Product Manual

-30-
Application Mounting
For direct-coupled applications, align shaft and coupling carefully, using
shims as required under motor base. Use a flexible coupling, if possible,
but not as a substitute for good alignment practices.
Pulleys, sheaves, sprockets and gears should be generally mounted as
close as possible to the bearing on the motor shaft, thereby lessening
the bearing load.
The center point of the belt, or system of V-belts, should not be beyond
the end of the motor shaft.
The inner edge of the sheave or pulley rim should not be closer to the
bearing than the shoulder on the shaft, but should be as close to this
point as possible.
The outer edge of a chain sprocket or gear should not extend beyond
the end of the motor shaft.
To obtain the minimum pitch diameters for the flat-belt, timing-belt,
chain and gear drives, the multiplier given in the following table should
be applied to the narrow V-belt sheave pitch diameters in NEMA MG
1-14.444 for alternating current, general-purpose motors, or to the
V-belt sheave pitch diameters as determined from NEMA MG 1-14.67
for industrial direct current motors.
Drive Multiplier
Flat belt* 1.33
Timing belt† 0.9
Chain sprocket 0.7
Spur Gear 0.75
Helical gear 0.85
* This multiplier is intended for use with conventional single-ply flat
belts. When other than single-ply belts are used, the use of a larger
multiplier is recommended.
† It is often necessary to install timing belts with a snug fit. However,
tension should be no more than what is necessary to avoid belt slap or
tooth jumping.