On 6/28/2020 8:53 PM, Cydrome Leader wrote:
bud-- wrote:
On 6/25/2020 11:37 PM, Cydrome Leader wrote:
bud-- wrote:
On 6/17/2020 7:10 AM, Chris Jones wrote:
On 17/06/2020 19:56, Phil Allison wrote:
Cydrome Leader wrote:



=====================
Fox's Mercantile
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.

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.



Scam marketers are likely to say that the lower current directly lowers
the Watts, which is a scam.

Didn't know ohm's law just doens't apply when marketers are involved.
Sorry, but it does.

The lies are the amount of electricty and money you will save.

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.)


As far as I have heard, the scam boxes are just a capacitor permanently
connected across the line

1 - I suspect the capacitors do not change the power factor much, thus
do not change the circuit current much - negligible change = negligible
saving (see 2 for the advantage of lower current)
2 - As in the post above, power factor correction can lower the current,
and thus wasted power in wire resistance, but only in the wiring from
the meter to the scam box. Boxes are likely to be at the service -
negligible length = negligible saving.

The junk ones just plug into an outlet, they don't hard wire into your
sevice panel. Granted, the outlet you pick could be far from your
inductive loads.



3 - Capacitors are likely permanently connected. When the
motor/inductive load is off the capacitor still conducts a current. That
produces wasted power (metered Watts) in the wire resistance.

Wait earlier you said that lower current, lowering watts - "which is a
scam", but now increased current somehow increases power. I'm so lost
here.


I thought it was rather obvious.

You put a capacitor across a circuit. There is a current through the
capacitor. That current does not cause a Wh meter to change.

There is circuit wire resistance in series with the capacitor. That
cause a voltage drop across the resistance. That voltage drop must
necessarily be in phase with the current. That causes power dissipation
(heat) which will register on a Wh meter. This will be true for scam
boxes that leave a capacitor connected (likely all of them).

I think it us unlikely the scam boxes produce significant changes in #1,
#2, #3.

Selling points I have seen have been on the misconception/lie in my
first comment yesterday.

---------------------
I think it is in another post - in industries with lots of big motors
the utility is likely to meter the inductive part of the load in a
kVARh meter (volt-amps reactive). There is a significant VAR 'penalty'
charged by the utility. That makes power factor correction a
real-good-idea. (And the correction is a lot more sophisticated than the
scam boxes.) But, as has been said, there is no power factor penalty for
residential.

I don't have any bull**** power factor devices plugged into my outlets
24/7 with the expectation of getting money back from the power company
every month.

Power factor correction is real, and plain old induction motors are
terribly inefficient, and you'd benefit from properly correcting the
"empty" current they draw. A sub 60% efficient 1/3 hp frame 56 motor isn't
unheard of, and even a high efficiency ones will draw more than 4 amps at
120 volts. You might only save 10 watts of resistive losess, but might
also be able to not trip a breaker or blow a fuse if other items are on
that branch.

The limiting factor on overcurrent protection is likely the starting
current of the motor, which can be about 6x the running amps. For motor
circuits, because of the starting current, the source overcurrent
protection under the NEC can be significantly higher than the wire
"ampacity".

And as someone wrote, for a "continuous" load (over 3 hours) you are
generally limited to using 80% of the overcurrent device rating.

And imagine you have a motor on a branch circuit that draws "too many"
amps. You connect a capacitor on the branch circuit at the panel that
*significantly* corrects the power factor. That does not change the
current on the rest of the circuit to the motor, which has not been
corrected.

If installed correctly it can help. You have to install it by the load.

Same concept as switchable power factgor correction banks installed at a
factory. It has to be near the load to reduce the distace you're pulling
empty current, lowering line voltage and regulation and wasting a bit of
power.
The major reason PF correction capacitors are installed is to avoid the
large 'penalty' charged by utilities for VAR 'use' when the utility
meters for kVARh. That correction can be done by putting PF correction
caps at the service. This is cheaper to install than at motors.

It may or may not be cost effective to put correction at some subpanels
or motor control centers. That has some added, but smaller, advantages.

And it may or may not be cost effective to put correction at motors.
Considerations include
motor size
percent of time motor runs
circuit length
motor use - very-short off time, plugging, jogging

Industrial correction could be split between at some motors and at the
service.

It is not cost effective to put all correction at motors.
I doubt it is cost effective to put correction at motors in a house.

bud-- wrote:
On 6/28/2020 8:53 PM, Cydrome Leader wrote:
bud-- wrote:
On 6/25/2020 11:37 PM, Cydrome Leader wrote:
bud-- wrote:
On 6/17/2020 7:10 AM, Chris Jones wrote:
On 17/06/2020 19:56, Phil Allison wrote:
Cydrome Leader wrote:



=====================
Fox's Mercantile
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.

