131:1 12V 37Dx73L - Metal Gearmotor with 64 CPR Encoder

Description

This gearmotor consists of a 12 V brushed DC motor combined with a 131,25:1 metal spur gearbox, and it has an integrated 64 CPR quadrature encoder on the motor shaft. The gearmotor is cylindrical, with a diameter just under 37 mm, and the D-shaped output shaft is 6 mm in diameter and 16 mm-long.

Features

• Supply voltage: 12 V
• Gear ratio: 131,25:1
• Speed: 76 RPM
• Maximum torque: 45 kg*cm
• Minimum current consumption: 0,2 A
• Maximum current consumption: 5,5 A
• Diameter: 51 mm
• Length: 73 mm
• Weight: 210 g

Supply voltage

Pololu 37D engines are available in two versions with the recommended voltage of 12 V and 24 V. These engines do not differ in power, but only with the current drawn, which for 24 V motors is half as low as for 12 V motors, which can be considerable easier when choosing drivers. It is possible to supply the motor with a lower or higher voltage, but this is associated with lower power or decrease their lifetimes, respectively.

Dimensions and weight

All motors have the same dimensions. Depending on the gear ratio, the gears differ in length, as shown in the technical drawing below. The metal gear housing has two tapped holes for M3 screws. The gearmotors weigh from 175 g to 210 g depending on the gear size.

Dimensions of 37D motors in version with encoders (units in mm).
Dimensions of 37D motors without encoders (units in mm).

Magnetic encoder

All Pololu 37D gearmotors are available in versions with a magnetic encoder and without an encoder. The encoder is mounted on an additional shaft on the opposite side of the main shaft. The shaft on which the encoder is mounted is led directly from the motor (without gear), which allows the installation of the encoder which works much more accurately than if it was mounted on the shaft behind the gear. The use of an encoder allows to determine the speed and position of the motor shaft and to apply these values in the PID controller feedback loop.

Single-sided shaft motor	Motor with double-sided shaft and mounted encoder	A motor with a double-sided shaft, an encoder and a removed plastic cover

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.

Color Function Red motor power (connects to one motor terminal) Black motor power (connects to the other motor terminal) Green encoder GND Blue encoder Vcc (3.5 V to 20 V) Yellow encoder A output White encoder B output
	Encoder A and B outputs for 37D mm 12V metal gearmotor with 64 CPR encoder (motor running at 12 V).

Wheels

The 6 mm diameter gearbox output shaft works with Pololu universal aluminum mounting hub for 6mm shafts, which can be used to mount larger Pololu wheels (60mm-, 70mm-, 80mm-, and 90mm-diameter) or custom wheels and mechanisms to the gearmotor’s output shaft as shown in the left picture below. Alternatively, you could use 6mm scooter wheel adapter to mount many common scooter, skateboard, and inline skate wheels to the gearmotor’s output shaft as shown in the right picture below.

Black Pololu 80x10mm wheels (adapter needed)	White Pololu 80x10mm wheels (adapter needed)	Black Pololu 80x10mm wheel with motor mounted
Wild Thumper wheels Chrome(adapter needed)	Wild Thumper wheels red matalic (adapter needed)	Wild Thumper wheel with engine mounted
Black scooter/skate wheels with 200 mm, 144 mm, 100 mm, 84 mm, and 70 mm diameters.		Aluminum Scooter Wheel Adapters

Brackets

The gearmotor face plate has two mounting holes threaded for M3 screws, and you can use our custom-designed 37D mm metal gearmotor bracket (shown in the left picture below) to mount the gearmotor to your project via these mounting holes and the screws that come with the bracket.

Brackets for 37D engines	Brackets for 37D engines	37D engine mounted on a platform with a Scooter wheel

Motor controllers

We have a number of motor controllers and motor drivers that work with these 37D mm metal gearmotors. In particular, we recommend VNH5019-based motor drivers, for which we have basic single and dual carriers and a dual-channel shield for Arduino.

RoboClaw 2x7A Motor Controller (V5B)	Pololu Dual VNH5019 Motor Driver Shield for Arduino	Jrk G2 24v13 - DC motor controller

Current sensors

We have an assortment of Hall effect-based current sensors to choose from for those who need to monitor motor current:

Current sensor module (0-20A) with ACS712-20	ACHS-7124 Current Sensor Carrier ±40A	Pololu 2452 - ACS711EX Current Sensor Carrier -15.5A to +15.5A

Types and parameters of 37D Pololu engines:

Our offer includes motors with gear ratios from 6.3: 1 to 150: 1, with a rated voltage of 12 V and 24 V. All variants of motors with gears are available with and without a magnetic encoder. In addition, gearedless encoder motors are available to fit gears from the rest of the 37D motors.