Berkeley S.A.E., Installation, Repair, And Operating Instructions, Page: 6 / 28

FLYWHEEL COUPLING
The flywheel coupling transmits power from the engine
flywheel to the pump shaft. The maximum power that a
coupling can safely handle is shown by a rating number,
“R” ,
which is listed in the coupling dimensions tables.
When selecting a flywheel coupling for a pump and engine,
first determine the power rating that the pump will demand.
On the pump performance curve, find the RPM and BHP
values required to produce the application head-capacity
point.
Divide the BHP by the RPM, then multiply the result times
100. The result will be the
demand number for the pump.
For example, a B6JQBM can deliver 1500 GPM
at 260 feet Total Head when running at 2200
RPM. The power required by the pump will be
120 BHP. The demand number will be:
(120/2200) x 100 = 5.45
Next, select a coupling that can safely transmit the power, and
which will fit the flywheel dimensions. For a coupling to be
suitable, it must have an
“R” rating number GREATER
THAN the pump demand number. In the above example, the
minimum coupling “R” number would be 6 .
NOTE: The isolator disc design of Berkeley flywheel
couplings provides smooth power flow from the engine to the
pump, and torsional vibration problems are rare. However,
with the broad range of engines available, a torsional
mismatch can occur, which can cause excessive stress in the
pump shaft and coupling.
Torsional compatibility of the engine, pump, and coupling is
the responsibility of the assembler. Berkeley Pumps will
supply data for the pump and coupling for use by the
assembler for a torsional analysis.
NOTE: If the flywheel is fitted with a pilot bearing pressed into
a bore at the center, remove it to avoid interference with the
pump shaft.
FLYWHEELS FOR INDUSTRIAL TYPE
OVERCENTER CLUTCHES
Figure 3 on the facing page, shows the hollowed-out
appearance of the flywheels made for use with overcenter
type Clutch Power Take-Off assemblies.
These flywheels will have a recessed bore machined into the
face, and a set of tapped holes, which will be used to attached
the coupling to the flywheel. Dimensions are governed by an
SAE standard and are listed in Tables IIA and IIB, Figure 3.
The “Clutch Size” shown in the table is the nominal clutch
facing diameter for Drive Ring Type Overcenter Clutches.
For a new engine, the engine supplier can furnish the dim-
ensions.
For an existing engine, measure the flywheel dimensions, “D”
through “H”, using a tape measure and a machinists com-
bination square. Measurements to the nearest 1/32” will
usually be adequate.
When dimensions match a standard flywheel coupling listed in
Tables IIA, IIB, and IIC, Figure 3, select the one that has an
“R” rating number greater than the pump demand number.
• Record measurements on the dimension form on Page
23 in the spaces provided under Flywheel Dimensions.
OTHER FLYWHEELS
Some engines are fitted with flywheels especially machined
for coupling to other kinds of machinery (electrical generators,
torque converters, etc.), and require nonstandard flywheel
couplings. If the measured flywheel dimensions do not
correspond to dimensions listed in Tables IIa or IIb, write the
measured dimensions into the Dimension Form provided on
page 23, and send it to Berkeley for quotation of special
flywheel coupling.
Page 6 F00636
Flywheel Couplings
Installation