
Overview
CHIHAI CHF-GW12T-N20VA is a small DC motor driving a brass-framed worm gearbox, built for mechanisms that must hold their position when the power is cut: robot joints, powered furniture, focus and pan-tilt drives. The worm drive multiplies torque in a very short body and resists back-driving, resistance to back-driving depends on ratio and load; do not use it as a safety-rated brake.
Six ratios from 1:42 to 1:1030 are offered on three supply voltages, and the listing bundles the motor with brackets, a solder-free breakout board, a stepless speed controller or a DC power supply where you need them.
Features
- Worm gear reduction. A large reduction ratio in a short gearbox. Resistance to back-driving depends on the selected ratio and load.
- All-metal gear train. Wear-resistant and built for torque rather than speed, with good heat dissipation.
- Pure copper rotor winding. Low resistance and high conductivity, which is where the torque comes from.
- Ø3 mm D-cut shaft. 8 mm exposed with a flat, so pinions and couplings do not slip.
- Runs on PWM. Speed is adjustable and rotation reverses by swapping polarity.
- Brass gearbox frame. 8.50 mm wide, 18 mm tall, 33.5 mm overall, with two Ø1.4 mm mounting holes.
Configuration Guide
Motor winding: A35 against B45
Two motors are used. The A35 is the low-power winding: 0.2 W at 12 V and 0.1 W at 6 V, and it is the quiet, low-current choice. The B45 is the stronger winding: 0.6 W at 6 V and 0.15 W at 3 V, so it reaches higher speed and torque at the same ratio. Pick the winding that matches your supply first, then the ratio.
Gear ratio
1:42 is the fastest and 1:1030 the slowest. Select the required output speed and rated torque from the table for the exact motor and ratio; adjacent ratios do not follow a fixed doubling rule.
Steel-plate versions
The 1:236 and 1:302 ratios are also sold as a steel plate version. The steel-plate configurations use a different gearbox plate; select the exact listed configuration.
Package
Ten bundles run from the bare motor to a full kit with power supply, controller and breakout board. What each contains is listed under Package Contents, so check before ordering a bare motor if you also need a supply or a bracket.
Specifications
| Model | CHF-GW12T-N20VA |
|---|---|
| Brand | CHIHAI MOTOR |
| Motor type | Brushed DC with worm gear reduction, all-metal gear train |
| Output shaft | Ø3 mm D-cut (Ø3 -0.03 / -0.005), 8 mm exposed |
| Supply voltage | DC 3.0–12.0 V, fixed by the variant |
| Gear ratios | 1:42, 1:118, 1:236, 1:302, 1:603, 1:1030 — plus steel-plate 1:236 and 1:302 |
| Self-locking | Worm drive resists back-driving, with holding behavior dependent on ratio and load |
| Gearbox width | 8.50 mm |
| Gearbox height | 18 mm |
| Overall length | 33.5 mm max |
| Motor can | Ø12.1 mm max |
| Mounting holes | 2 × Ø1.4 mm, 4.0 mm apart |
| Mounting position | Horizontal or vertical |
| Weight | approx. 13 g (motor only) |
| Speed control | PWM, reversible |
Performance by Motor and Voltage
Four charts, one per motor and voltage combination. Torque is published in kgf·cm with the N·m equivalent. Slower ratios are longer and heavier in load terms, not in size.
DC 12V · A35 motor · 0.2 W
Rated and stall values describe different conditions. Stall-torque figures are shown as upper limits; do not use them as continuous load ratings. A continuous-duty cycle is not specified.
