70:1 Metal Gearmotor 37Dx68L mm with 64 CPR Encoder
- 12V brushed DC motor with a 30:1 metal gearbox
- integrated quadrature encoder
- 64 counts per revolution
If you have any questions on this product please feel free to contact us.
*Disclaimer: The images are merely illustrative.
This gearmotor is a powerful 12V brushed DC motor with a 70:1 metal gearbox and an integrated quadrature encoder that provides a resolution of 64 counts per revolution of the motor shaft, which corresponds to 1920 counts per revolution of the gearbox’s output shaft. These units have a 16 mm-long, 6 mm-diameter D-shaped output shaft.
Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes; a general recommendation for brushed DC motor operation is 25% or less of the stall current.
Dimensions of the 37D mm metal gearmotor with 64 CPR encoder. Units are mm over [inches]
These motors are intended for use at 12 V, though in general, these kinds of motors can run at voltages above and below the nominal voltage (they can begin rotating at voltages as low as 1 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.
Using the Encoder
A two-channel Hall effect encoder is used to sense the rotation of a magnetic disk on a rear protrusion of the motor shaft. The quadrature encoder provides a resolution of 64 counts per revolution of the motor shaft when counting both edges of both channels. To compute the counts per revolution of the gearbox output, multiply the gear ratio by 64. The motor/encoder has six color-coded, 8″ (20 cm) leads terminated by a 1×6 female header with a 0.1″ pitch, as shown in the main product picture. This header works with standard 0.1″ male headers and our male jumper and precrimped wires. If this header is not convenient for your application, you can pull the crimped wires out of the header or cut the header off. The following table describes the wire functions:
|Red||motor power (connects to one motor terminal)|
|Black||motor power (connects to the other motor terminal)|
|Blue||encoder Vcc (3.5 – 20 V)|
|Yellow||encoder A output|
|White||encoder B output|
The Hall sensor requires an input voltage, Vcc, between 3.5 and 20 V and draws a maximum of 10 mA. The A and B outputs are square waves from 0 V to Vcc approximately 90° out of phase. The frequency of the transitions tells you the speed of the motor, and the order of the transitions tells you the direction. The following oscilloscope capture shows the A and B (yellow and white) encoder outputs using a motor voltage of 12 V and a Hall sensor Vcc of 5 V:
Encoder A and B outputs for 37D mm metal gearmotor with 64 CPR encoder (motor running at 12 V).
By counting both the rising and falling edges of both the A and B outputs, it is possible to get 64 counts per revolution of the motor shaft. Using just a single edge of one channel results in 16 counts per revolution of the motor shaft, so the frequency of the A output in the above oscilloscope capture is 16 times the motor rotation frequency.
- Working voltage: DC12V
- Gear Ratio: 70:1
- No-Load Speed 157rpm @ 12V
- No-load current 250mA@ 12V:
- Stall Current: 6.5A@ 12V
- Rated Torque 28Kg.cm @ 12V
- Motor Size: 37Dx52L mm
- Shaft Size: 6mm Diameter x 16mm Length
- Weight: 200g
- Lead length: 20cm
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