# 150:1 Metal Gearmotor 37Dx73L mm 24V with 64 CPR Encoder (Helical Pinion)

 Pololu item #: 4697 45 in stock Brand: Pololu Status: Active and Preferred Free shipping in USA

Price break Unit price (US\$)
1 39.95
10 35.96

 Quantity: backorders allowed

This gearmotor is a powerful 24V brushed DC motor with a 150:1 metal gearbox and an integrated quadrature encoder that provides a resolution of 64 counts per revolution of the motor shaft, which corresponds to 9600 counts per revolution of the gearbox’s output shaft. The gearbox is composed mainly of spur gears, but it features helical gears for the first stage for reduced noise and improved efficiency. These units have a 16 mm-long, 6 mm-diameter D-shaped output shaft. This gearmotor is also available without an encoder.

Key specifications:

24 V 68 RPM, 100 mA 56 kg⋅cm (780 oz⋅in), 3 A

Alternatives available with variations in these parameter(s): gear ratio motor type encoders? Select variant…

## Overview

Measuring 37 mm (1.46″) in diameter, these brushed DC gearmotors are the largest and most powerful we carry. They are available in a range of gear ratios from 6.3:1 to 150:1 and with 12 V or 24 V motors, and all versions are available with integrated 64 CPR quadrature encoders on the motor shafts. The 12 V and 24 V motors offer approximately the same performance at their respective nominal voltages, with the 24 V motor drawing half the current of the 12 V motor. See the 37D metal gearmotor datasheet (2MB pdf) for more information, including detailed performance graphs for each gearmotor version. You can also use our dynamically sortable 37D gearmotor comparison table to search for the version that offers the best combination of speed, torque, and current draw for your particular application. A more basic comparison table is available below.

Rated
Voltage
Stall
Current
Current
(RPM)
Extrapolated
Stall Torque
Max Power
(W)

Without Encoder

With Encoder
(kg ⋅ cm) (oz ⋅ in)
12 V 5.5 A 0.2 A 1:1 (no gearbox) 10,000 0.5 7 item #4750
6.3:1 1600 3.0 42 12 item #4747 item #4757
10:1 1000 4.9 68 12 item #4748 item #4758
19:1 530 8.5 120 12 item #4741 item #4751
30:1 330 14 190 12 item #4742 item #4752
50:1 200 21 290 10 item #4743 item #4753
70:1 150 27 380 10* item #4744 item #4754
100:1 100 34 470 8* item #4745 item #4755
131:1 76 45 630 6* item #4746 item #4756
150:1 67 49 680 6* item #2829 item #2828
24 V 3 A 0.1 A 1:1 (no gearbox) 10,000 0.55 8 item #4690
6.3:1 1600 3.5 49 14 item #4688 item #4698
10:1 1000 5.5 76 14 item #4689 item #4699
19:1 530 9.5 130 13 item #4681 item #4691
30:1 330 15 210 13 item #4682 item #4692
50:1 200 23 320 12 item #4683 item #4693
70:1 140 31 430 10* item #4684 item #4694
100:1 100 39 540 8* item #4685 item #4695
131:1 79 47 650 6* item #4686 item #4696
150:1 68 56 780 6* item #4687 item #4697
* Output power for these units is constrained by gearbox load limits; spec provided is output power at max recommended load of 10 kg⋅cm.

Note: The listed stall torques and currents are theoretical extrapolations; units will typically stall well before these points as the motors heat up. Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for continuously applied loads is 10 kg-cm (150 oz-in), and the recommended upper limit for instantaneous torque is 25 kg-cm (350 oz-in). 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.

In general, these kinds of motors can run at voltages above and below the nominal voltages; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

The gearboxes are composed mainly of spur gears, but they feature helical gears for the first stage for reduced noise and improved efficiency:

On units with encoders, the encoder portion is protected by a black plastic end cap:

The end cap is easily removable if you need to access the encoder or want to slightly reduce the overall gearmotor size, but there is a little bit of base plastic that will remain, as shown in the pictures below:

## Details for item #4697

This gearmotor is a powerful 24V brushed DC motor with a 150:1 metal gearbox and an integrated quadrature encoder that provides a resolution of 64 counts per revolution of the motor shaft, which corresponds to 9600 counts per revolution of the gearbox’s output shaft. The gearbox is composed mainly of spur gears, but it features helical gears for the first stage for reduced noise and improved efficiency. These units have a 16 mm-long, 6 mm-diameter D-shaped output shaft. This gearmotor is also available without an encoder.

Key specifications:

24 V 68 RPM, 100 mA 56 kg⋅cm (780 oz⋅in), 3 A

Exact gear ratio: (25×30×30×25×40) / (10×10×10×15×10) = bb(150:1)

## Dimensions

Warning: Do not screw too far into the mounting holes as the screws can hit the gears. We recommend screwing no more than 3mm (0.12″) into the screw hole.

## 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 – 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 12 V motor at 12 V and a Hall sensor Vcc of 5 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.

## Gearmotor accessories

The face plate has six mounting holes evenly spaced around the outer edge threaded for M3 screws. These mounting holes form a regular hexagon and the centers of neighboring holes are 15.5 mm apart. We carry two brackets for these gearmotors: a stamped aluminum L-bracket (sold in pairs) and a sturdier, tombstone-style machined aluminum bracket (sold individually):

The 6 mm diameter gearbox output shaft works with the Pololu universal aluminum mounting hub for 6mm shafts, which can be used to mount our larger Pololu wheels (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 our 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:

For a general-purpose hex adapter, consider our 12mm hex wheel adapter (also available in an extended version), which lets you use these motors with many common hobby RC wheels, including Dagu Wild Thumper Wheels:

We have a number of motor drivers and motor controllers that work with these 37D mm metal gearmotors. We generally recommend our High-Power Motor Drivers, which are available in various power levels and versions, including some dual-channel shields for Arduino and dual-channel expansion boards for Raspberry Pi. Additionally, our VNH5019-based motor drivers, which are also available as single and dual carriers, are a good match for these gearmotors.

If you are looking for higher-level control interfaces, such as USB, RC, analog voltages, I²C, or TTL serial, consider our Simple Motor Controllers, Jrk motor controllers, or RoboClaw motor controllers; these controllers are available in various power levels several of which can handle these 37D mm metal gearmotors (we generally recommend a motor controller that can handle continuous currents above the stall current of your motor).

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

## Selecting the Right Gearmotor

We offer a wide selection of metal gearmotors that offer different combinations of speed and torque. Our metal gearmotor comparison table can help you find the motor that best meets your project’s requirements.

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