12V Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion)

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Pololu item #: 4750
Brand: Pololu
Status: Active and Preferred 
RoHS 3 compliant


This is the motor and encoder portion of our 12V 37D mm metal gearmotors with 64 CPR encoders. It does not include a gearbox, but the pinion gear on the output shaft works with all of our helical pinion 37D mm gearmotor gearboxes, so this can be used as a replacement motor or encoder for those gearboxes.

Key specifications:

voltage no-load performance stall extrapolation
12 V 10,000 RPM, 200 mA 0.5 kg⋅cm (7 oz⋅in), 5.5 A

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

Compare all products in 12V 37D Metal Gearmotors.

Pictures

12V Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion),

12V Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion).

37D mm metal gearmotor with 64 CPR encoder (no gearbox).

37D mm metal gearmotor with 64 CPR encoder (with end cap removed).

The 25D and 37D mm metal gearmotors with encoders have cables that are terminated with a 6-pin, 0.1″-pitch female connector.

Encoder A and B outputs for 37D mm metal gearmotor with 64 CPR encoder (12V motor running at 12 V).

Dimensions of the Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion). Units are mm over [inches].

37D Gearmotor (Helical Pinion) with the gearbox removed showing the helical pinion gear and first mating gear.




Overview

This 12 V motor with integrated 64 CPR (counts per revolution) quadrature encoder is intended as a replacement motor and encoder for our 12V 37D mm metal gearmotors with helical pinion gears.

The 2mm output shaft has a non-removable pinion gear that works with all of our “Helical Pinion” 37D mm gearmotor gearboxes. Note that we do not sell the 37D mm gearboxes separately, but if you have a gearmotor with a damaged motor or encoder (or if you want to effectively add an encoder to a version without an encoder), you can transfer the gearbox to this replacement motor.

37D Gearmotor (Helical Pinion) with the gearbox removed showing the helical pinion gear and first mating gear.

Dimensions

Dimensions of the Motor with 64 CPR Encoder for 37D mm Metal Gearmotors (No Gearbox, Helical Pinion). Units are mm over [inches].

This diagram is also available as a downloadable PDF (459k pdf).

Warning: Do not screw too far into the mounting holes as the screws damage the motor. We recommend screwing no more than 3.5mm (0.14″) into the screw hole.

Gearmotor Options

You will typically want to combine this motor with a gearbox to give it a more appropriate combination of torque and speed (without a gearbox, it offers very high speed with very low torque). Our 37D mm line of metal gearmotors consist of this motor combined with different gearboxes. We do not carry the gearboxes by themselves, so unless you are looking at this as a replacement motor for a compatible gearbox you already have, we strongly recommend you consider getting a preassembled gearmotor with the gear ratio that best suits your project requirements.

Rated
Voltage		 Stall
Current		 No-Load
Current		 Gear Ratio No-Load Speed
(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.

This motor is intended for use at 12 V, though in general, these kinds of motors can run at voltages above and below the nominal voltage; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

The black plastic end cap is easily removable if you need to access the encoder or want to slightly reduce the overall motor size, but there is a little bit of base plastic that will remain, as can be seen in the pictures below that show this motor combined with a gearbox:

37D mm metal gearmotor with 64 CPR encoder (with end cap removed).

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:

Encoder A and B outputs for 37D mm metal gearmotor with 64 CPR encoder (12V 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.

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.

Dimensions

Size: 34.5D × 46.5L mm1
Weight: 110 g

General specifications

Gear ratio: 1:12
No-load speed @ 12V: 10000 rpm
No-load current @ 12V: 0.2 A
Stall current @ 12V: 5.5 A3
Stall torque @ 12V: 0.5 kg·cm3
No-load speed @ 6V: 5000 rpm4
No-load current @ 6V: 0.15 A4
Stall current @ 6V: 3.0 A4
Stall torque @ 6V: 0.3 kg·cm4
Motor type: 12V
Lead length: 20 cm5
Encoders?: Y
Encoder resolution: 64 CPR

Notes:

1
Length measurement does not include motor shaft or pinion gear.
2
This motor does not have a gearbox.
3
Stalling can damage the motor. Stall parameters come from a theoretical extrapolation of performance at loads far from stall. As the motor heats up, as happens as it approaches an actual stall, the stall torque and current decrease.
4
This motor will run at 6 V but is intended for operation at 12 V.
5
May vary by a few centimeters.

File downloads

Recommended links

Frequently-asked questions

Is it okay to stall this motor at its operating voltage?

No! Stalls can 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, which means keeping continuously applied loads around 25% or less of the stall torque.

Additionally, for many of our gearmotors with high gear ratios, the extrapolated stall torque is beyond what the gearboxes are designed to handle, and a stall could instantly damage the gears. Make sure to keep applied loads within the published limits for your gearmotor.

What do the dotted lines mean in the motor performance curves from the datasheet?
In our motor performance curves, the solid lines show the regions where we actually took measurements while the dotted lines show extrapolations beyond that. For many motors, we took measurements out to about 50% of the stall torque, since continued operation at loads past this point increasingly risk thermal damage to the windings. However, for higher gear ratios, going to 50% of the stall torque exceeds what is safe for the gearbox, so the measurements are further limited to not much past our recommendation for continuously applied loads.

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