1. Welcome to our site! Electro Tech is an online community (with over 100,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

power saver circuit

Discussion in 'General Electronics Chat' started by plodhi2002, Aug 27, 2006.

  1. plodhi2002

    plodhi2002 New Member

    Joined:
    Jul 4, 2006
    Messages:
    6
    Likes:
    0
    Could anyone tell me what sort of circuit is used in power savers commonly available on the net by mail order. these can be plugged into home sockets so that you have less usage of electricity especially when you use a/c in summer or fridge and deep freezer. one method i saw on net was to fit a mains capacitor to correct power factor across the motor terminals. Are there any other electronic circuits for reducing voltage to reduce electricity consumption of a/c motors?
  2. Marks256

    Marks256 New Member

    Joined:
    Jul 14, 2006
    Messages:
    2,350
    Likes:
    9
    Location:
    Minnesota, USA
    There is a reason why they take the amount of power they do; SO THEY WORK PROPERLY! :eek: If you try to do something to use less power to them, then you will make them less efficient at the job they should be doing. If you want to cut on A/C costs, get a few fans. They are about $20, and they work awesome. :)
  3. Hero999

    Hero999 Banned

    Joined:
    Apr 6, 2006
    Messages:
    14,901
    Likes:
    75
    Location:
    England
    That's right they are mearly power factor correction devices. Motors and other inductive loads draw a lagging current, all these units do is introduce some capacitance to ballance it an lower the current consumption. They do not actually lower the power consumption of the device itself, they just reduce the current consumption. Power is saved but only because the current is lower hance the R squared I losses are lower.

    These units won't reduce your bill by much as you're most likely billed by the power you use rather than VA. However these power savers are still a good idea since the save losses in the cables and therefore they're good for the enviroment.
  4. sonamoni.ng

    sonamoni.ng New Member

    Joined:
    Apr 8, 2009
    Messages:
    1
    Likes:
    0
    I need a power saver circuit diagram with specification.
  5. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    5,560
    Likes:
    293
    Location:
    Sawyer, North Dakota, USA
    There is actualy a energy saving device called a Watt Wizard or a Green Plug. It slightly varies the voltage going into a inductive load type devices like air condioiners, refrigerators and freezers. It varries the voltage proportinaly to the to the load to keep the internal inductance losses down.
    In some devices the induction motor is running a very light load at times. If the incoming line voltage is dropped to a lower level the total energy loss in the motor goes down. Being able to reduce the line voltage when the load is light will save energy.

    It does actualy reduce the total wattage a device uses but not much. I have had one for about 15 years. I have in fact ran it through an actual spinner type watt meter and found that it does in fact Work! BUT the actual savings is small.
    Its the only energy saving device on the market that I have found that actualy does some small but measurable good!

    For what one costs it would still take years to pay for itself by avoided cost comparison.
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
    Messages:
    29,362
    Likes:
    684
    Location:
    Canada, of course!

    Industry is billed extra if their power factor is poor. A home is not because a home's meter ignores a poor power factor.

    The "energy saving" device is just an over-priced capacitor. Its value might be too high or be too low. It saves money for the electrical utility if its value is correct for your inductive appliances but since the appliances turn off and on then the capacitance is frequently too high so it costs the electrical utility more, not less.
  7. Hero999

    Hero999 Banned

    Joined:
    Apr 6, 2006
    Messages:
    14,901
    Likes:
    75
    Location:
    England
    I would hope that it's an array of capacitors which are connected or disconnected according to the power factor.
  8. JLO

    JLO New Member

    Joined:
    May 27, 2009
    Messages:
    2
    Likes:
    0
    Location:
    Philippines
    I just installed one in my water pump last week, got the power saver from china with brand name 'Power Star'. Upon checking, using a clamp meter, i got 0.4amps reduction which if i multiply with line voltage of 230VAC, i can reduce around 90watts. I hope this can give some savings on the actual bill as well..
  9. Sceadwian