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.



Scam marketers are likely to say that the lower current directly lowers
the Watts, which is a scam.

Didn't know ohm's law just doens't apply when marketers are involved.
Sorry, but it does.

The lies are the amount of electricty and money you will save.

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.)


As far as I have heard, the scam boxes are just a capacitor permanently
connected across the line

1 - I suspect the capacitors do not change the power factor much, thus
do not change the circuit current much - negligible change = negligible
saving (see 2 for the advantage of lower current)
2 - As in the post above, power factor correction can lower the current,
and thus wasted power in wire resistance, but only in the wiring from
the meter to the scam box. Boxes are likely to be at the service -
negligible length = negligible saving.

The junk ones just plug into an outlet, they don't hard wire into your
sevice panel. Granted, the outlet you pick could be far from your
inductive loads.



3 - Capacitors are likely permanently connected. When the
motor/inductive load is off the capacitor still conducts a current. That
produces wasted power (metered Watts) in the wire resistance.

Wait earlier you said that lower current, lowering watts - "which is a
scam", but now increased current somehow increases power. I'm so lost
here.


I thought it was rather obvious.

You put a capacitor across a circuit. There is a current through the
capacitor. That current does not cause a Wh meter to change.

There is circuit wire resistance in series with the capacitor. That
cause a voltage drop across the resistance. That voltage drop must
necessarily be in phase with the current. That causes power dissipation
(heat) which will register on a Wh meter. This will be true for scam
boxes that leave a capacitor connected (likely all of them).

I think it us unlikely the scam boxes produce significant changes in #1,
#2, #3.

Selling points I have seen have been on the misconception/lie in my
first comment yesterday.

---------------------
I think it is in another post - in industries with lots of big motors
the utility is likely to meter the inductive part of the load in a
kVARh meter (volt-amps reactive). There is a significant VAR 'penalty'
charged by the utility. That makes power factor correction a
real-good-idea. (And the correction is a lot more sophisticated than the
scam boxes.) But, as has been said, there is no power factor penalty for
residential.

I don't have any bull**** power factor devices plugged into my outlets
24/7 with the expectation of getting money back from the power company
every month.

Power factor correction is real, and plain old induction motors are
terribly inefficient, and you'd benefit from properly correcting the
"empty" current they draw. A sub 60% efficient 1/3 hp frame 56 motor isn't
unheard of, and even a high efficiency ones will draw more than 4 amps at
120 volts. You might only save 10 watts of resistive losess, but might
also be able to not trip a breaker or blow a fuse if other items are on
that branch.

The limiting factor on overcurrent protection is likely the starting
current of the motor, which can be about 6x the running amps. For motor
circuits, because of the starting current, the source overcurrent
protection under the NEC can be significantly higher than the wire
"ampacity".

And as someone wrote, for a "continuous" load (over 3 hours) you are
generally limited to using 80% of the overcurrent device rating.

And imagine you have a motor on a branch circuit that draws "too many"
amps. You connect a capacitor on the branch circuit at the panel that
*significantly* corrects the power factor. That does not change the
current on the rest of the circuit to the motor, which has not been
corrected.

If installed correctly it can help. You have to install it by the load.

Same concept as switchable power factgor correction banks installed at a
factory. It has to be near the load to reduce the distace you're pulling
empty current, lowering line voltage and regulation and wasting a bit of
power.
The major reason PF correction capacitors are installed is to avoid the
large 'penalty' charged by utilities for VAR 'use' when the utility
meters for kVARh. That correction can be done by putting PF correction
caps at the service. This is cheaper to install than at motors.

It may or may not be cost effective to put correction at some subpanels
or motor control centers. That has some added, but smaller, advantages.

And it may or may not be cost effective to put correction at motors.
Considerations include
motor size
percent of time motor runs
circuit length
motor use - very-short off time, plugging, jogging

Industrial correction could be split between at some motors and at the
service.

It is not cost effective to put all correction at motors.

Agreed. One larger switchable bank at a plant will be cheaper and cover
more possibilities than trying to connect capacitor banks at all motors.

I doubt it is cost effective to put correction at motors in a house.

Yup. The largest motor I can think of in a house might be the compressor
in a split airconditioning system. Those always have dedicated runs of
power so they're more like an industrial schenario where wiring is run as
needed, dedicated and properly sized to the intended load in the first
place.