ok guys i really need help on this. Im making a wind generator and i need to get a capacitor that would hold my electrical charge while is been convertet by the inverter to ac so i can power stuff around my house. ive been told that i only need one that range from 1.5 to 12 voltes but i only find that hold 250 vdc and is really cheap thoes that one work or it will burn my inveter?
Originally posted 2009-08-08 06:14:45.
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If i were you, i’d use the AC coming off the wind foil motor to charge batteries and then use the batteries through an inverter circuit to power your AC device. The batteries / inverter will act as a stabilizer as well as a surge protector AND will allow for continuous operation without having to worry about a governer (sp) in high wind conditions and a shutdown circuit in low wind conditions.
As to voltage, the capacitor must be able to handle the peak voltage that your wind generator can ever generate. So if your generator makes a maximum of 250vac RMS (all normal AC volt meters read in RMS), then you will need a capacitor capable of at lesat 250/0.707, or 354 volts DC. Having a higher voltage won’t hurt anything, but it will make them more expensive and bigger.
You didn’t state what your generator’s voltage was.
As to capacitance, a 1-farad capacitor (which is huge, normally they are rated in micro-farads, or millionths (u) of a farad) anyway a 1 Farad capacitor charges (and discharges) at the rate of 1 volt per second at one amp. So likewise, a 1uF capacitor would only take one millionth of a second to charge or discharge by 1 volt under a current of 1 amp.
So your goal is to get your ripple to 10% of full voltage, or less.
But you didn’t state what current your inverter draws (or your generator generates) or what frequency the alternating current produced by your generator will be.
But once you know the frequency and the current, then you can calculate a capacitance (the number of farads) in order to sustain the voltage for the time needed at the current needed.
Let us know what voltage, frequency, and current will be going into your inverter and that will help.
If it’s a 12v generator, you would probably one to get one of those huge giant 1F or bigger 12V capacitors sold to audio buffs who like to buffer their 12v battery so their amps sound better.
The first answer is correct. A capacitor will not work in this application, use a battery instead.
Inverters require a fairly constant voltage to operate, eg, 12 volts ±2 volts, which is what you would get from a 12 volt lead-acid battery. If the voltage went above 14 volts the inverter would be damaged, and if it went below 10 volts it would stop operating.
You will need some electronics between the generator and the battery. How much electronics depends on what efficiency you want.
A simple resistor and diode will be least efficient. A voltage/current regulator is better, but still wastes some power. What is the output from your generator?