25d-21-ENC Gearmotor (Gear Motor), With Encoder, Pololu gearmotor

Gearbox 21 mm long and 25 mm across, motor 30.8 mm: the 25d-21-ENC gearmotor (Pololu gearmotor, with encoder), with a 4 mm output shaft and two M3 holes. Its encoder adds 14.7 mm behind the motor. Download it as simplified STEP files.

How these parts are made, and what the levels mean: read the method

• Also searched as: 25d-21-ENC gearmotor
• Model id: gearmotors-pololu-25d-21-enc
• Standard: Pololu gearmotor · size 25d-21

Files

Part key	Simplified
gearmotors-pololu-25d-21-enc	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
D	Gearbox diameter		25		25	nominal	L2
Lg	Gearbox length		21		21	nominal	L2
Lm	Motor length		30.8		30.8	nominal	L2
Dm	Motor diameter		24.4		24.4	nominal	L2
E	Shaft length		12.5		12.5	nominal	L2
d	Shaft diameter		4		4	nominal	L2
f	Shaft across the flat		3.5		3.5	nominal	L2
B	Front boss diameter		7		7	nominal	L2
h	Front boss height		2.5		2.5	nominal	L2
dt	Mounting hole thread		3		3	nominal	L2
nh	Number of mounting holes		2		2	nominal	L2
th	Mounting hole depth		6		6	nominal	L2
e	Mounting hole offset		8.5		8.5	nominal	L2
Br	Rear boss diameter		6.4		6.4	nominal	L2
hr	Rear boss height		1.5		1.5	nominal	L2
lt	Terminal reach		4.2		4.2	nominal	L2
pt	Terminal spacing		18.1		18.1	nominal	L2
tw	Terminal width		2.1		2.1	nominal	L2
tt	Terminal thickness		0.3		0.3	nominal	L2
le	Encoder length		14.7		14.7	nominal	L2
De	Encoder diameter		25		25	nominal	L2

Drawing

As a PDF: CC-GM-POLOLU-SZ-25d-21.pdf.

The 25d-21-ENC gearmotor beside the 25d-19-ENC and the 25d-23-ENC

The 25d-21-ENC is number 3 of the 9 Pololu gearmotor gearmotors published here, listed from 25d-17-ENC to 37d-26.5-ENC.

• Gearbox diameter (D): 25 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Gearbox length (Lg): 21 mm on the 25d-21-ENC gearmotor, against 19 mm on the 25d-19-ENC and 23 mm on the 25d-23-ENC.
• Motor length (Lm): 30.8 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Motor diameter (Dm): 24.4 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Shaft length (E): 12.5 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Shaft diameter (d): 4 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Shaft across the flat (f): 3.5 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.
• Front boss diameter (B): 7 mm on the 25d-21-ENC gearmotor, the same on the 25d-19-ENC and the 25d-23-ENC.

The 25d-21-ENC gearmotor in its other versions

• 25d-21 Gearmotor (Gear Motor), Pololu gearmotor, with the same values.

Other sizes

• One size smaller: 25d-19-ENC Gearmotor (Gear Motor), With Encoder, Pololu gearmotor, 25 mm gearbox, 19 mm long, 4 mm D-shaft, Pololu and TT Motor data.
• One size larger: 25d-23-ENC Gearmotor (Gear Motor), With Encoder, Pololu gearmotor, 25 mm gearbox, 23 mm long, 4 mm D-shaft, Pololu and TT Motor data.

Documents

• CC-GM-POLOLU-DS-25d-21.pdf: 25d-21 datasheet: values with levels, sources
• CC-GM-POLOLU-SZ-25d-21.pdf: 25d-21 drawing: this size's values on the views
• parts.json: the part record of this size (the platform contract)

Sources

pololu-25d-gearmotors, ttmotor-gm25-370ca. Full citations: the method page and this size's datasheet.

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