Pololu 4788 / 4789 Micro Metal Gearmotor HPCB 12V - 15:1 gear ratio

The Pololu 4788/4789 Micro Metal Gearmotor HPCB is a compact 12V DC motor with integrated 15:1 gear reduction, delivering high torque output in a miniaturized form factor ideal for robotics and embedded systems. Professional roboticists, automation engineers, and hobbyist developers rely on this motor for precision motion control in space-constrained applications requiring balanced speed and torque characteristics. This gearmotor solves the critical challenge of achieving sufficient holding torque while maintaining responsive acceleration in mobile robots, pan-tilt mechanisms, and automated positioning systems where standard DC motors lack adequate mechanical advantage.

Product Overview

The Pololu 4788/4789 Micro Metal Gearmotor combines a high-efficiency brushed DC motor with a precision-machined 15:1spur gear train, engineered to maximize power density while minimizing mechanical losses. The 15:1 gear ratio provides a 15-fold increase in output torque relative to the motor shaft, while reducing output speed proportionally, making it exceptionally suitable for applications requiring sustained holding force and controlled velocity. The HPCB variant features high-power ceramic ball bearings and hardened steel gears that withstand continuous operation at rated load, with minimal backlash for applications demanding positioning accuracy.

Operating at 12V nominal input, this motor delivers approximately 300 RPM output speed at no-load condition, translating to roughly 20 kg-cm of continuous torque output depending on load characteristics. The gearmotor architecture incorporates sealed bearing surfaces that protect against dust and moisture ingress, extending operational lifespan in field deployment scenarios. Pololu's precision manufacturing ensures consistent performance across production batches, with tight tolerances on gear tooth engagement and shaft alignment that reduce vibration and noise during operation.

Key Specifications

Specification	Details
Product Type	Micro Metal Gearmotor with Integrated Spur Gear Train
Brand	Pololu Robotics and Electronics
Origin	Original/Authentic
Warranty	7 days on manufacturing defects
Shipping	1-5 days from Bengaluru
Delivery	7-8 days across India
Support	24/7 via Email and WhatsApp
Nominal Voltage	12V DC
Gear Ratio	15:1
No-Load Speed	Approximately 300 RPM output
Continuous Output Torque	Approximately 20 kg-cm at rated load
Motor Shaft Diameter	3mm
Output Shaft Diameter	3mm with D-shaped profile
Bearing Type	High-Power Ceramic Ball Bearings
Gear Material	Hardened Steel with precision tooth engagement

Key Features

• 15:1 Gear Reduction: Provides 15-fold torque multiplication with proportional speed reduction, enabling sustained holding force in load-bearing applications without motor stalling
• High-Power Ceramic Ball Bearings: Sealed bearing design minimizes friction losses and extends operational lifespan under continuous duty cycles in robotics platforms
• Compact Micro Form Factor: Dimensions optimized for space-constrained mobile robots, quadcopter landing gears, and miniaturized automation systems where weight and volume are critical constraints
• Precision Hardened Steel Gears: Tight tolerances and hardened metallurgy reduce backlash to under 15 degrees, ensuring accurate positioning and smooth power transmission with minimal vibration
• Bidirectional Operation: Motor can be reversed for applications requiring forward and reverse motion control with identical torque characteristics in both directions
• Low Mechanical Losses: Optimized gear geometry and bearing preload minimize energy dissipation, delivering maximum usable torque output from 12V input power

Applications and Use Cases

• Mobile Robot Drive Systems: Powers differential drive platforms and tank-track robots where 15:1 reduction provides sufficient torque for climbing inclines while maintaining responsive acceleration on flat surfaces
• Pan-Tilt Camera Mounts: Delivers controlled angular positioning in surveillance and aerial photography systems, with 20 kg-cm torque supporting camera payloads up to 500g with smooth speed control
• Automated Door Locks and Actuators: Provides sustained holding torque in access control systems and motorized valve actuators requiring fail-safe operation without continuous power draw
• Robotic Arm Joint Actuation: Enables precise joint positioning in collaborative robot arms and industrial automation grippers where backlash minimization is essential for repeatable accuracy
• Conveyor Belt Drive Systems: Powers small-scale material handling conveyors in laboratory automation and packaging equipment where compact motor integration is required
• Winch and Pulley Systems: Provides mechanical advantage in miniaturized lifting mechanisms and cable-driven robotic systems for load positioning and tension control

How to Use

To integrate the Pololu 4788/4789 Micro Metal Gearmotor into your system, first identify the motor and output shafts: the motor shaft is the smaller diameter input, while the D-shaped output shaft transmits power to your load mechanism. Connect the two motor leads to your 12V power supply through a PWM motor controller or H-bridge driver circuit for speed and direction control; ensure proper polarity for forward rotation, reversing leads for reverse direction. Mount the gearmotor using the integrated mounting bracket or custom mechanical fixtures, ensuring the output shaft is properly aligned with your driven component to prevent binding and premature bearing wear. Apply load gradually during initial operation to verify smooth rotation and confirm adequate torque delivery before full-power deployment.

