Surge Protector on an oven

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4x4dually said:
Indeed. Filtering power on the boards would be the smart thing to do; however, I'd just like OEMs to make a standard double oven that has a temp dial and heats up. If they'd drop all this Wi-Fi horse crap they wouldn't need boards that are so susceptible to everything. I'm currently trying to buy appliance for our new house and everything we like has electronic wiz-bang features in them. Just asking for issues. It needs to heat up. That's it. I don't need to turn it on and off from Arkansas. [/rant]
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What do you have against Arkansas?
 
4x4dually said:
Indeed. Filtering power on the boards would be the smart thing to do; however, I'd just like OEMs to make a standard double oven that has a temp dial and heats up. If they'd drop all this Wi-Fi horse crap they wouldn't need boards that are so susceptible to everything. I'm currently trying to buy appliance for our new house and everything we like has electronic wiz-bang features in them. Just asking for issues. It needs to heat up. That's it. I don't need to turn it on and off from Arkansas. [/rant]
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The problem is that electronics cost less than electro-mechanical devices. Once the electronics are there, adding “wiz-bang” features cost almost nothing additional.
 
4x4dually said:
Indeed. Filtering power on the boards would be the smart thing to do; however, I'd just like OEMs to make a standard double oven that has a temp dial and heats up. If they'd drop all this Wi-Fi horse crap they wouldn't need boards that are so susceptible to everything. I'm currently trying to buy appliance for our new house and everything we like has electronic wiz-bang features in them. Just asking for issues. It needs to heat up. That's it. I don't need to turn it on and off from Arkansas. [/rant]
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What's wrong with Arkansas? Next thing, you won't want to do it from the rest stop near York.
(While you're there the gals, at the SW I-80 restaurant dish up one heck of a malt.)
 
retirede said:
The problem is that electronics cost less than electro-mechanical devices. Once the electronics are there, adding “wiz-bang” features cost almost nothing additional.
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Here-in lies the issue. They cheapen it up with tiny electronics that have zero reliability. I'd pay more if I knew it would last 40 years.
 
drcampbell said:
When ROHS was new, there were a lot of complaints that the new lead-free solders produced inferior results. As often as not, it was actually because the production plants switched to the new solders without changing any of their process parameters. RTFI!
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I'm sure that was true in many places, but they're still trying to get around the problem of tin whisker formation without the use of lead:

https://www.google.com/search?q=roh...EAmAHaA6ABkxSqAQkwLjkuMy4wLjE&sclient=gws-wiz
 
We fight the tin-free lead at work especially when putting ball grid mount FGPAs on PWBs. We have to order ROHS FPGAs then send them back out to have them re-balled with tin solder. Our reflow ovens, albeit as sophisticated as they are, don't produce reliable results when trying to solder RHOS ball grids. Most other components are ROHS but the ball grids still cause us heartache. We have an X-ray machine to see under the components. ROHS solder sucks ballgrids. $.02
 
4x4dually said:
We fight the tin-free lead at work especially when putting ball grid mount FGPAs on PWBs. We have to order ROHS FPGAs then send them back out to have them re-balled with tin solder. Our reflow ovens, albeit as sophisticated as they are, don't produce reliable results when trying to solder RHOS ball grids. Most other components are ROHS but the ball grids still cause us heartache. We have an X-ray machine to see under the components. ROHS solder sucks ballgrids. $.02
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We had migrated to QFN packages because they had less parasitcs for high frequency operation than BGAs, and could be had with a metal flag underneath for better grounding at RF.
The only time we had BGAs re-balled is when we had to remove them from a board and have them put back on an automated production tester like a Teradyne, etc. to identify any IC design or fabrication/process problems.

As far as the board failure problem that the OP mentioned, perhaps the board is being exposed to excessive heat because of a design issue in the oven such as a lack of appropriate ventillation, insulation barriers, etc. This could be exposing the components to an inadvertent accelerated life test (e.g., HTOL, etc.). ;)
 
drcampbell said:
Maybe they already do offer such a thing, in their lines of commercial appliances. Have you looked?
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I did when we remodeled our kitchen. You have to careful with clearance ratings. For example, most commercial gas ranges I looked at required a minimum of 6” on the back and sides.
 
retirede said:
I did when we remodeled our kitchen. You have to careful with clearance ratings. For example, most commercial gas ranges I looked at required a minimum of 6” on the back and sides.
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I would have no problem with that and the much lower price too. Thing is with commercial appliances, you may need a larger or higher pressure gas service which the POCO won't give you, (not a problem with propane) a suitable exhaust hood possibly with Ansul, manufacturers won't warrantee their equipment for residential use or provide service and your homeowners insurance company may drop you.

-Hal
 
hbiss said:
I would have no problem with that and the much lower price too. Thing is with commercial appliances, you may need a larger or higher pressure gas service which the POCO won't give you, (not a problem with propane) a suitable exhaust hood possibly with Ansul, manufacturers won't warrantee their equipment for residential use or provide service and your homeowners insurance company may drop you.

-Hal
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That’s correct - no warranty for residential use.
 
2210228-1131 EDT

Comments on transients.

A typical home is supplied with an electrical 240 V centered tapped energy source from a pole or pad mounted transformer, or two phases from a 208 V wye source providing two 120 V supplies with a common neutral. In the wye system the phase angle between the two sources is 120 degrees. Whereas in the center tapped source the two phases are 180 degree apart.

An MOV transient limiter is a non-linear load that I have previously described for circuit analysis as ---
two series circuits in parallel, each consists of a voltage source ( the threshold point ). and a resistor and diode in series. The voltage source defines the voltage at which this load changes from basically a no load circuit to an incremental load resistor. By changing the direction of the diode between the two circuits we have one that works on positive half cycles and the other on the negative half cycle. Obviously the battery polarity had to change.

The magnetic limiter works differently. If I take a square loop magnetic material and wind a coil around this core, then the volt time integral is a measure of where core saturation occurs. A very fast rising voltage at the input will cause the core to saturate more quickly, but the voltage rise to saturation will be much greater than if the voltage rise rate is slower. So I am not sure the magnetic limiter is any better than the MOV, just somewhat different mechanisms, and different results depending on rate of rise of voltage.

A circuit that would be better is a diode bridge with a SCR load where there is some algorithm that was used to trigger the SCR. This will provide a very low shunt path when triggered.

A good solution for electronic circuits is to provide an MOV at the load input with a preceding moderate series impedance.

.
 
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