Do these devices actually save money? How much would I save?
Item number: 320066192175
Feedback: 100% Positive
Power Save Device(15000watts)-- Save Energy/Electricity Power Save
Money Save your Bill
Save up to 30% of your bill!!!
Awarded with the Excellent Green Environment-friendly Product of China
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Different PIN types available ( work for worldwide)
12 Months warranty
30 Days money back return policy
Using Power Save Device :
1.Reduce electrical energy 10-30%
Different household appliance can get different reducing rate for
something like Air Conditioner, Refrigerator, Clothes Washer,TV etc.
can get better reducing rate 15-30%. For something like Water Heater,
Microwave Oven, Toaster etc. can reduce at least 10%)
2.Save10-30% of your electricity bill
On 1/1/07 1:29 PM, in article
firstname.lastname@example.org, "Ebike Charlie"
The short answer is NO!
I have always been intrigued by the claims for such devices. Usually, the
devices have been for motor operated appliances such as refrigerators. In
that case, one explanation could involve energy getting fed into the motor
and then getting fed out. That would be a power factor argument that might
have some validity, but I never found any detail.
In this case, I took the trouble to look it up the item on eBay. Again,
there were no details. Some of the appliances that would be helped by the
device were water heaters. It is very difficult for me to see any way
heating water with resistive heating would work with less energy. A heat
pump would help, but that is not what they are selling.
If anyone has any idea what these devices do, I would be curious to find
-- Fermez le Bush
Where can I find a description of what these energy star methods are? Where
can I find out what these "boxes" are alleged to do?
Even if these boxes were effective on motors, there is no way the energy
required for a water heater could be significantly reduced.
-- Fermez le Bush
you would save nothing and lose by the cost of the product. if the product
adds to the load you even use more electricity.
as with all "snake oil" claims it offers miraculous results with no
substance of how it actually works.
other claims made for this device:
"Electricitiy-saving box (esb)
Esb use a state-of-the-art electrical technology to actively monitor and
improve the power factor of your household, office or industrial appliances.
In addition, the intelligent technology optimizes the voltage and current
demands thus reducing the active power / kwh demands and can achieve up to
30% savings on your electricity bill! It also acts as a voltage stabilizer
by storing energy for up to 10 seconds and therefore supplies the load with
constant voltage during momentary power surges. This in turn results in a
longer lifespan of your electrical appliances.
most over voltage protection devices burn up or explode when hit by a 10
seconds of power surge. note that no specifics are given. compare this to
the spec sheet of a reputable companies product
to save power use more efficient products and use them less.
As I understand things, these gadgets just reduce the effective voltage
using a SCR/Triac .
They made the "headlines" around 30 years ago when one of the BIG oil
companies bought a company that had some patents. The usual suspects
claimed that this was an attempt by BIG OIL to keep consumers form saving
Lowering the voltage only "works" in lightly loaded motors such as used in
fans. The circuit "smarts" would lower the voltage to a motor to the point
where the current starts to increase and then back off.
Even at the time the benefits were overstate. With all the "energy saving"
appliances today, I doubt that the box would "save" enough energy to
compensate for the power it consumes. My view was that Exxon was "conned."
Again, the device only can save money when used with under-loaded motors.
It's can't save money on heating appliances.
All these 'energy saving box' are fraud and scams!!!
They consist mainly of a capacitor which improves the
'power factor' in the system. The power factor is the
measurement of the 'leading' or 'lagging of the AC
current versus the AC voltage. The power factor is
only meaningful in AC power system, not on DC like
in a car. In DC, the current and voltage are 'in phase'
and the power factor is 1. Also, in AC system, like in
a house, the power factor is also 1 on all the loads
that are 'passive' like the water heater, the range, etc
because they have no motor, like the washing machine.
When the AC system feeds an electric motor, that motor
is what is called an 'inductive load' and is capable of
reducing the 'power factor' because it forces the current
to run and to lag behind the voltage (the a capacitor
of the black box makes the current run ahead of the voltage!).
So, what benefit a house owner gets by improving the
power factor in his house?? ZERO!! Why? simply because
the electric co does not measure his power factor and
does not penalize him for having a bad one. The electric
co. charges the homeowner only for the "real power".
To obtain the same real power with a bad power factor,
you simply draw a little more current then if you had a
good power factor. (this extra current cost very little to
produce; because it is not real)
Now, for the industrial clients it is a different story, because
they use a lot of big motors and have many inductive loads,
etc. The electric co. must supply the extra current to
compensate for the bad power factor. Therefore, they
charge extra for those clients.
Are the electric co's happy to see the public swindled by
installing those 'energy saving black boxes'?? You BET
they do!!! money from haven !!
Many years ago I was interviewed on TV on this subject.
No, a few of them actually do work. In specific situations. One design
I've worked with uses a phase-controlled triac to vary the voltage applied
to the motor. When the motor is running with no load on it, it reduces the
voltage and improves the power factor close to unity. Then when the load is
suddenly applied, it applies full voltage to the motor.
Capacitors can't change dynamically like that to maintain power factor.
Now, improving power factor on a single 1/2 hp motor doesn't save very much
energy (I^2*R losses *are* reduced when operating at better pf). But a shop
with 40 such motors saw a real savings. Especially since the motors were
unloaded about 70% of the time and only fully loaded the other 30%.
And you probably gave the same bogus explanation then?
The savings for a typical homeowner on one or two motors probably *is*
miniscule. The claims of 10-30% for household motors and 10% for electric
water heaters is bogus.
But pf correction on motors in some applications it can add up to real
Electric co's don't sell these things in the US. Why would they care?
Don't get out much??
I would like more details. I used phase control to reduce voltage for
capacitor charging. In the straight-forward circuits, voltage is reduced by
delaying conduction. That LOWERS power factor.
I can see, from the transformer equivalent circuit of an induction motor,
that magnetizing current gets reduced. On the other hand, I would expect
slip to increase. What do all the harmonics do?
-- Fermez le Bush
For the device in posts by gfretwell and daestrom, the original patent
An article in Maintenance Technology from the company licenced under the
NASA patent is at:
of where the device is justified are fairly limited and not
surprisingly don't justify the claims of the original post. Saving money
on a water heater is pretty funny.
The links provide some additonal info, but not the technical details you
are looking for.
The key is it works for motors that are 'lightly loaded'. Only loaded to a
small fraction (< 1/3) of their rated power. Motors that are so lightly
loaded already have a very poor power factor (lagging) due to the
magnitizing current. Reducing the voltage (well, chopping it with a delayed
phase firing of triac) reduces the magnitizing current losses (something you
can 'get away with' when you don't need to develop full torque).
But most home appliances that have motors in them (such as the
refrigerator), the motor has been sized properly to the load and does not
spend extensive time 'lightly loaded'.
And phase-control will certainly *not* save energy in an electric hot-water
I looked at the two links. The first was totally useless except for the
patent number. The second gave a bit more information.
My impression is that you would like a variable transformer like a Variac to
apply voltage to the motor appropriate to the loading. As the load gets
reduced, that would cause more slip. I guess the key would be to use
semiconductors, especially thyristors, in a way to emulate the Variac.
-- Fermez le Bush