Picking up on power

As you watch your turbine on a moment-to-moment basis, seeing the instan-

taneous energy production is fun and interesting. That’s wattage, and I’d love

to have an analog wattmeter, because the device’s dial makes it very easy to

see how the production varies. More often, a wind-energy user has a digital

wattmeter, or you may have analog amp- and voltmeters with which you can

do the math (because volts times amps equals watts). I describe meters in

more detail in Chapters 4 and 6.

A voltmeter that goes before the rectifiers (wild AC to DC conversion devices) is

also a very useful device because it can show you while standing in the power

room that the turbine is spinning. You watch the voltage rise up to about your

battery voltage or at the cut-in of the inverter, after which the machine will

start working for you. This helps you become aware of when the machine is

actually generating and when it’s not spinning fast enough to do its job.

You or your installer establish baseline values for your system early in its opera-

tion. For instance, you may know that the set point at which your inverter starts

to “sell” electricity to the utility is at 56.2 volts, and under normal operation, the

battery voltage will generally be at that level or below. With this information,

you can recognize when something is amiss; if you see the battery voltage at

59.6, you know that either the grid is down or something is wrong with your

inverter or settings. Similarly, being able to monitor your amperage and wind

speed helps you notice small issues before they become big problems.