For optimal performance, implement current limiting in your motor controller to prevent stall currents exceeding 5A, which can damage the motor windings during locked-rotor conditions. Use PWM frequencies between 5-20 kHz for smooth speed control while minimizing audible noise from gear mesh harmonics. Monitor motor temperature during continuous operation; if the motor housing exceeds 60 degrees Celsius, reduce duty cycle or increase cooling to prevent thermal degradation of internal windings. For applications requiring precise positioning, implement encoder feedback or limit switches to detect load conditions and prevent mechanical overload scenarios.

Frequently Asked Questions

What is the difference between the 4788 and 4789 variants?

The Pololu 4788 and 4789 are mechanically identical gearmotors with 15:1 reduction ratio and 12V nominal operation. The primary difference lies in motor winding specifications: the 4788 is optimized for standard robotics applications with balanced speed-torque characteristics, while the 4789 features alternative winding for specific load requirements. Both units are compatible with identical mechanical interfaces and control circuits. Verify your specific application requirements with our technical team to select the appropriate variant for your load profile.

Can I operate this motor at voltages other than 12V?

The Pololu 4788/4789 is rated for 12V nominal operation with acceptable range of 10-14V for standard duty cycles. Operating below 10V significantly reduces torque output and may prevent motor starting under load. Exceeding 14V increases motor current draw and accelerates winding insulation degradation, reducing operational lifespan. For applications requiring voltage flexibility, consider using a PWM-based DC-DC converter to maintain stable 12V input while accepting variable source voltages. Never apply voltages exceeding 18V to prevent catastrophic motor failure.

How much backlash does this gearmotor have?

The Pololu 4788/4789 HPCB variant exhibits approximately 10-15 degrees of backlash in the gear train due to precision manufacturing tolerances and bearing preload optimization. This backlash is typical for micro-scale spur gears and is acceptable for most robotics applications including mobile robots and pan-tilt systems. For applications requiring backlash below 5 degrees, consider implementing external anti-backlash mechanisms such as spring-loaded idler gears or dual-motor differential drives. Backlash can be partially compensated in software through encoder feedback and closed-loop control algorithms.

What is the stall torque and stall current at 12V?

At 12V input with locked output shaft, the Pololu 4788/4789 produces approximately 40-45 kg-cm stall torque while drawing 4-5A stall current. Stall conditions should be avoided in normal operation as sustained stall current causes rapid thermal rise in motor windings. Implement current limiting in your motor controller to prevent stall currents from exceeding 5A for more than 2-3 seconds. Use mechanical load sensors or current monitoring to detect stall conditions and reduce applied voltage immediately to prevent winding damage.

Is this motor suitable for continuous operation?

Yes, the Pololu 4788/4789 is designed for continuous duty operation at rated 12V and loads up to 20 kg-cm output torque. Continuous operation generates heat in motor windings and gear train friction; monitor motor housing temperature and maintain it below 60 degrees Celsius for extended lifespan. At room temperature ambient conditions, the motor can operate indefinitely at 50-75% of rated torque. For 100% rated load continuous operation, ensure adequate ventilation or active cooling to dissipate heat and prevent thermal shutdown.

When will I receive my order?

Orders are dispatched within 1-5 business days from our Bengaluru warehouse. Delivery takes 7-8 days to most locations across India.

What is your return and warranty policy?

We offer a 7-day return policy on manufacturing defects only. Contact support within 7 days of receipt for free replacement or full refund. Not applicable for user damage or misuse.

Are bulk discounts available?

Yes, wholesale pricing for orders of 10 or more units. Contact our sales team via WhatsApp or email for a customized bulk quote.

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Buy Pololu 4788 / 4789 Micro Metal Gearmotor HPCB 12V - 15:1 gear ratio Online in India

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