My first Auto also had a DC generator, they used a clumsy (by today's standards) means of field regulation done by electro-mechanical means of alternating the field connection from +DC to GND.
Auto Alternators are much more efficient, higher output at low RPM's
Max.

 

https://peavey.com/support/technotes/soundsystems/PWRDIST.pdf
If You talking about split phase, here's an article that shows that for specialized stuff like audio system, computers or movie studio, split-phase 120v(60+60v) is better for electronics than 120v deriving from 3-phase 208v supply , and coming from 3-phase which is "unbalanced", Have You ever met with recommedations like that, is that really significant difference?

 

I think you are referring to someone who is making a dedicated reference to certain audio installations.
Also he is not talking about 'unbalanced 1ph derived from 3ph' but a N.American 120v-0v-120v system unbalance.
At least that is the way I interpreted it.
Max.

 

I think you are referring to someone who is making a dedicated reference to certain audio installations.
Also he is not talking about 'unbalanced 1ph derived from 3ph' but a N.American 120v-0v-120v system unbalance.
At least that is the way I interpreted it.
Max.

It could be true, because I didn't meet with something like this before

 

If You talking about split phase, here's an article that shows that for specialized stuff like audio system, computers or movie studio, split-phase 120v(60+60v) is better for electronics than 120v deriving from 3-phase 208v supply , and coming from 3-phase which is "unbalanced", Have You ever met with recommedations like that, is that really significant difference?

Somewhat off topic but part of my career involved working as a civilian aboard US Aircraft Carriers. Ships power consisted of the 120 Volt 60 Hz, same as standard US receptacles but rather than 120 V Neutral and Ground it was 60 Volts - 60 Volts and the common. So yeah, similar to US entry of 240 Volt split phase it was 120 volt split phase. There were also within the AIMD (Aircraft Intermediate Maintenance Departments) the 400 Hz three phase but till I saw mention of the 120 Volt split phase I had all but forgotten that distribution system. Anyway, it is used on US warship power distribution.

Ron

 

There is also a true two-phase power distribution system. A fried showed me some motors that were used in his shop a long time ago before the upgrade to 3 phase.

 

And what Do You think about the european and american plugs and receptacles, I like american plug pins beacause they have the holes and make possible to connect the wires even without wall socket, european pins are thick, nickeled and round so they are maybe more durable when plug falls on the ground. European wall socket (except british or italian) protrudes from the wall because they incase a little the ground pin (french type) or clips (german type) so it's not aestethic and euro. plugs have plenty big holes, so without plug could dangerous I think. Regards

 

Yeah I think PSCs have additional windings, the split-phase motor could probably not function without capacitor. That is genarally also next thing why in Europe is 3-ph system, to have a torque by motors without additional stuff and minimalize or simplify the work-environment. But again it seems to be no problem in N.America about that

That makes no sense!
Europe has identical 1ph cap-start/cap-run motors for the same reason.
Both EU and N.A. have 1ph and use the identical motors, and when 3ph is present in either location again identical 3ph motors are used.
Max.

 

I got an unplanned lesson in start cap reversible motors yesterday Outside air temperature here around noon was about 93 F (33.8 C) and we had the house set for 70 F (21.1 C). I had been down the basement and did notice as humid as it was there was not much water running out of the system. Then my wife noticed the house seemed to be warming and the air coming from the ducts was not cold. Uh Oh, I hate this part. Walked outside to see my condenser and fan assembly not truing. Motor buzzing loudly and hot to the touch, real hot as it let go real quick. This is a 240 VAC system. Motor cap is 5 uF and the compressor cap is 50 uF using a two in one cap.I took everything apart suffering in the heat and found a close enough motor and two caps. Bought a new motor and caps, got it wired in and it worked but with a 50 - 50 chance my fan was running backwards. Took things apart again, got to the fan, reversed two wires and we were back in business making cold air. Today the house is back to a nice 70 F inside. I am happy and the dogs are real happy. Can't complain as we put that system in about 15 years ago and this has been the first cost. Motor, and the caps all in all about $150 USD and several hours of my time.

Ron

 

Nearly same issue as you, with the compressor humming. I helped to put some parts on Prius that hit a storm drain while visiting. I nearly fainted a few times getting up quick while outside. I took my blood pressure sitting and then just after standing and it majorly dropped. I flunked the tilt-table test long ago. I think it hit 97F yesterday. The house temp was 85 F at 10 pm. it took a while to get stuff cool. Two 90+ degree days w/o AC.
he toilet valve went south too the day before.

 

I like american plug pins beacause they have the holes and make possible to connect the wires even without wall socket

In one of my "kill me quicks", I did just that, at work. We had to open some valves, so I used an outlet strip with individual switches and "stuffed" the wires in the holes for a few days.

