GM3 - Gear Motor 3 - 90 degree Shaft

SolarboticsSKU: RB-Sbo-02
Manufacturer #: GM3

Price  :
Sale price ¥988

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Stock  :
In stock, 5 units

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  • Voltage: 5vdc 
  • RPM: 38
  • Torque: (3.6 kg-cm)
  • Current: 52mA
  • Speed: 360 degrees/1.6 sec
  • Reduction: 224:1
  • Shaft length: 7mm double-flat (both sides)
  • Size: 70x22.5x37 mm
  • Weight: 37grams (1.31oz)

These GM3 - Gear Motor 3 - 90 degree Shaft are very comparable to a hobby servo for power, at a fraction of the cost! Fit perfectly with GMPW and GMW plastic wheels.

This gear motor rotate 360 degrees every 1.6 seconds (just a hair slower than a servo), at 5V, drawing 600mA at stall (free running at 52mA). With a 7mm double-flat output shaft (avoid using the "D" output - it's not meant to take rotational load), and a built-in clutch (limiting at 60 in.oz, but easily "locked"), and built-in mounting screw holes, you can see why we like these motors!

Based on the original design by Mark Tilden for use in the B.I.O.-Bugs (GM3 are now used for use in the Robosapien), these motors are the next generation with a variety of improvements such as dual output shafts and a lower current motor.

GM3 - Gear Motors are compatible with the Solarbotics Wheel Watcher Rotation Encoder. Use it if you need to control a robot for dead reckoning, tracking odometry (distance traveled), stalled motor, or closing the feedback loop for position/velocity/acceleration.

Customer Reviews

Based on 8 reviews
affordable nice motor/gear set

These are good motor/gear combo for small robots. There is surprising little slippage for a plastic gearbox. Would be nice if it had a hole for mounting an encoder closer to the shaft but I made it work.

Great little motor...

I am using this geared down motor for UGears Theater module, so as to animate it when the detector is actuated, using an Arduino Nano. The gearing ration is perfect for the use. Had a problem mounting the motor, but all came out well.

Good motor and gear, bad electrical connections

Motor, gears and shaft work well, recommend buying recommended wheel attachments together to ensure fit. Warning: Electrical leads are extremely delicate and will not survive more than one or two solder attempts. Ensure wires are secured after connections made, as this is how our electrical leads tore off due to wire movement.


This was my first puchase online from the RobotShop, but it will most certainly not be my last. The motor I purchased shipped the same day and arrived 2 days later! Plus, it was exactly as advertised and works like a charm. Thanks RobotShop --- keep up the great work!!

Robert J
Good Quality for the Price, but Difficult to Work With

Nice little motor. In fact all of the GM series motors are great - as long as you don't need to connect motor shaft to anything "off the shelf", i.e. gears, pulleys, couplings, shafts, wheels ... well pretty well anything for that matter. Problem is these guys have a 7mm dual flat shaft. Solarbotics has a GMW wheel that will connect, but unless you're willing to build something that connects to the GMW, you are pretty well euchred. You could make a shaft adapter on a 3D printer - if you have one - but this would be unsuitable for a commercial quality product. The only way I have been able to connect the shaft, is by turning a shaft coupling, drilling a 6mm axial hole, reaming it out to 7mm, and then using two set screws, 180 degrees apart to locate on the flats. But this is a lot of work - might as well pay a few $$$ extra and buy a motor with a round shaft. Otherwise excellent quality, but solder lugs break easily rendering motor as scrap.

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