Small DC Geared Motors                                                

CHARACTERISTICS AND RATED PERFORMANCE OF A GEARED MOTOR

Speed reduction by means of a gearbox results in increased torque.
The reduction/increase is determined by the gear ratio and efficiency of the gearbox.

Over-all efficiency depends on the number of reduction stages : one average is 90% per stage. Therefore: a two-stage reduction gives 90 x 90=80%; 3 stages will be 72.9% and a 4-stage reduction 66%.
The above mechanical loss effects the stall torque as shown left.
Stall torque of a geared motor can be calculated using the following formula:
-Motor stall torque x gear ratio x efficiency.

The output loading on a gearbox must never exceed the manufactures "specified rated torque" as this will cause premature gear failure.

It is particularly important to observe this at slow output speeds when the calculated output torque exceeds the specified rated torque.

GEAR BOX CONSTRUCTION AND FEATURES

INTERMITTENT DUTY
(Suitable for less than 2sec on & long enough off time)
STANDARD TYPE
AG, SG, BG
VG, VM, LG

STANDARD GEAR MECHANISM

Other than the output gear, the gears rotate
around a shaft that is fixed to the plate.

HEAVY LOAD
-self lubricating metal type.
SM, AM, BE, BM
-ball bearing at all stages
AP

NON-LUBRICATED METAL BEARING
GEAR MECHANISM
All gears, including the output gear, are
attached to the shaft and supported by non-lubricated
metal bearings. This type of mechanism is suitable for
medium load applications and continuous duty cycle
operation.

LOW COST VERSION - Plastic or sintered metal. EU, RU, LG, VG COMPACT SIZE TYPE
-Planetary
GU, FU, EU, RU

PLANETARY GEAR MECHANISM
A heavy duty type gear mechanism using 3
mating gears to transmit torque to the output
shaft. This type of mechanism is suitable for
limited space applications.

GEARED MOTORS SELECTION GUIDE

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