In homes the round ground pin is usually set downward. In labs/industrial places up. The idea is if something flat and metal fell on a partially out plug, it would be less likely to short because it would hit the ground first.

US outlets and wall-warts just don't get along when hanging on the wall. I have a Chinese Li-Ion charger that does not follow the US blade specifications and likes to fall out.

I use two Stanley 31500 Power Squids for my network stuff. e.g. server, switches, skype gateway, router, 2 access points, a USB hub etc.
Eventually an automation server and a 24 port POE switch. It made the network much more reliable.
I had a UPS that died and haven't connected it up. The modem used to be on POE and a UPS, but I had other issues.

The last time I painted a bedroom, I put what's called "tamper-proof" outlets. These, keep kids from being able to poke things in the holes. You have to poke stuff in both holes simultaneously. I was painting the room, and this was a room that did not have grounded outlets, so tamper-proof made sense. I also put in a low-voltage box for stuff like telephone and TV, but nothing is wired. The joist holes are drilled. In house phones are going the way of the dinosaur, but we have an older emergency medical alarm system.

The POTS line is mostly used by "4 cordless phones" with an answering machine base. That's backed up by a UPS. The UPS runs a bedroom light too. There are some conventional phones and separate bells around too.
Paging, using the cordless phone, is used a lot now at home. I was unable to hear the page in the laundry room, so I used a baby monitor. The laundry already had a separate bell for POTS. The cordless phone added speaker-phone and touch-tone capability. Touch-tone was necessary before the Internet. I forward calls to my cell for toll phone numbers, s we have the advantage of a better phone with better audio.

 

That makes no sense!
Europe has identical 1ph cap-start/cap-run motors for the same reason.
Both EU and N.A. have 1ph and use the identical motors, and when 3ph is present in either location again identical 3ph motors are used.
Max.

Maybe only in the eastern Europe, which is kind of "industrial region" because of 3-ph (Wye) system everywhere and voltage at level using in N.America only in the industry. And 3-phase motor doesn't need capacitors, but they cannot run on single phase, they could possibly be remake for 1-ph motor 'cause they have three windings, the third winding could be like start capacitor. And of course when it's "Wye" like in Europe, the "Delta" 3-ph motor cannot run on this, need a converter, because by for example 230/400v, on a "Wye" motor winding is 230v, and on a "Delta" motor winding is 400v and the current is probably even 3 times bigger

 

With HVAC systems we are seeing ECM motors. A brief blurb is here: https://www.genteqmotors.com/Products/Aftermarket/Evergreen_IM/

These are apparently designed for retrofit applications. It's internally 3-phase.

The ECM that's used in my firnace is quite sophisticated. It actually can continuously vary the speed and can even measure the static pressure in the ductwork by monitoring current. The thermostat can report, CFM, RPM and static pressure.

When this system is used in a zoning control, bypass damper is not required because it can adapt the speed to static pressure..

Furthermore, it measures the static pressure once a day with all dampers open (if you have zoning) at high speed. This provides reliable means to when it time to replace the filter.

Typical PSC motor is 1/2 HP for the blower for residential heating and colling applications (i.e. gas) (Fused at 15 A @ 120V) . The compressor is higher. The outdoor unit is fused at typically 40 Amps at 240 V. You have to motors: compressor and fan. AC or heat pump use would be great if we had 3 phase residential. In some parts of the US it is available.

==

A three phase motor is a 3 phase motor. They can be deigned to work at 50/60 Hz or both. 50 Hz may cost more.

==

This http://www.apc.com/salestools/SADE-5TNRML/SADE-5TNRML_R1_EN.pdf is an interesting read.

-==

So is this: http://www.popsci.com/diy/article/2009-10/three-phase-power-and-how-get-it

==

This https://www.pnm.com/documents/396023/396191/ESG_no-drawings/5d70c33e-822c-4864-bc34-dbbd2cd9d0a3 is a utility requirements for supplying power. It spells out the utility requirements.

and

http://www.ct.gov/dcs/lib/dcs/offic.../sp_10_electrical_code_requirements_-_4up.pdf

The utility added thos reqquiremnt:

496.
DISCONNECTING MEANS
Where Company service terminates at a privately owned pole or structure and is metered at that point, a disconnecting means should be provided on that same structure by the customer on the load side of the meter
(Examples: farmstead, mobile home, estate and pertinent attached buildings).
If service is furnished at 277/480 Volts or from a
secondary network system, a disconnecting means ahead of the metering must also be provided

This requirement probably was instituted because during a fire, the utility company probably had to pull the meter which only the utility is allowed to do. Now, with smart metering, supposedly, the electric meter itself can disconnect power remotely.

I know where I live, the meter boxes must have the power company sticker on them. You just can't use the same model.

 

With ...

