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Planetary Gearbox draw too mutch current.


I have two of these Tamiya 72001 Planetary Gearbox Kit, I am using them with my picaxe 28x1 starter kit.

The manual says "Do not use power source higher than 4.5V". However, the motor doesn't work with a power source lower than 6v, and even with 6V the motor barely moves and the motor drive (L293d) become extremely hot and after a few second of use it seems to shut down and the motor stops moving.

Will using 3C batteries instead of 4AA slove the problem?


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Thanks a lot for the info guys, I will try the L298.


I'm sorry, I thought we were talking about one of the "regular" gearbox. I checked out the unit, and the website was a bit vague about exact current draw. It said up to a "few" amps during stall and one should "keep an eye on your robot" or use stall sensors. At any rate, I think you simply have a big motor here.,

Take the advice of any of the guys above as to a recomendation for a bigger driver.

I don't think you simply need a bigger motor driver... This tamiya gearbox has been used in thousands of robots and many many robots here at LMR. Not a single person has had a problem running this unit off of a L293. Instead of looking for a bigger motor driver, I would start with why your gearbox is drawing so much juice. Have you run the motor directly off a battery and checked it's draw with a measure thingie? If it's current draw is withing acceptable limits, it would show that there is a problem with the L293 or with your wiring. If it is drawing a lot, you gotta start looking at how you stacked up the gears and if there is any dog-hair giving you problems.

I have used the normal tamiya motors (Twin gearbox and Double gearbox) and they work fine. However, the motor on the Planetary Gearbox is different, its mutch larger and the gearbox ratio is also different (ratio 400:1).

Motor draw 1A in freewheeling or stalling? L293 as I remember handles only 600mA continiously and 1.2A is spike current it can handle.

Is there is a motor drive that can handle more current?

Definitely :) For example L298 will give you 2A continious per channel. Just go ahead and google it! Or search through some online shops and you will find plenty of options :) Good luck!

Sounds like your gearbox might not be assembled properly and jamming.

At first I thought that is the cause of the problem, but the motor works fine, it only stops when the motor drive get too hot.

I think your motors are probably drawing more current that the motor driver chip can handle. Check both the motors running and stall current and also the L293D max current.