| Parameter | 1:42 | 1:118 | 1:236 | 1:302 | 1:603 | 1:1030 |
|---|---|---|---|---|---|---|
| No-load current (mA) | ≤65 | ≤65 | ≤65 | ≤65 | ≤65 | ≤65 |
| No-load speed | 550 rpm | 200 rpm | 100 rpm | 78 rpm | 39 rpm | 22 rpm |
| Rated torque | 0.05 kgf·cm | 0.15 kgf·cm | 0.3 kgf·cm | 0.4 kgf·cm | 0.8 kgf·cm | 1.2 kgf·cm |
| Rated torque | 0.005 N·m | 0.015 N·m | 0.03 N·m | 0.04 N·m | 0.08 N·m | 0.12 N·m |
| Rated speed | 390 rpm | 140 rpm | 70 rpm | 55 rpm | 27 rpm | 15 rpm |
| Rated current | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A |
| Stall current | ≤0.4 A | ≤0.4 A | ≤0.4 A | ≤0.4 A | ≤0.4 A | ≤0.4 A |
| Stall torque | ≤0.16 kgf·cm | ≤0.4 kgf·cm | ≤0.8 kgf·cm | ≤1.10 kgf·cm | ≤2.0 kgf·cm | ≤3.0 kgf·cm |
DC 6V · A35 motor · 0.1 W
Rated and stall values describe different conditions. Stall-torque figures are shown as upper limits; do not use them as continuous load ratings. A continuous-duty cycle is not specified.
| Parameter | 1:42 | 1:118 | 1:236 | 1:302 | 1:603 | 1:1030 |
|---|---|---|---|---|---|---|
| No-load current (mA) | ≤35 | ≤35 | ≤35 | ≤35 | ≤35 | ≤65 |
| No-load speed | 275 rpm | 98 rpm | 49 rpm | 37 rpm | 19 rpm | 11 rpm |
| Rated torque | 0.02 kgf·cm | 0.07 kgf·cm | 0.15 kgf·cm | 0.2 kgf·cm | 0.4 kgf·cm | 0.6 kgf·cm |
| Rated torque | 0.002 N·m | 0.007 N·m | 0.015 N·m | 0.02 N·m | 0.04 N·m | 0.06 N·m |
| Rated speed | 195 rpm | 70 rpm | 35 rpm | 27 rpm | 13 rpm | 7 rpm |
| Rated current | ≤0.08 A | ≤0.08 A | ≤0.08 A | ≤0.08 A | ≤0.08 A | ≤0.15 A |
| Stall current | ≤0.2 A | ≤0.2 A | ≤0.2 A | ≤0.2 A | ≤0.2 A | ≤0.4 A |
| Stall torque | ≤0.07 kgf·cm | ≤0.2 kgf·cm | ≤0.4 kgf·cm | ≤0.50 kgf·cm | ≤1.0 kgf·cm | ≤1.5 kgf·cm |
DC 6V · B45 motor · 0.6 W
Rated and stall values describe different conditions. Stall-torque figures are shown as upper limits; do not use them as continuous load ratings. A continuous-duty cycle is not specified.
| Parameter | 1:42 | 1:118 | 1:236 | 1:302 | 1:603 | 1:1030 |
|---|---|---|---|---|---|---|
| No-load current (mA) | ≤80 | ≤80 | ≤80 | ≤80 | ≤80 | ≤80 |
| No-load speed | 530 rpm | 190 rpm | 94 rpm | 74 rpm | 37 rpm | 22 rpm |
| Rated torque | 0.06 kgf·cm | 0.16 kgf·cm | 0.32 kgf·cm | 0.4 kgf·cm | 0.8 kgf·cm | 1.3 kgf·cm |
| Rated torque | 0.006 N·m | 0.016 N·m | 0.03 N·m | 0.04 N·m | 0.08 N·m | 0.13 N·m |
| Rated speed | 390 rpm | 140 rpm | 70 rpm | 55 rpm | 27 rpm | 15 rpm |
| Rated current | ≤0.20 A | ≤0.20 A | ≤0.20 A | ≤0.20 A | ≤0.20 A | ≤0.20 A |
| Stall current | ≤0.65 A | ≤0.65 A | ≤0.65 A | ≤0.65 A | ≤0.65 A | ≤0.65 A |
| Stall torque | ≤0.16 kgf·cm | ≤0.4 kgf·cm | ≤0.8 kgf·cm | ≤1.10 kgf·cm | ≤2.0 kgf·cm | ≤3.0 kgf·cm |
DC 3V · B45 motor · 0.15 W
Rated and stall values describe different conditions. Stall-torque figures are shown as upper limits; do not use them as continuous load ratings. A continuous-duty cycle is not specified.