    Sceadwian Banned

    Joined:
    Oct 27, 2006
    Messages:
    14,047
    Likes:
    140
    Location:
    Rochester, US
    And how are you measuring the efficiency of the pump? Reducing current isn't going to increase efficiency if the pump just has to run longer. You can't get something for nothing.
  10. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    5,560
    Likes:
    293
    Location:
    Sawyer, North Dakota, USA
    I suspect its similar in operation to the watt wizard I have. It will save but the realistic savings will not likely ever off set the purchase cost!
    I still watch auctions and garage sales for them though. If you pay under $3 they are cost effective! :D
    For refrigerators, freezers, water pumps, heat pumps, and air conditioners they do work but not as great as they advertise! :(;)

    If you get the chance to buy one used for cheap get it! You can spend more money on worse stuff! :p
  11. JLO

    JLO New Member

    Joined:
    May 27, 2009
    Messages:
    2
    Likes:
    0
    Location:
    Philippines
    Mine was free as a gift from a friend. If you will buy it here, it'll cost you $USD15. About the actual savings i'm not really sure..have to wait for the actual bill.

    For the pump effeciency, i don't have other test aside from above but i think 0.4amps doesn't affect at all (pump rated 1HP)... and yes i agree the product isn't work as advertised... if mine really works.. it only gives around 7~8% reduction.

    Thank you guys for your comment...:)
  12. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    5,560
    Likes:
    293
    Location:
    Sawyer, North Dakota, USA
    Mine was free too!
    The only reason I know they work a little bit is because I am rather skeptical of such devices and I have ran mine through an actual standard spinner type watt hour meter and did time based testing with different electrical devices.

    There was honest power savings but only about 5 - 15% from one device to another. Compressor based cooling devices were typically the highest. Standard induction motor mechanical drive devices were the lowest.
    I think the compressor type devices were only able to save a bit more because of the way the cooling system will interact with a slightly slower running motor.
    Slower compressor speeds make the coolant gas peak pressures lower and thusly further reduces the energy required to pump it.

    Mechanical loads are typically reasonably fixed loads so the only energy savings is from being able to reduce the line voltage going into the motor. That in turn cuts down on internal motor losses. But only slightly.
  13. amitgoel1976

    amitgoel1976 New Member

    Joined:
    Aug 31, 2009
    Messages:
    1
    Likes:
    0
    I need a power saver circuit diagram with specification.
  14. Marks256

    Marks256 New Member

    Joined:
    Jul 14, 2006
    Messages:
    2,350
    Likes:
    9
    Location:
    Minnesota, USA
    lol!!!!!!!! :D
    Last edited: Aug 31, 2009
  15. blueroomelectronics

    blueroomelectronics Well-Known Member

    Joined:
    Jan 21, 2007
    Messages:
    12,432
    Likes:
    159
    Location:
    Toronto, Canada
    I need a power saver circuit diagram with specification

    Why it's so easy to cut and paste. :)
  16. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    5,560
    Likes:
    293
    Location:
    Sawyer, North Dakota, USA
    By the time you build one yourself and run it until it pays for itself in avoided costs on any type of home appliance you will be to old to care. :(

    If its just because it good for the environment, grow up. Go outside and pick up garbage on the streets in your neighborhood and local community and you will get recognition and exercise at the same time and far more personal 'gone green' bragging rights too! Plus the environment will be much further ahead if you do. ;)
    Sorry to be blunt like that but some days it just needs to be done.

    If your really looking to save energy just use less electrically powered stuff or turn it off when your done! :)
  17. blueroomelectronics

    blueroomelectronics Well-Known Member

    Joined:
    Jan 21, 2007
    Messages:
    12,432
    Likes:
    159
    Location:
    Toronto, Canada
    For once we see eye to eye :)
  18. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    5,560
    Likes:
    293
    Location:
    Sawyer, North Dakota, USA
    Just for once? I find what you have to say interesting and informative. You may not like my views and approaches on how to do some things but still I always rate yours pretty well! :)

    Besides I need guys like you to make me think some days! ;):D

    Just dont bust my chops every day. It starts to come off as obsessive and unhealthy at some point. :eek: :p

Share This Page

___...__