• 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 break horsepower (bhp) values
required to produce the supplication 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.
• 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.
• Torsional compatibility of the engine, pump, and
coupling is the responsibility of the assembler.
Franklin Electric will supply data for the pump
and coupling for use by the assembler for a
torsional analysis.
SAE Splined Shaft Applications
TABLES 1A & 1B
Engine Flywheel Dimensions
Clutch
E
BC
F
Size
8½"
6½"
7.88
3.94
OD
9½"
7½"
8.75
3.69
OD
103/8"
8"
9.62
4.81
OD
123/8"
10"
11.62
4.47
OD
137/8"
11½"
13.12
5.06
OD
183/8"
14
17.25
6.63
OD
To determine "R" Rating = Divide horsepower by rpm and multiply by 100
Example: (125/1800) x 100 = 6.94. A coupling with an "R" rating of 7 would be used.
D
G
H
Bolt Holes
Shaft Splint
Diameter
No.
Size
13/8" 10 T
1.19
1.69
6
5/16-18
1½" 10T
13/8" 10 T
1.19
1.69
8
5/16-18
1½" 10T
13/8" 10 T
2.44
2.94
6
3/8-16
1½" 10T
13/8" 10 T
13/8" 10 T
2.13
2.75
8
3/8-16
1½" 10T
1½" 10T
13/8" 10 T
13/8" 10 T
1.56
2.69
8
3/8-16
1½" 10T
1½" 10T
1.00
2.13
8
1/2-13
1½" 10T
Other Flywheels
• Some engines are fitted with flywheels specific to
other kinds of machinery (electrical generators, torque
converters, etc.) and require non-standard flywheel
couplings. These may be purchased from
third party vendors or suppliers.
Flywheel For Industrial Type Overcenter Clutches
• FIGURE 3 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 machine
into the face, and a set of tapped holes, which will
be used to attach the coupling to the flywheel.
Dimensions are governed by an SAE standard
and are listed in TABLES 1A and 1B, FIGURE 4.
The "clutch size" shown in the table is the nominal
clutch-facing diameter for drive ring type
overcenter clutches.
Flywheel Coupling
"S" Series
"R"
Part #
Rating
7
C-S-065138-1
7
C-S-065150-1
7
C-S-075138-1
7
C-S-075150-1
7
C-S-080138-1
7
C-S-080150-1
7
C-S-100138-1
9
C-S-100138-2
7
C-S-100150-1
9
C-S-100150-2
7
C-S-115138-1
9
C-S-115138-2
7
C-S-115150-1
9
C-S-115150-2
9
C-S-140150-2
FIGURE 4
7