10 Advantages of Geared Motors stepper motor

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10 Advantages of Geared  Motors  stepper motor

 

Oriental Motor offers many pre-assembled geared motors for quality and consistency.   In addition, gearheads from our industry partners increase the torque range of our motors further to accomodate for more applications.

High Torque Output

When a geared motor is used, the motor's torque is multiplied by the gear ratio and gear efficiency.  A geared motor will output more running and holding torque than an ungeared, standard motor.  Along with higher torque output and strengthened rigidity, many related benefits can be realized as I will discuss below.  It all starts with torque.

Speed Reduction

Gearheads are also referred to as "speed reducers".  Gear ratios are sometimes referred to as "speed reduction ratios".   While speed controllers take care of speed reduction nowadays, gearheads were used to reduce the speed of a motor in the ancient past.  When a geared motor is used, the motor's speed is divided by the gear ratio.  For example, an 1800 RPM AC synchronous motor with a 5:1 gearhead will run at 360 RPM.

High Resolution

When I started supporting motion control applications a long time ago, some customers actually used gearing to increase their stepper motor resolution.  From what I remember, I believe they wanted to avoid purchasing a bipolar microstepping driver, which was more expensive at the time.

Drive Large Inertial Loads

When a geared stepper motor or servo motor is used, the inertial load that can be rotated increases by the square of the gear ratio in comparison with an ungeared motor of the same size.  Bascially, you can drive an exponentially bigger inertial load with geared motors. 

When using different types of motors, pay attention to how the inertial load is treated.  We show some examples below.

For AC motors, we follow this formula below.  When gear ratios are less than 3:1~50:1, we multiply the rotor inertia by the gear ratio squared.  For gear ratios of 60:1 or higher, we only multiply the rotor inertia by 2500 as there is a limit.

Shorter Positioning Time

For large inertial loads, the use of a geared motor will achieve a shorter positioning time than a standard type motor.  In the graphs below, we compare the fastest positioning time between an ungeared closed-loop stepper motor and a geared closed-loop stepper motorat 5:1 inertia ratio and 30:1 inertia ratio.  

As you can see, at 5:1 inertia ratio, the geared motor takes longer than the standard type.  However, at 30:1 inertia ratio, the geared motor can position faster until a certain point (540°).

Downsize

Since a gearhead can increase a motor's torque dramatically, a smaller geared motor can output equivalent torque as a bigger, ungeared motor.  In some cases, geared motors can offer downsizing benefits to machine design.  See an example below.

 

Improved Damping Characteristics

If the inertial load is large or acceleration/decleration rate is high, a geared motor can increase damping effects more effectively.  This ensures more stable operation compared to an ungeared motor; especially during starting and stopping.  Geared motors are ideal for applications where a large inertial load, such as an index table, must be driven.

 

Increased Axial and Radial Load

Both axial (thrust) and radial (overhung) loads are also increased due to the enhanced strength and rigidity of a geared motor.  For example, axial load and radial load for a 25W KII Series AC induction motor increase to 101 lbs and 22 lbs respectively.  

Increased Rigidity 

Geared motors have increased rigidity and are resistant to torsional forces.  Therefore, compared to standard motors, geared motors are less subject to issues caused by load torque fluctuations.  High stability and position accuracy can be expected even when there are fluctuations in load.  For example, the increased gear friction of a geared motor provides more holding torque for a security camera to stay in position even with strong winds.

Gears 'R Us

In recent years, Oriental Motor has expanded its own geared motor lineup as well as products from our industry partners such as Harmonic Drive, Brother, and Neugart.  Together we offer a massive gearhead selection for AC motors, brushless motors, and stepper motors.  A great advantage of working with a manufacturer that provides both the gearhead and the motor is that all torque values for each gear ratio is already calculated, and that products have already been tested together.

 

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