Windgenerator  Progress  Report :  7th  March  1995


With the next working bee rapidly approaching on  Sunday 19th March, I thought 
I had better let you know of recent developments. 

Mark has been very busy with his business, but hopes to have the brake power 
supply re-built by the weekend. (no rush in view of later developments...see 
below). Luckily the transformer, timer relay and solid-state relay seem to be 
OK, so we only had to spend a few dollars on bridge rectifiers & VDR's. We 
got a 2nd hand computer fan which will help keep the bits cool when its added 
to the box. I checked the brake solenoid today and it has a DC resistance of 
1.6 ohm - this seemed a bit low but we'll check with Westwind.

Having finally remembered to take a length of hardwood to Breamlea, I was in 
a position to disable the disk brake and test the rest of the machine: I 
turned on power, pressed the "reset" button and then removed the bolt from 
the disk brake. Things went normally for about 2 minutes, then the strange 
rough humming noises started again, gradually increasing in duration until 
virtually continuous. There was some associated increased vibration in the 
nacelle. At the base of the tower, the analogue kW meter was showing zero 
output, the trip LEDs were showing low volts, but the contactors DID NOT 
trip out to take the gen off-line!! Knowing that when it did trip, the blades 
would go into overspeed, I returned to the nacelle at top speed  and applied 
the wood to the disk brake: nothing happened- pushing as hard as I could 
didn't slow things down by even 1 r.p.m. However, after slewing it out of the 
wind, bringing it to a halt was relatively easy. Back to the microprocessor 
and the OVER VOLTS LED was the only trip indicated!!

This is not very good news, as we had been hoping that all the strange 
symptoms were due to the frying of the brake power supply. We now have a 
situation of multiple faults, occuring simultaneously. Comprehensive testing 
of all low voltage & mains voltage wiring, fuses, relays, contactors, 
transformers will now have to be carried out to determine the location of 
faulty components. If nothing turns-up then the microprocessor may have to go 
to Unidata in Perth for overhaul/calibration/replacement/burial!! Maybe, the 
W/G has been struck by lightning????

The other bit of recent news is that the data logger has been installed, and 
with Adrian's fancy software is recording hourly windspeeds, and times of any 
status (off-line/low speed/high speed) changes. There have been some problems 
interfacing the data logger to Justin's modem and the new phone line.

			     Michael Gunter