Two Classics, one turbine

[kitestrings]

Hi Folks,

Been awhile since I've gotten back here.  A couple questions:

We're slowly closing in the build of a 15' axial turbine.  We purchased two Classic 250's and we're planning to connect them in similar fashion to what Ryan had done with his neighbor's.  We've built a rectifier box with isolated outputs for each unit as recommended.  Not up to date, but described here:
http://midniteforum.com/index.php?topic=325.0

Wondered if anything had changed.  There was some discussion about having the controllers be able to parallel with one another (i.e. split the load, as opposed to having one load up, then pass to the second/slave).

The clippers were not available when we started this project, and I prefer the stud-mount diodes, but is it possible to use the MS (4 kW) clipper without the potted bridge? Or maybe it is a slightly different question...  Is it possible to get dump load box from MS, but use the rectifier, breakers and relays that we already have?

Thanks for any advise.  ~kitestrings

[TomW]

kitestrings;

Not sure if this helps but you can feed DC into a Clipper. Probably still need the bridge to isolate the classic input from the shorting switch? I feed DC to mine and it has the bridge in the circuit.

Classics do not like having the input shorted. Seems a simple suitably rated diode is all it would need to accomplish that.

I am sure one of the Midnite guys will get back to you on this.

Tom

[kitestrings]

Thanks Tom,

Right now we've got two SS relays mounted in the rectifier box.  This box also houses the heatsinks, DC breakers, an rpm gauge for the trurbine and an Omron voltage/limit control.  Here's the logic as I understand it:

In normal operating mode, the charge controllers are attempting to first bulk, absorb and then float the batteries.  Once they are fully charged, or whenever we bump against the the upper charge limits set, the voltage starts to climb if there is no place else for power to go.  Initially the load diversion comes into play.  Through the Aux 2 (PWM relay signal) the Classic diverts, or burns off, excess available power into a water (pre) heater.  I'm planning to increase the capacity of this, but otherwise as it currently as it is working off our mx-60.  I've been reading Chris' post(s) regarding the order of these - and with a more wind capacity that could change.

When the batteries are full and the water heater is satisfied, the Aux 1 (non-PWM relay signal) starts to engage our homemade 'clipper' via the 'dump relay'.  This one, unlike the diversion load, is on the 3-phase side of the rectifier.  It's mission is just to keep the voltage input into the CC's below safe limits (250VDC, 180VAC).

The Omron looking to limit voltage independent of the CC's via our 'hi-limit relay'.  The resistors/clipper are on the line side of the hi-limit.  If the Omron actuates it should both disconnect the turbine from the rectifier(s) and close in the load bank.  Rob Becker has done this with a DP relay, but I believe the result is the same.

If the MS Clipper were available earlier, we might have chosen differently.  This is where we are.  Open to thoughts.

Reegard, ~ks