| Parameter | 1:42 | 1:118 | 1:236 | 1:302 | 1:603 | 1:1030 |
|---|---|---|---|---|---|---|
| No-load current (mA) | ≤35 | ≤35 | ≤35 | ≤35 | ≤35 | ≤35 |
| No-load speed | 260 rpm | 90 rpm | 45 rpm | 35 rpm | 18 rpm | 11 rpm |
| Rated torque | 0.03 kgf·cm | 0.08 kgf·cm | 0.16 kgf·cm | 0.2 kgf·cm | 0.4 kgf·cm | 0.65 kgf·cm |
| Rated torque | 0.003 N·m | 0.008 N·m | 0.016 N·m | 0.02 N·m | 0.04 N·m | 0.065 N·m |
| Rated speed | 195 rpm | 65 rpm | 33 rpm | 26 rpm | 13 rpm | 7 rpm |
| Rated current | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A | ≤0.15 A |
| Stall current | ≤0.35 A | ≤0.35 A | ≤0.35 A | ≤0.35 A | ≤0.35 A | ≤0.35 A |
| Stall torque | ≤0.07 kgf·cm | ≤0.2 kgf·cm | ≤0.4 kgf·cm | ≤0.50 kgf·cm | ≤1.0 kgf·cm | ≤1.5 kgf·cm |
Mechanical Dimensions
The gearbox housing is 8.50 mm wide and 18 mm tall, with an overall body length of 33.5 mm max; the motor can is Ø12.1 mm max. The output shaft is Ø3 mm, 8 mm exposed, D-cut. Two Ø1.4 mm holes sit 4.0 mm apart for mounting, and the body can be fitted horizontally or vertically. The motor alone weighs about 13 g.
The outline drawing in Visual Details carries every dimension needed to design a bracket. Note that the D-flat is machined to Ø3 -0.03 / -0.005, so print the coupling bore to suit a 3 mm shaft rather than an interference fit.
Package Contents
| Package | What you receive |
|---|---|
| Motor Only | 1 × gear motor |
| Motor + Green Bracket | 1 × gear motor, 1 × green mounting bracket |
| Motor + Mini Speed Controller | 1 × gear motor, 1 × stepless speed controller |
| Motor + Solder-Free Board | 1 × gear motor, 1 × solder-free breakout board with lead |
| Motor + Solder-Free Board + Mini Controller | 1 × gear motor, 1 × breakout board with lead, 1 × stepless speed controller |
| Motor + Power Supply | 1 × gear motor, 1 × DC power supply |
| Motor + Power Supply + Mini Controller | 1 × gear motor, 1 × DC power supply, 1 × stepless speed controller |
| Motor + Power Supply + Controller + Solder-Free Board | 1 × gear motor, 1 × DC power supply, 1 × stepless speed controller, 1 × breakout board with lead |
| Motor + White Bracket | 1 × gear motor, 1 × white mounting bracket |
| Motor + Controller + Green Bracket | 1 × gear motor, 1 × stepless speed controller, 1 × green mounting bracket |
Applications
- Small robot joints and robotic arms
- Powered furniture and adjustable frames
- Focus, zoom and pan-tilt mechanisms
- Micro gimbals, locks and dispensing mechanisms
FAQ
Is it really self-locking?
The worm drive strongly resists back-driving, so a load stays put when power is removed. Treat that as a holding characteristic: it is not a certified brake, and a heavy or vibrating load can still creep.
What is the difference between A35 and B45?
They are different motors. A35 is the low-power winding (0.1–0.2 W), B45 the stronger one (0.15–0.6 W at its rated voltage). The B45 gives more speed and torque at the same ratio.
What does the steel-plate version change?
Only the gearbox plate for the 1:236 and 1:302 ratios. Ratio and winding stay the same; it costs one yuan more in the source listing.
Which way is the breakout board wired?
Two orientations are available, wired towards or away from the shaft. Orders without a note ship wired away from the shaft.
Do I need the power supply package?
Only if you do not already have a DC supply in the motor's voltage range. The bare motor comes with leads but no supply, bracket or controller.
Visual Details










