sci.electronics.repair@googlegroups.com

Google Groups

Phil Allison <pallison49@gmail.com>: Jun 16 03:38PM -0700 Fox's Mercantile bullshitted:   ======================== > +R(ohms) +J(inductance). If they see +R -J they will slow > down or run backwards if the capacitance across the line > (on the load side) is high enough.   ** That is not true.   Wattmeters measure power regardless of phase angle.     > But, capacitors big enough to accomplish that are the size > of a 5 gallon Jerry can.   ** Bollocks.   A 150uF cap draws 11 amps rms from a 240V 50Hz outlet. A polypropylene, 250VAC rated cap of that value would be the size of a large coffee jar.   Problem with such cap on the AC supply is you cannot switch it on - the massive inrush surge will trip a 16 amp thermal magnetic breaker.     ..... Phil

Chris Jones <lugnut808@spam.yahoo.com>: Jun 17 11:32AM +1000 On 17/06/2020 08:38, Phil Allison wrote: >> (on the load side) is high enough.   > ** That is not true.   > Wattmeters measure power regardless of phase angle.   True, however some recent meters use Rogowski coils, where the analogue to digital converter receives a signal that is proportional to the rate of change of current, which is then integrated in digital computation to get the current waveform. The thing the meter designers did not guard against is very sharp steps or spikes in current, leading to a very high output from the Rogowski coil, that can rail the ADC, which then gives a wrong current waveform.   There was a paper a few years ago where some dutch researchers showed a load consisting of some compact fluorescent lamps connected to a dimmer could produce power readings many times higher than the true power consumption, when measured with some meters based on Rogowski coils.   If I recall correctly, the electricity retailers dismissed it as an unrepresentative situation unlikely to occur in real use and did not want to do anything about it.   In my opinion the researchers made a simple error. They should have found a different load that drew a spike of current at a different phase relative to the mains voltage waveform, to rail the ADC at a different time, such that the power reading would be artificially low, or even negative. If they had demonstrated artificially low rather than artificially high readings in their paper, then the meters would have been redesigned and replaced as a matter of urgency.   Whilst a contrived load that causes the meter reading to be artificially low (by drawing a spike of current and railing the current ADC at the right time) may be illegal to sell, if nothing else due to it failing conducted EMC regulations, I suspect that there may still be a significant informal market for such a device.

Fox's Mercantile <jdangus@att.net>: Jun 16 08:03PM -0500 On 6/16/20 5:38 PM, Phil Allison wrote: > Wattmeters measure power regardless of phase angle.   Sigh...   Watt meters work because of a 90 degree phase shift between the voltage coil and the current coil.   Changing the amount of phase shift between them changes the speed at which the dial rotates.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Phil Allison <pallison49@gmail.com>: Jun 16 10:07PM -0700 Fox's Mercantile is such a boring fuckwit wrote:   ----------------------------------------- Phil Allison wrote: > the voltage coil and the current coil.   > Changing the amount of phase shift between them changes the > speed at which the dial rotates.   ** It makes it less and less.   A purely capacitive (or inductive) load produces NO movement of the disk.   Please FOAD dickwad.

Cydrome Leader <presence@MUNGEpanix.com>: Jun 17 07:03AM > the voltage coil and the current coil.   > Changing the amount of phase shift between them changes the > speed at which the dial rotates.   which is a measure of the actual power being consumed, as designed.   You are not going to fool a spinning disc power meter unless you tamper with it.   Power factor correction might lower your power consumption, but this is not going to be a concern in a house, unless you leave terribly inefficient things like 1/3rd horepower induction motors running all day long.

Phil Allison <pallison49@gmail.com>: Jun 17 02:56AM -0700 Cydrome Leader wrote:       =====================   > which is a measure of the actual power being consumed, as designed.   > You are not going to fool a spinning disc power meter unless you tamper > with it.     ** Yep.   > Power factor correction might lower your power consumption,     ** Oops, no it don't.   It simply lowers you RMS current draw.   VERY worthwhile in situations were you are running out of amp capacity for the installed circuits.     ..... Phil

Chris Jones <lugnut808@spam.yahoo.com>: Jun 17 11:10PM +1000 On 17/06/2020 19:56, Phil Allison wrote:   > ** Yep.   >> Power factor correction might lower your power consumption,   > ** Oops, no it don't.   It could lower the wasted power in the resistance of the cable between the meter and the reactive load. This is unlikely to be significant unless you have a very very long cable from the meter to the reactive load. (It will also lower the wasted power in the cables before the meter but since you don't pay for that, there is no financial incentive for the consumer to fix it.)

