Bill - you are doing great work in this pump testing (but what else would

 > I expect). Power measurements on a ac motor with current and voltage
 > is frequently very misleading because of "power factor" effects
 > ie phase shift due to the inductive nature of the motor. You will
 > almost always compute higher than actual. If you could get an
 > actual wattmeter it would be better, but they are not too common.
 > A DC motor would be a good option - actually many saw and most
 > router motors can be run on DC (just do not stall them or
 > they will quickly burn up) - Vance
 > >

 An old starter motor would be a good choice with up to 300 amps for
 short periods of time. 11 volts at 300 amps 3300 watts 4.4 HP.

 The problem is getting the power out. I'll machine a hub for
 a V belt pulley Bill if you come up with a starter motor.
 With all that torque available something like a two to one
 drive might be fine.

 Paul Lamar

Actually, I have obtained enough data for my purposes with the current setup.
 I would rather spend my time on building the rest of the plane and
installation rather than getting involved in setting up a DC motor, with a
controller to vary the RPM (DC motors run at whatever RPM they can, dependent
on the load) just to determine the power absorbed by the pump.

I was mainly interested in getting a handle on the flow rates and pressures
to be expected. This I have -- I will put the flow through the cores on the
previous chart in the next couple of days to see how it compares with the
curves already presented.

The actual power used is not as important to me, since I plan on using the
stock pump, driven from the belt. It is interesting how much the current rose
going between the 6" pulley and the 8" for the short duration that the
circuit breaker could take it. I believe that the power absorbed would go as
the square of the RPM.

Bill Schertz
KIS Cruiser #4045

Thanks again Bill. We should have some water temp drop data from Ed
any day now. With your data and Ed's temp data we could then get a 
feel for the BTU's rejected by the evap core cooling system.

BTW Our project to simultaneously record GPS data and rad air & water
temp data has been delayed a week or two. The GPS turned out to be
a Chatty Kathy hogging RS232 time so we need a way to disconnect it
and reconnect it once every couple of seconds. Turning the 
power off & on is not a good idea as it takes the GPS 
awhile to recover. 

Anybody know of a good quad CMOS analog gate that will work
with RS232 signal levels (+/- 12 Volts) ?
 
Paul Lamar
 
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