20
Maintenance and Field Adjustment
Impeller Rotational Speed Check
During clear skies and good sunlight weather
conditions, the drive system of the SolarBee
unit should operate:
1) At a rotational speed between 55 and 85
revolutions per minute (rpm).
2) In a clockwise direction when looking down
at the impeller.
Checking Rotational Speed
TOOLS RECOMMENDED:
Watch or Stopwatch
STEP 1: Locate the flag indicator on the
impeller shaft.
STEP 2: Start the stopwatch or mark a starting
point on the watch. Immediately begin counting
each full revolution of the flag indicator (starting
with "ZERO", "ONE", "TWO", etc) for a time of
less than or equal to 1 minute and at least 20
seconds. This step is easier with two people,
one counting revolutions and the other keeping
track of the time expired.
STEP 3: Quit counting revolutions and
immediately observe how much time has
expired in seconds.
STEP 4: Use the following equation to calculate
rotational speed in rpms:
(# Revolutions Counted X 60)
# Seconds Expired
DIVIDED BY
Revolutions Per
Minute (RPM)
=
Clockwise Rotation When Looking Down
Flag Indicator Section of Impeller Shaft
Flag Indicator
Example: 30 Revolutions were counted in a time
period of 30 seconds.
RPM = (30 revolutions X 60) / (30 seconds) = 60
Impeller Rotational Speed = 60 RPMs
