please refresh my memory: what a PFC capacitor does and a re

[Larz]

On 9/23/19 3:11 PM, Ralph Mowery wrote:

In article <f8ydnTnWzv3UjhTAnZ2dnUU7-aednZ2d@giganews.com>, elson@pico-
systems.com says...

Without a Wattmeter, you have no idea what the actual power draw is.
Some of that 2.3 A is reactive current, at 90 degrees to the voltage, and
you are not billed for that. Measuring the current and voltage
separately, you only get the VA (volts * amps) which is NOT the power in
Watts


I never could get it in my head about AC power either. I know how volts
or amps can lead if there is any reactance in the circuit. I have an
inline power meter that shows voltage, current, and power (watts )_ A
heater element will show about the same watts as the voltage times the
courrent. A load with a large transformer in it will show a much
differant V times A than the watt meter. I understand it doing that,
but not how the power company realy charges for the power.

I did all of these AC calculations, but it was at least 20 years ago.
I've mainly worked with DC since that time & I've always found DC a lot
simpler. Speaking of which, I understand there's actually a way to run
these MV bulbs from DC. I wonder if it's like is done with certain
x-ray tubes and just using a diode to convert to DC, or more elaborate?

 

[Phil Allison]

Ralph Mowery wrote:

-----------------------

I understand it doing that,
but not how the power company realy charges for the power.

** They use *wattmeters* that accumulate so becoming "Watt-hour" meters.

Customers get charged for the actual energy used, not merely current over time.

The ones where I live look much like this:

https://en.wikipedia.org/wiki/Kilowatt_hour#/media/File:Hydro_quebec_meter.JPG

The spinning disk will not move unless both current and voltage of the same polarity exist at the same time.


..... Phil

 

[Fox's Mercantile]

On 9/23/19 10:35 PM, Phil Allison wrote:

** They use*wattmeters* that accumulate so becoming
"Watt-hour" meters.

Customers get charged for the actual energy used, not
merely current over time.

The ones where I live look much like this:

https://en.wikipedia.org/wiki/Kilowatt_hour#/media/File:Hydro_quebec_meter.JPG

The spinning disk will not move unless both current and
voltage of the same polarity exist at the same time.

Back in Manhattan Beach, California, while living with a
friend, The house had a single 120 vac feed, not the more
common 120/120 240 vac feed. So his 1 KW Heathkit amplifier
would draw a LOT of current.

I picked up a power company power factor correction
capacitor. Heh, when we put that across the line, the watt
meter would come to a complete halt.

Watt hour meters will read, properly, with an r+j impedance
load. They get confused with an r-j impedance.




--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Phil Allison]

Fox's Mercantile wrote:

----------------------

Phil Allison wrote:

** They use*wattmeters* that accumulate so becoming
"Watt-hour" meters.

Customers get charged for the actual energy used, not
merely current over time.

The ones where I live look much like this:

https://en.wikipedia.org/wiki/Kilowatt_hour#/media/File:Hydro_quebec_meter.JPG

The spinning disk will not move unless both current and
voltage of the same polarity exist at the same time.


Back in Manhattan Beach, California, while living with a
friend, The house had a single 120 vac feed, not the more
common 120/120 240 vac feed. So his 1 KW Heathkit amplifier
would draw a LOT of current.

** Heathkit ? 1kW ??

FYI, there is ZERO phase angle between the V and I drawn by an amplifier.

I picked up a power company power factor correction
capacitor. Heh, when we put that across the line, the watt
meter would come to a complete halt.

Watt hour meters will read, properly, with an r+j impedance
load. They get confused with an r-j impedance.

** Hope that is not some weed induced hallucination form the late 1960s...

The only thought I have that connects is the power company, aware such shenanigans sometime went on, fitted a device to PREVENT the watt-hour meter ever going backwards. Easy enough to do, in the reduction gear chain for eg.

Piss the hell out of greenish coloured folk nowadays, with their roofs covered in acres of PVs.



..... Phil

 

[Fox's Mercantile]

On 9/24/19 7:18 AM, Phil Allison wrote:

** Hope that is not some weed induced hallucination
form the late 1960s...

Nope, never did weed or any other drugs.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[pfjw@aol.com]

There are several Heath amps that put very nearly 1 kw on the outlet. The AA1640 comes right to mind, as it, in mono, makes 800 watts into 4 ohms. circuit losses of 200 watts or so does not seem unlikely.

My Harman Kardon Citation 16 draws close to 12 amps @ 120 VAC at full load, making 1,440 watts. Not that it has ever been driven to that extreme - but it is just possible.

Dynaco 416, Phase Linear 700, Crown CE1000. There are a good many brute-force amps out there, not accounting for quality, just force.

Peter Wieck
Melrose Park, PA

 

[Fox's Mercantile]

On 9/24/19 7:43 AM, pfjw@aol.com wrote:
> There are several Heath amps that put very nearly 1 kw on the outlet.

This was an Amateur Radio RF amplifier.
3.5 to 30 MHz.
SB-200
<http://www.n2ckh.com/FORSALE/AMPLIFIERS/SB200/sb-200_front.gif>


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Ralph Mowery]

In article <f7c85242-eb1c-4e21-b3f2-f187d14ac69e@googlegroups.com>,
pallison49@gmail.com says...

