
grandparents & parents.  It took out all the power on my grandparents
farm, as well.


--
You can't have a sense of humor, if you have no sense.

Re: Relay contact ratings.
On Fri, 09 Dec 2011 10:17:53 -0500, "Michael A. Terrell"

Quoted text here. Click to load it

We have underground utilities here.  Some years ago a lightning strike
at a substation 4 miles away blew out numerous appliances, several
PC's, a TV set, and every light dimmer in the house.
        
                                        ...Jim Thompson
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
We've slightly trimmed the long signature. Click to see the full one.
Re: Relay contact ratings.
On Dec 9, 7:47A0%am, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
Quoted text here. Click to load it

I also have dead microwave and furnace transformers.  After installing
MOVs and FUSEs on the primary, i only have to replace them rather than
transformers.  OEM transformers are ridiculously expensive too.

Re: Relay contact ratings.
On Fri, 9 Dec 2011 08:29:56 -0800 (PST), linnix

Quoted text here. Click to load it

After my event, I installed a full-phase MOV block at the entry
cabinet.
        
                                        ...Jim Thompson
--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
We've slightly trimmed the long signature. Click to see the full one.
Re: Relay contact ratings.
On Dec 9, 8:55A0%am, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
Quoted text here. Click to load it

But i don't need to protect the microwave transformer, which draw
almost 10A.  I put in the MOV and 1A fuse on the 12V controller
transformer.  Next is to drill and mount the fuse externally, which
they should have done in the first place.  I guess they would rather
sell new microwaves then fuses.

Re: Relay contact ratings.
On 9 Dec., 17:55, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
Quoted text here. Click to load it

Be carefull about using MOVs. It wears out over time, from subjected
surges. So when your are not home, it may blow without your knowledge,
and the next time you have a lightning surge it doesn't protect at
all. Better to use Transient Voltage Suppressor, Tranzorbs....

Cheers

Klaus

Re: Relay contact ratings.
Quoted text here. Click to load it

I always have a fuse with the MOV.  If it blow (usually short out), it
will take out the fuse as well.


Re: Relay contact ratings.

Quoted text here. Click to load it
can
Quoted text here. Click to load it
blocks.
Quoted text here. Click to load it


   Not if that fuse turns into a flaming ball of plasma.


--
You can't have a sense of humor, if you have no sense.

Re: Relay contact ratings.
Quoted text here. Click to load it

Properly rated fuse never does that.

Re: Relay contact ratings.
On Thu, 15 Dec 2011 13:48:31 -0800 (PST), linnix

Quoted text here. Click to load it
antennas.
Quoted text here. Click to load it
I can
Quoted text here. Click to load it
was a
Quoted text here. Click to load it
blocks.
Quoted text here. Click to load it
a
Quoted text here. Click to load it
grandparents
Quoted text here. Click to load it
strike
Quoted text here. Click to load it

---
So, when a fuse blows, there's no plasma bridging the gap?

--
JF

Re: Relay contact ratings.
On Thu, 08 Dec 2011 21:28:28 +1100, Sylvia Else

Quoted text here. Click to load it

From your description, it appears that your fridge looks like this:
(View using a fixed-pitch font)

---
                          
MAINS>--+---------------+----------------------------+
We've slightly trimmed the long signature. Click to see the full one.
Re: Relay contact ratings.
Quoted text here. Click to load it
 A0% A0% A0% A0% A0% A0% A0%|
Quoted text here. Click to load it
 A0% A0%|
Quoted text here. Click to load it
 A0% A0%|
Quoted text here. Click to load it
 | A0% A0% A0%O-> |
Quoted text here. Click to load it

It should be long enough to melt the ice and let the water drain off.
It can easily be programmable in a micro, at least during
development.  Perhaps a 5 to 10 minutes range.

Re: Relay contact ratings.
On Sat, 10 Dec 2011 17:19:52 -0800 (PST), linnix



Quoted text here. Click to load it

---
Thanks, but I'd prefer some real numbers from Sylvia so that I can
work up a hardware solution for her.

--
JF

Re: Relay contact ratings.
Quoted text here. Click to load it

You don't like my numbers?  Then go with the number from commerical
defrost timer.

http://www.grainger.com/Grainger/PARAGON-Time-InitiatedTime-Terminated-Defr =
ost-5X454?Pid3D%search

4 minutes to 110 minutes in 2 minutes step.
4 to 12 cycles per day.

I would go with 2 pots + 2 A2D. adjust and time it with a micro.


Re: Relay contact ratings.
On Sun, 11 Dec 2011 16:20:48 -0800 (PST), linnix

Quoted text here. Click to load it

---
I don't care for conjecture, which is all you're offering.
---

Quoted text here. Click to load it
We've slightly trimmed the long signature. Click to see the full one.

Site Timeline