Tim R <timothy42b@aol.com>: Jun 17 07:45AM -0700 I checked some household appliances (lamps, tv, laptops) with one of those Kill-a-Watt meters some time back.   They register both watts and power factor. Power factor was often very low, in the .6 range. CFLs and LEDs were both very low.   Does that affect the accuracy of the watt reading?   If I understand correctly, I pay for actual watts, but wire capacity has to include the extra. Presumably code requires sufficient headroom.   Kill-a-Watt meters are designed badly, unless they've improved them recently. With bifocals you can only read them in one orientation and often that is not how you plug them in.

Fox's Mercantile <jdangus@att.net>: Jun 17 09:59AM -0500 On 6/17/20 9:45 AM, Tim R wrote: > improved them recently. With bifocals you can only read > them in one orientation and often that is not how you > plug them in.   I hate to be Captain Obvious here, but that's what short extension cords are for.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Cydrome Leader <presence@MUNGEpanix.com>: Jun 17 05:31AM > the game is up! Especially if there really isnt much in the filter area > and I can move the impeller between quadrants, indicating that no > BLOCKAGE is stopping the impeller from moving.   I admit to not fixing dish washers. I do deal with other machinery with similar sized centrifugal pumps. Blockage seems to be the #1 problem. It doesn't really take much to stop a small pump either. All it takes is a piece of cellophane or tape to really mess things up. Complete blockage isn't needed. I've fished out junk with wires and it's not uncommonon to have to completely disassemble the wet side of even primo ceramic shaft, magnetic drive Iwaki pumps to fish out trash in system.   The motor spinning at all is a good sign though. Seized motors burn out real fast, and a burned out motor doesn't usually buzz or do anything.   Can you remove the pump and check the entire path the water takes?

Cydrome Leader <presence@MUNGEpanix.com>: Jun 17 05:49AM > will not last very long at all. That is not the fault of the device, but > of the user not understanding their obligations towards achieve that > efficiency.   I call bullshit on this. While folks on usenet, in a repair group can probably figure out preventative maintenance it's not listed in any consumer product manual. There's no way LG user manual mentions anything other than don't run a pump dry and contact a service professional for anything else. modern appliances are pure junk, plain and simple. My favorite is clogged codensate lines on fridges, moldy side load washing machines and the $400 parts and labor "computer board" for anything else.   1) it's a tube, operated by gravity. Manufacturers somehow mess this up, it has to be on purpose.   2) wow, a big old V shaped gasket might trap water. Sure, I'll run two loads, the second with vinegar or bleach to keep the machine from rotting. Really saves water now, right?   There really isn't much maintenance the end user can perform on appliances these days.   Remember when the only thing to go out on a stove was the oven light and hot element ignitor, maybe once every 10 years? I've seen multiple stove failures that resulted in the entire unit being scrapped due to electronic problems. It's rediculous. Stoves don't need maintenance, don't have pumps and still fail at a very high rate due to unnecessary electronics and awful design practives what serve to only rip off the consumer.

"pfjw@aol.com" <peterwieck33@gmail.com>: Jun 17 05:20AM -0700 Warning: This is a bit of a rant....   I would not accuse you of being a Luddite, but I do question your understanding of basic care-and-feeding of appliances. You admit to doing tear-down maintenance of a microwave oven (surely not in any operations manual), yet will not admit to the most basic understanding of the car-and-feeding of other, larger appliances.   Sure, our range has as much computing power as the Space Shuttle ((but so did the Commodore VIC20), and as such probably should be on a circuit protected by a surge-suppressor (and it is). It is now 12 years old and doing fine. The oven gets used very nearly every day, so it does need cleaning (maintenance), and every so often, beyond just the self-clean feature - and that is not in any manual either.   As to the clothes washer - cleaning the sump quarterly is no big deal, is it? If the alternative is replacing the pump, probably annually (with heavy use)? Now:   a) The typical old-style top-loader used between 35 and 45 gallons of water per full load. The average washer is used 400 times per year (family of four(4)). Splitting the difference, that is 16,000 gallons of water per year. That is 44 gallons per day, just for washing clothes. Which is, typically, also heated at least in part. b) The typical old-style top-loader leaves between one and two gallons of water behind in a full load. Which must be dried, either mechanically or on a clothes line. How many here use a clothes line? For everything? c) Our LG uses five (5) gallons of water on the heavy-duty cycle, and seven (7) if we use a pre-rinse (never needed to, at least so far). Giving it a 8:1 advantage over the top-loader. and a 3:1 advantage over even the most efficient modern top-loader. Making that occasional vinegar douche not so horrible - well, we use chlorine bleach often enough that the vinegar is rarely needed.   At our summer house, where we both make and dispose of our water on-site, and we are on a Class A trout-stream, water consumption is a huge factor. Just below functionality, but above first-cost and even maintenance - although so far, that has been minimal. We are also exceedingly careful of the materials we use such as soaps and detergents.   (Definition of Class A Waters: Streams that support a population of naturally produced trout of sufficient size and abundance to support a long-term and rewarding sport fishery. Management: Natural reproduction, wild populations with no stocking)   And learning what works over the last 30 years upstate has translated into choices we make "at home" to keep to a more gentle footprint - OK, not the "American Way" but so what?   It is a matter of choices made. But it does gripe me when individuals blame the object rather than the caretaker of that object for its failure after years of negligence.   Peter Wieck Melrose Park, PA

