Tamiya 70189 Mini Motor Low-Speed Gearbox (4-Speed) Kit

Tamiya’s 4-speed low-speed mini motor gearbox features a more compact 030-form-factor brushed DC motor driving a single gear train that can be assembled to have one of four gear ratios: 71.4:1, 149.9:1, 314.9:1, or 661.2:1. The gear train includes a self-locking worm gear.

AUD$ 26.95

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Description

Overview

The mini-motor gearbox kit from Tamiya makes it easy to get a small robot or plastic model moving. The kit includes one brushed DC motor and all the gears and parts to build any of the four possible gear ratio configurations: 71.4:1, 149.9:1, 314.9:1, or 661.2:1. The four gear ratio options give you the flexibility to choose the best speed and torque for your project.

The gear train of the low-speed gearbox includes a self-locking worm gear, which means the gear train can not be back-driven (the motor can spin the output axle in both directions, but you cannot turn the output axle with your hand). Not being able to back-drive the gear train is useful when powering vehicles that stop on steep inclines, or when powering mechanisms that lift heavy objects off the ground (like gates or drawbridges).

Parts included with the Tamiya 70189 mini motor low-speed gearbox (4-speed) kit with quarter for size reference.

The kit includes step-by-step illustrated instructions in both Japanese and English. A scanned copy of the instructions is available on the Pictures tab. The kit can be built with just a screwdriver, but the instructions recommend having side cutters, tweezers, and a modelling knife on hand. The gearbox kit’s motor has a 030 form factor that is smaller than the Tamiya gearboxes that use the Mabuchi FA-130 motor.

Box front for Tamiya mini motor low-speed gearbox (4-speed) kit

Instructions for Tamiya mini motor low-speed gearbox (4-speed) kit page 3

Box back for Tamiya mini motor low-speed gearbox (4-speed) kit shows the possible gear ratios in orange

Features

030-form-factor motor
- Speed @ 3 V: 8400 RPM
- Free-run current @ 3 V: 60 mA
- Stall current @ 3 V: 600 mA
- Stall torque @ 3 V: see picture to the right for torque table
4 different gear ratios, which can be adjusted by changing the final gear position
- 71.4:1
- 149.9:1
- 314.9:1
- 661.2:1
Self-locking worm gear prevents gear-train from being back-driven
3 mm hexagonal output shaft compatible with our adaptor for LEGO wheels and many of Tamiya’s wheels.
Two mounting orientations
Mounting holes designed to work with the Tamiya 70098 universal plate set and other Tamiya construction series products.
Transparent gear housing shows the internal mechanisms
Compact size of approximately 20 x 24 x 30 mm (0.8" x 1" x 1.2")

Note: The Tamiya 70189 mini motor low-speed gearbox (4-speed) is a kit; assembly is required.

Specifications

General specifications

Typical operating voltage:	3 V
Gear ratio options:	71.4, 149.9, 314.9, 661.2 :1
Free-run motor shaft speed @ 3V:	8400 rpm¹
Free-run current @ 3V:	60 mA²
Stall current @ 3V:	600 mA
Colour:	clear

Notes:

1: A theoretical speed of the gearbox output shaft can be computed by dividing this speed by the gear ratio.
2: This is the no-load current of the motor when disconnected from the gears in the gearbox; the no-load current of the entire gearbox with the motor connected will be slightly higher and will vary depending on the gear ratio.

FAQs

Does this gearbox come with motors?: Yes, motors are included with the Tamiya gearbox kits.
How do I order the correct gear ratio for this gearbox?: The Tamiya gearbox kits come with all of the gears and parts necessary to build the gearbox in any of the possible gear ratio configurations.
Is this gearbox suitable for my robot or project?: This gearbox is an eduational kit that you have to put together yourself. It is designed for use in small, indoor projects. The gearbox comes with plastic gears and small, low-voltage motors; if you are looking to build anything meant to work outdoors or in a rugged setting, you should be ready to replace the gearbox often or consider using a more robust, pre-assembled gearbox.
What kind of speed and torque will I get from this gearbox?: You can extrapolate a theoretical torque and RPM of the gearbox based on the gear ratio you build, the motor voltage, and the motor speed and torque. In general, this gearbox is a toy, so if you need very precise specifications, you might consider a more industrial gearbox.
How will operating voltage affect motor lifetime? How bad is it to run these Tamiya motors at voltages exceeding the suggested 3 V maximum?: In general, the higher your voltage, the sooner your motors will die. Because these are toy motors, the manufacturer does not provide any official cycle-life specifications, but a customer of ours has conducted his own series of experiments that shed light on the relationship between operating voltage and motor lifetime. You can view Adam’s results here.