ThankYou so much for these materials

 

The furnace blower motors are facinating. Bad capacitors are typical failure modes in AC systems. A 10 year life as in my case, isn't too bad. The compressor typically has a high temperature cut out, but no manual reset.

I could see that if a fancier over current detection was implemented that required reset and possibly combined with thermal, you would get better longevity. Obviously, a 3-phase compressor and fan would be much better, but not without 3-phase monitoring. You don;t want your 3-phase compressor to run backwards or single phase.

So, here 3 phase is simpler, but it requires more complex monitoring.

Phase reversals happen sometimes when the power company reconnects after a repair. The loss of a phase at my plant did some serious damage, A once in 25 year event.

You can't convince anyone to fix it until it happens once. When you have to spend $10K USD to replace a compressor for a liquid Nitrogen replacement system) withe expensive Freon or a $5,000 roots blower, it matters to spend $1000 for a motor starter and a $120 motor protection gizmo.

I could not convince the powers that be to create controls that would deal with brief loss or power. In one simple system, a turbo-pump, 5 minutes of a power loss is OK. After 5 minutes of a power loss, it too about a day to restart the one machine.

Other machines depended on a position of a valve where some were automated to close. If that valve was open and a failure occurred for more than about 10 minutes, restart took a few days with lots of cleaning.

I liked the Symcom 102 series: http://www.clrwtr.com/SymCom-Three-Phase-Voltage-Monitors.htm with time to trip, voltage selection and time to restart.

 

Here most energy efficient furnaces here are fitted with an ECM motor now in order to comply with the efficiency rating.
Also W.M.'s are fitted with a similar Fischer-Paykel motor.
Max.

 

Here most energy efficient furnaces here are fitted with an ECM motor now in order to comply with the efficiency rating.
Also W.M.'s are fitted with a similar Fischer-Paykel motor.
Max.

ThankYou so much for that, yeah they are really super

 

So, here 3 phase is simpler, but it requires more complex monitoring.
Phase reversals happen sometimes when the power company reconnects after a repair. The loss of a phase at my plant did some serious damage, A once in 25 year event.
I liked the Symcom 102 series: http://www.clrwtr.com/SymCom-Three-Phase-Voltage-Monitors.htm with time to trip, voltage selection and time to restart.

ThankYou very much, Yeah I think that at all, if higher voltage and more phases than it needs more monitoring. But I think that this problem is by low-voltages, when it's about kilovolts, people have like less impact, and it just works, but maybe I'm wrong

 

ThankYou very much, Yeah I think that at all, if higher voltage and more phases than it needs more monitoring. But I think that this problem is by low-voltages, when it's about kilovolts, people have like less impact, and it just works, but maybe I'm wrong

What actually happened, is we lost one of the phases (power company wise). They don't drop all the phases if you loose one,

Motors, depending on what they are used for do different things when they loose a phase and it would also depend if the motor is off at the time.

Most of the motors we lost were around $200.00 USD and were 3 phase 440. They were running exhaust fans. So, they might run somewhat on 2 phases, but get warm.

We lost a motor on a compressor that did the building HVAC pneumatic systems.

And lost a 208 V 3 phase closed loop Liguid Nitrogen replacement system. That compressor was $5,000 USD. The unit runs about $50,000 USD.

We also lost a motor in a specialized vacuum pump called a "roots blower". When the system was upgraded, I added 3 phase protection and used the pump's thermal.

I did replace a mechanical motor starter with a solid state one for another problem, but I wasn't really happy with the options of the solid state one. It's much easier to set up and will do 3 phase protection, BUT it lacked the ability to set a start-up delay, I think.

 

The closest I got to it in residential situation was in the UK installing storage heaters, if several were installed in one home, the service Co request that they be spaced across 3 ph each to the Neutral.
This was because each homes on a street were each fed from 1ph and a neutral in a block of 3 or 4. from a 3ph star transformer.
The next 3 the next phase etc, so it was requested in order to avoid a miss-balance of one phase.
Max.

Europe attaches so much attention to saving material that they don't say "change the cuircit because here's overload" they say "change the......phase....because here's overload". Like I have at home different phase on first floor and different on second floor. Because the low voltage is the only lateral lines to consumers from the medium voltage backbone (sometimes the houses are far from the main electric distribution or even from main roads), the secondary distribution is not based on the high voltage but on the big station-transformer like 300 kilowatts. Sometimes I see the paradoxes like the medium voltage bypasses me or my neighbours, because it goes to tranformer first and than comes back to our houses in low voltage from the distance like 1 kilometer (0,62 miles) or many longer in some areas I think (!) on different poles from concrete. Often the laterals go in two opposite directions from the transformer. In N.America changing phase is only by transformer when it's lose of phase I think, and it's from about one 7,2 kv to another 7,2 kv for example. Is sometimes in N.America the situations or need to save material through increase of voltage like in Europe? Regards