[RE-wrenches] Home Brew Frequency Switch

[Maverick Brown [Maverick Solar]]

"I have considered using a drop out contactor to isolate the inverters from
the generator following a loss of line voltage."
 
I suggest that method above as the best. Generators can change frequencies
under load and other conditions, etc. so there would not be such a precise
control.
 
Line voltage coil relays are also cheaper and easier to get as compared to
frequency controls.
 
The voltage drop out contactor might be easier to implement using the KISS
method.
 
Good Luck!
 
Maverick


  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
Sent: Tuesday, March 01, 2011 11:20 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] Home Brew Frequency Switch



Folks, 

I am back on the project where I want to install grid tied inverters
(Enphase) on a feeder located downstream of a generator and ATS.

I have considered using a drop out contactor to isolate the inverters from
the generator following a loss of line voltage.

As an alternative, how well might it work to reset the generator frequency
so that it is outside the inverter range? In this way the inverter would
always see the generator as "bad" energy and therefore would never connect
to the generator, only the utility.

The nominal frequency range for the inverter is 59.3 to 60.5. 

What is the effect on the loads in the household if the generator frequency
is adjusted to say 58 or 62 hertz? Would the higher or lower number be
better? Would this fry everything in the house? I can't see that making a
relatively small change like this would effect the overall impedance such
that a problem with current capacities would be a problem. It seems like the
frequency would be more of a problem for some devices.

Anyone have experience with deliberately adjusting generator frequency away
from 60 hertz as described above? 
  
Mark Frye 
Berkeley Solar Electric Systems 
303 Redbud Way 
Nevada City,  CA 95959 
(530) 401-8024 
 <http://www.berkeleysolar.com> www.berkeleysolar.com  

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