Monday, October 24, 2011

How to increase the alternator's voltage output?

I need to use an alternator to produce 120 volts?but all a found are only 12 to 14 volts and some with external regulator that can be adjusted to 20 volts?is there any way that I can increase the voltage of the alternator to 120V?? I read that alternator can produce 120 volts by changing things in the regulator or using an external device to do so.How to increase the alternator's voltage output?The regulator normally provides a pulsed DC current to control the output voltage. Many sources claim that setting the field to 12V allows it to go to 120V, for sufficient engine speed. Voltage regulation will be terrible, requiring controlling the engine speed unless you make a feedback circuit. However, most auto alternators are 3 phase, and the frequency will be way high. The guys in this link say something like 300 Hz. Using the 3 phase is a problem, as most small devices are 1 phase. What you could do is rectify the 3 phase (the original diodes are probably not rated high enough voltage) and use devices like universal motors (most light power tools) and incandescent light bulbs, which don't care about frequency. You could also chop the rectified DC with transistors to make 1 phase, but it likely wouldn't be a very good sine wave, and this is basically the back half of an inverter.



Getting an inverter to run off 12V DC or a generator for 120V 1 phase 60 hz. is probably your best bet.

http://www.mikeholt.com/forum/Forum1/HTMHow to increase the alternator's voltage output?An alternator is a AC generator that has a rectifier to change the AC to DC. It also usually has a controller that varies the field current in order to regulate the output voltage. This is usually a solid state comparator that senses the 12v DC output and corrects the field current appropriately.



The alternator is usually 3-phase. This 3-phase voltage could be applied to a transformer to provide the required step-up ratio. However, there may be some problems here. The usual car alternator operates at high, variable RPM which means the frequency of the alternator output would vary depending on the required speed. This changes the requirements for the transformer.



However, if you can set your motor speed to a known RPM, it might be possible. The final RPM for your alternator (not the engine - you may need to change the pulley ratios) would be 3600. This should give a frequency of 60 Hz.



The regulator is another problem. If you do not want to charge a 12v battery, you may need to rectify some of the AC output and use this (via a voltage dropping circuit to the regulator) to control the output voltage.How to increase the alternator's voltage output?10:1 step up transformer before the rectifier?
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