** Heathkit ? 1kW ??

FYI, there is ZERO phase angle between the V and I drawn by an amplifier.

I don't know how accurate it was, but a few years ago I replaced the
tubes in my Sb-200 amp. I wanted to see how efficient the amp was.


I had an el cheepo China meter that showed Volts, amps, watts. The
volts did check with my Fluke meter.

With a bathroom heater the watts and V times A were vey close maybe
because of the very small fan motor. When hooked to my amp and loaded
to 600 to 700 watts RF out the watts and V times A were way off. One
showed maybe 80 to 90 $ different depending on the loading. I took that
to be the inductance of the transformer causing that.

I don't know enough AC theory to explain it if there is not more than a
ZERO phase angle.

 

[Phil Allison]

Ralph Mowery wrote:

---------------------

** Heathkit ? 1kW ??

FYI, there is ZERO phase angle between the V and I drawn by an amplifier.


I don't know how accurate it was, but a few years ago I replaced the
tubes in my Sb-200 amp. I wanted to see how efficient the amp was.

I had an el cheepo China meter that showed Volts, amps, watts. The
volts did check with my Fluke meter.

With a bathroom heater the watts and V times A were vey close maybe
because of the very small fan motor. When hooked to my amp and loaded
to 600 to 700 watts RF out the watts and V times A were way off. One
showed maybe 80 to 90 $ different depending on the loading. I took that
to be the inductance of the transformer causing that.

I don't know enough AC theory to explain it if there is not more than a
ZERO phase angle.

** The PF of general electronic load is about 0.5 to 0.65.

But that has NOTHING to do with transformer inductance ( a myth) or phase angle and cannot be fixed with a capacitor across the supply.

It has everything to do with the current wave be made up of pulses ( at double the supply frequency ) and so not being a sine wave.

The "true rms" value of a pulsed current is higher than a comparable steady sine current.



..... Phil

 

[amdx]

On 9/23/2019 10:11 PM, Phil Allison wrote:

amdx dickhead wrote:

--------------------



Kind of interesting, this website shows an electric motor has a PF of
0.15 with no-load, and 0.7 to 0.85 with a load.

https://www.electricalengineeringtoolbox.com/2016/12/typical-power-factors-for-common.html

---------------------------------------------------

** Fraid the info is so minimal, it's highly misleading.

Motors used in domestic appliances like washers and fridges operate on full or near full load at all times - so have good PFs.

What they might do off load is not important, as it is very rare.

In any case, the current draw and power consumed off load is much lower.



.... Phil

The reference was to the video where he used an unloaded motor.
Then as you say, "current draw and power consumed off load is much
lower". So how often do you run a motor unloaded and is it worth the
cost of PFC.
How often does a factory run a motor unloaded?
Mikek

 

[Ralph Mowery]

In article <16a879a4-381c-4f70-a7c6-12b2ef95c5cd@googlegroups.com>,
pallison49@gmail.com says...

But that has NOTHING to do with transformer inductance ( a myth) or phase angle and cannot be fixed with a capacitor across the supply.

It has everything to do with the current wave be made up of pulses ( at double the supply frequency ) and so not being a sine wave.

The "true rms" value of a pulsed current is higher than a comparable steady sine current.

Ok I can see that , The meters are not really showing what is going on.
I do understand the part about a 'true rms' not being the same as what
most simple meters show when calibrated for a sine wave and not all
kinds of non sine waves.

Just faulty thinking about the inductance of a transformer.

 

[Phil Allison]

Ralph Mowery wrote:

-------------------

But that has NOTHING to do with transformer inductance ( a myth) or phase angle and cannot be fixed with a capacitor across the supply.

It has everything to do with the current wave be made up of pulses ( at double the supply frequency ) and so not being a sine wave.

The "true rms" value of a pulsed current is higher than a comparable steady sine current.




Ok I can see that , The meters are not really showing what is going on.
I do understand the part about a 'true rms' not being the same as what
most simple meters show when calibrated for a sine wave and not all
kinds of non sine waves.

Just faulty thinking about the inductance of a transformer.

** The simple mistake that most folk make is not knowing the definition of VA and hence the meaning of Power Factor.

FYI: VA = rms Voltage times rms Current.

and PF = true power / VA

For example,

a true rms clamp mater allows a sparkie to measure the VA of a load but he would need a "watt-meter" to find the true power.

Plug-in meters that do both cost very little nowadays.


..... Phil

 

[Larz]

Ok, so I picked up a Kuman Electricity Usage Monitor. For anyone not
familiar, it shows KW used, current V and I, some other things like a
cost calculation, etc. I plugged the 175 W mercury lamp into it and
here are the figures I got after letting the system run for 8 hours, 35 min:

1.77 Kwh
209.8 W
0.19 cost
2.018 A
0.84 pfc

So, inputting my Kwh rate beforehand, it's showing ~19 cents per 8 hour
period.

I have no idea if these figures are correct and probably won't until the
electric bill arrives and/or I ever came across a scope. The device had
good ratings and most folks seemed satisfied, which was the main reason
I purchased it.