Clifford Heath <no.spam@please.net>: Jun 17 11:57AM +1000 On 15/6/20 6:30 pm, Cydrome Leader wrote: >> Melrose Park, PA   > What is the reliability difference, if any between the classic > transfomer/diode/capacitors and the fancy inverter ovens?   We have a National (Panasonic) microwave from 1981, still working a treat. I know of others like it. It's pretty hard to compare MTBF when you have zero F.

Cydrome Leader <presence@MUNGEpanix.com>: Jun 17 06:41AM > the time 0% for 50% of the time. Inverter-based microwaves become far > more flexible and therefore far more useful.   > Re Reliability: Our present Panasonic (inverter) is about 6 years old   well, panasonic does make a decent microwave oven, so this is probably the cadillac of anything with an inverter in it. I have a hand me down inverter panasonic. Seems to work fine, I just use the quick minute button for anything but defrosting stuff. I still have no idea what a baked potato button is supposed to do or why I'd want a power level of 2/10 or anything goofy like that. My favorite interface was on the Tappan ovens with a timer with two timing ranges, a cook/defrost switch and start and stop buttons. The design was pure genius, and hasn't been surpassed to this day. I also keep a 1981 samsung microwave in the museum. It has a whopping 20 screws just to keep the plastic window and shield in the door. No way any part on a $89 medea special will mechanically outlast this thing.   > enough air circulation, and, heaven forfend, even clean the vents > regularly!   > Basic care-and-feeding is becoming a lost art.   I do the open up and deep clean and oil fan bearings every so many years, but this is not something a normal consumer could or should do. BWT, the fans in modern robo-build microwaves are truly puny garbage. I bent she shaft of one just trying to remove the fan blades. No joke. They're really engineered the quality out of these things.

Cydrome Leader <presence@MUNGEpanix.com>: Jun 17 06:55AM > making it 15 years old. It works as well today as it did in 2005 with > no change in output level. That's one of the benefits of an inverter > oven.   Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word.   > fire. If you bought a replacement board, you've probably spend more > on the repair than the oven is worth. I suggest you cut your losses > and just buy a new oven.   I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with.

bje@ripco.com: Jun 17 11:34AM > Lol, I've wondered about the "sensor" in these things. I know can't be > related to any sort of device that measures anything. Must be marketing > speak or a weirdly translated word.   I don't think the "sensor" is a gimmick.   From what I ran across somewhere, it's like a humidity or moisture measurement and really did/does work. I just had a 16~17 year old GE over-the-range type that went out that used sensor cooking and now using a $99 counter top model (1250W Magic Chef) that doesn't, I miss it.   I would of replaced the GE with a current model but it's a 2 man job and with ye old pandemic, I figured the $99 special will suffice for now until an assistant is found. What's odd with the break down is the keypad doesn't work and it's not the keypad or ribbon cable.   About a month before I noticed the 3-6-9 buttons wouldn't do anything but all the others were fine. Then one early morning, ComEd (local power company) cut the power for about 10 minutes which reset the clock back to the blinking 12 (actually I think it scrolls "Press clock to set time") and that was that. No more workie. It does boot, plug it in, you get the beep and even the "GE brings great things to life" scrolls on the display.   Everywhere I checked for parts (figured a new/used control panel) ended up the same "Not in stock - No Longer Available".   Disappointing.   -bruce bje@ripco.com

John Keiser <johnkeiser@juno.com>: Jun 16 07:23AM -1000 On 6/16/2020 6:19 AM, root wrote: > I was looking through an old copy of Seely's book. My favorite tube > (on the basis of clever design) was the Phantastron. Really slick.   Is this what you want?   http://gen.lib.rus.ec/book/index.php?md5=9A1210D3901B37ED01DC4F2246A395D0

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.