MM-C1025-P02560-045B

Coreless brushed DC planetary gearmotor. 10 mm envelope, 256:1, 4.5 V.

Class: Coreless brushed DC
Lifecycle: active
Revision: A
Review: Verified record
Sample: Sample available from configured stock
Lead time: 8 to 12 weeks for a first configured release
Verified: 2026-08-18

Envelope and model

Side elevation of MM-C1025-P02560-045B, drawn to scale from the published envelope: gearhead ⌀10.0 mm by 18.7 mm, motor body ⌀10.0 mm by 24.6 mm, 43.3 mm overall. The interactive model on this page is the C1025 motor body alone; the gearhead is not in it. Shaft extension, mounting face and every tolerance are governed by the controlled drawing.

Model bounding box, X × Y × Z: 10.0 mm × 10.0 mm × 28.4 mm
Model revision: A, reviewed 2026-08-18
Mesh: 1,620 triangles

Reviewed specifications

Every value with its basis. A maximum is a limit, not an operating point.

MM-C1025-P02560-045B specifications
Specification	Value	Basis	Note
Motor class	Coreless brushed DC	Published
Gear type	Planetary, 4 stages	Published
Output rotation	Same as the motor	Published
Envelope diameter	10mm	Published	Largest envelope diameter in the assembled stack.
Total length	43.3mm	Calculated	Motor body plus gearhead length. Shaft extension and mounting features are shown on the controlled drawing.
Reduction ratio	256:1	Published
Rated voltage	4.5V	Published
No-load output speed	55.1rpm	Calculated	Motor no-load speed divided by the reduction ratio. Real no-load output speed is lower by the gearhead drag torque.
Rated output speed	47.3rpm	Calculated	Motor speed at its rated point divided by the reduction ratio.
Continuous output torque	57.2mN·m	Calculated	Motor rated torque multiplied by the ratio and the typical stage efficiency. Verify on the bench before release.
Gearhead rated output torque	147mN·m	Maximum	Gearhead rated output torque. Do not size a configuration above this limit.
Torque margin	2.57x	Calculated	Gearhead rated output torque divided by the calculated continuous output torque.
Rated current	184mA	Published
No-load current	15mA	Published
Stall current	1,190mA	Published
Typical gearhead efficiency	43%	Typical	Typical value for the stage count. Efficiency falls with temperature, speed and run-in state.
Motor mass	10.7g	Published	Motor body only. Gearhead mass is confirmed on the controlled drawing.

P = T × ω = 57.2 mN·m × 47.3 rpm = 0.28 W

P: mechanical output power at the rated point
T: calculated continuous output torque
ω: rated output speed, converted to radians per second

Mechanical output only. Input electrical power is the rated voltage times the rated current; the difference is copper, iron, brush and gear loss, and it becomes heat inside the envelope.

Torque and speed trade on a line.

At a fixed terminal voltage the two move against each other, and the relationship is close enough to linear to size against.

Linear torque-speed approximation for MM-C1025-P02560-045B, built from the published no-load output speed (55.1 rpm) and the stall point of the MM-C1025-045B winding carried through the 256:1 reduction at 43% typical efficiency (396.288 mN·m). The dashed portion is past the gearhead's rated output torque: the motor can reach it, the gearhead is not rated for it. This is a construction, not a measured curve.

The same line as numbers
Output torque mN·m	Output speed rpm	Point
0.0	55.10	No load
57.20	47.30	Rated continuous point
99.1	41.33	Linear interpolation
198.1	27.55	Linear interpolation
297.2	13.78	Linear interpolation
396.3	0.00	Stall of the winding
147.0	34.66	Gearhead rated output torque, a limit

Assumption

What the line assumes

A brushed DC motor's torque falls linearly with speed at a fixed terminal voltage, so the motor line is a straight line between no-load speed and stall. Carrying it through the gearhead multiplies torque by the ratio and the efficiency and divides speed by the ratio. The construction ignores gearhead drag torque, which lowers the real no-load output speed, and it ignores the fall in efficiency and in magnet strength as the unit heats. Treat it as the shape of the relationship and confirm the operating point on the bench.

Compatible parts

Configurations in the same output band

Alternatives at a comparable speed and torque
Configuration	Diameter mm	Ratio :1	No-load output speed rpm	Continuous output torque mN·m	Rated voltage V
MM-C0817-P02560-030A	8	256	62.5	22.3	3.0
MM-C1726-P01575-120A	17	157.46	45.3	150.2	12.0
MM-B2419-S00325-240A	37	32.5	267.7	58.1	24.0
MM-C1024-P00640-030A	10	64	197.7	40.3	3.0

Application fit and cautions

Read out of this record's own numbers.

At the rated point this configuration delivers 57.2mN·m at 47.3rpm. That is 0.28 W of mechanical output inside an envelope 10 mm across and 43.3 mm long, and it suits slow positioning and holding duty, where the reduction does the work and the motor runs near its efficient speed.

Caution

Cautions for this configuration

The reduction is 256:1. Backlash and drag accumulate through every stage, so the real no-load output speed is below the calculated 55.1 rpm and positioning error at the output is dominated by the gearhead, not the motor.
4 stages. Each added stage costs efficiency and adds backlash, and the 43% figure used in the output torque is typical, not measured on your unit.
Brushed commutation. Brush life is set by current, speed and reversal rate at your operating point, and it is not a published value on this record. Ask for life data against your duty cycle before a production release.
Stall current is 1,190 mA at 4.5 V. Size the supply, the driver and any protection for that number, not for the 184 mA rated current.

Documents, models and next steps

Free and ungated

This specification record is free to read, index and quote, with no form in front of it. You should not have to trade personal data for enough information to reject a product.

A sanitized browser model (GLB, revision A, reviewed 2026-08-18) is published for this envelope: Download the GLB model

Not published yet

A 2D PDF drawing, a DXF and a neutral STEP file are not published for this record today, so there is no link here to a file that does not exist. A configured drawing carries tolerances and interface dimensions we will stand behind, which is why it comes out of a short qualified request rather than a download button.

Request a configured drawing

Record MM-C1025-P02560-045B, revision A, verified by Micro Motion application engineering on 2026-08-18. Catalog 2026-08-18.public.1.