Hi Jim
On (31 May 96) Jim Mcandrew wrote to All...
 JM> Follow up on Risky Hydro thread...
 JM> Generator:  20hp, 1750rpm, 3ph, 575V, TEFC Toshiba Premium
 JM> efficiency motor used as an induction generator at 480V system
 JM> voltage 
 JM>  
 JM> Wire run:  about 2000' of #8AWG Tray Cable strung on insulators
 JM> attached to trees.  (Up to 60V drop in transmission = 1.5 kw loss
 JM> at max. power)
 JM>  
 JM> Capacitors:  7 Kvar at generator end of transmission line to
 JM> correct power factor and minimize amps and losses in the wire
 JM> run.
 JM>  
 JM> Grid Intertie:  Power Co. required  Over & Under Voltage, and
 JM> Over & Under Frequency relays.  We used inexpensive devices from
 JM> TimeMark Corp. and got off cheep at about $350 total for the two.
Good one! Seems you knew what you were doing and had some good theoretical
advice.
Do those Relays prescribed by your Power Co, operate with the contacts in a
battery supply? Control and protection relays don't always function 
orrectly,
if the control circuits are AC.
I am remembering the technical reports, after the [in]famous NE USA blackouts
15? 20? years ago? Control room operators at some sites were examining their
switch console settings by flashlight, and airliners were circling blacked 
ut
airports whose radio comms [failed] were driven from 60Hz supply. We had 
uite
a few giggles here, because AUS utilities followed the UK practice of battery
dependence for secure circuits.
 JM> We have a manual reset arrangement to turn off the water in the
 JM> event of an electrical fault or grid outage.  This is advisable
 JM> so as not to waste water or overspeed the motor and bearings. 
 JM> This shutdown arrangement is a real Rube Goldburg.  A solenoid
 JM> keeps a latch closed until a fault condition.  On a fault , a
 JM> cable is released allowing a weight to drop which pulls on
 JM> another line closing the ball valves feeding the turbine.  To
 JM> prevent rapid closing of the valves and possible water-hammer
 JM> trouble, the weight is restrained by another cable connected to a
 JM> hydraulic door closer used as a dashpot.
Hope you have an independent speed governor or overspeed device. An
overfrequency relay is *NOT* an adequate detector for overspeed. If you add a
governor [eg flyballs] suggest you *DON'T* use a belt drive for it unless you
figure carefully, the results of belt failure. Which is often to open wide 
he
water gate [sorry! Politics again....]
 JM> We spent about $7,000 on pipe, wire, motor and other items, but
 JM> much of the electrical stuff, starters and meters, was scrounged
 JM> or salvaged from storage.
Cheap! More fun than buying a cute old auto.
>> CONTINUED IN NEXT MESSAGE <<
NO, I've said enuff.  Cheers.....ALEC
... ......Many people die of thirst but the Irish are born with one 
illigan]
--- PPoint 1.92
---------------