Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Heavy Load Motor-Generator (Dynamotor) Questions

  1. Jul 19, 2011 #1
    The motor-generator will be used to pull a load up a mountain side/steep incline on a rail system, the load is between 10 and 300 tonnes, its for a gravitational potential energy storage system. Excess electricity pulls the load up the incline, when there is demand for electricity the load is released driving the generator. Obviously a good gearing system is required.

    Is this technically possible? How much do you estimate one would cost? What would be the device's efficiency?
     
  2. jcsd
  3. Jul 19, 2011 #2

    russ_watters

    User Avatar

    Staff: Mentor

    Welcome to PF! Absolutely, it is technically possible. It's a relatively straightforward means of storing energy.
    There's a big difference between 10 and 300 tonnes and a bunch of different ways of doing it, so it's pretty hard to just pull a cost estimate out of the air. Expensive, though, since you have to build a structure that can support your chosen mass.
    Motors and generators are both pretty efficient, so depending on how serious of an estimate you need, start with 95% each, off the top of my head. Then take another 20% off for drive losses. So you might be able to see around an overall 70-75% efficiency.

    I'm not sure where you're going with your question, but if you're trying to think if this would be a viable means of energy storage either for a home or on an industrial scale - probably not. The main reason is that lifting a big weight stores less energy than most people realize, which means that storing a useful amount of energy costs a lot more than people realize. That's why pumped water is more often used - if the geology is right, you don't even have to build a tank for it!
     
  4. Jul 19, 2011 #3
    I've been searching for a suitable motor-generator (Dynamotor), but the largest I have found is a mere 2 HP! Does anyone know of any manufacturers that produce larger ones?

    The system would be used in a small remote community (with suitable topography) to store energy generated by an intermittant renewable source.
     
  5. Jul 19, 2011 #4

    russ_watters

    User Avatar

    Staff: Mentor

    Did you calculate how big of a mass you need and how far you need to lift it to store the capacity you want?
     
  6. Jul 20, 2011 #5
    Initially 300 tonnes, raised through 500 metres, not accounting for transmission losses I got 409 kWh, which is quite alot, so the load could be reduced some what. I'm more interested in the motor-generator though, whether ones exist that could be applied to this problem and if so how much they cost.
     
  7. Jul 20, 2011 #6

    russ_watters

    User Avatar

    Staff: Mentor

    Wow, that's quite a mass and quite a height.

    So are you looking for a motor/generator more on the order of 100 kW? I think you may need to find a manufacturer for a dedicated product, but it is my understanding that an ac induction motor can be used as a generator.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Heavy Load Motor-Generator (Dynamotor) Questions
  1. Motor generator (Replies: 2)

Loading...