What would be the type of power inverter that I would need to power a 15 amp, 120 volt AC lawnmower?
I have tried inverters up to 1500 watts with 3000 watts peak voltage but they crap out just as the motor starts spinning. Does this mean that I will need a pure sine wave inverter? I have been using modified sine wave units so far. This shouldn't be that big of a deal, I am only trying to power a large,110 -125 volt motor.
Answer:
As said above 120 volts times 15 amps is 1800 watts. And motors should always be ran on Pure/True sine wave.
See this link for information on the sine wave types.
http://www.oynot.com/inverters.html...
Now to run 1800 watts on a 12 volt battery bank.
1800 watts divided by 12 volts gives you 150 amps in the battery just to run the motor with a minium of twice that much to start it. Then you can only run the battery bank to a 50% rate of discharge to keep from hurting the batteries. You would need 8 T-105 Trojan batteries to keep that motor running for a hour.
How strong are you? Can you drag 8, 70 pound batteries around your yard?
Keep in mind that the house breaker that you are powering that motor on is a 20 amp breaker and your house power is Pure sine wave.
Is it worth it ... Nope it is not. Just drag the cord and be happy. There is no better way.
Motors can draw several times more than their rated running current while starting, you might need 5kW or more peak, actually it would probably be easier to replace the motor with a DC motor and skip the inverter. Battery powered lawnmowers have been marketed in the past, but I don't know if they are still made, I doubt they were very popular (low powered and heavy compared to gasoline power)
"This shouldn't be that big of a deal, I am only trying to power a large,110 -125 volt motor." Starting an induction motor IS a big deal.
120 volts X 15 amps equals 1800 watts. you don't have enough running watts rating using a 1500 watt inverter.
To efficiently power an AC motor, you need an inverter specifically designed for that purpose. They are called variable (or adjustable) frequency drives or VFDs. There are a few models available for specific types of single phase motors. Three phase models dominate the market because they provide much better performance. Most of them are designed for AC input, but some are available for DC input. Since 3-phase motors are usually rated 200 volts or higher, about 300 volts DC would be required.
DC motors are not more powerful than AC motors. About the same performance can be had from either when properly selected for the job. Lawn mowers have probably not been made with powerful DC motors because batteries with sufficient capacity have been too large and heavy. New battery technology may be changing that. It may or may not be possible to design a good battery powered lawn mower that is not too heavy and bulky. If it is possible, either an AC or DC motor may turn out to be the best choice.
Are you sure your inverter is crapping out and not your battery? It takes one heck of a battery to supply 200 amps continuous draw for more than a couple of seconds. We have such an inverter system at our radio station and it uses eight, 100 pound batteries. i know because i replaced them recently. to reduce the current and voltage drop in the battery wiring, it is a 48 volt DC battery system.
The answers post by the user, for information only, FunQA.com does not guarantee the right.
More Questions and Answers: