I am currently trying to control a montor using my arduino and a h bridge. The problem I face is that the h bridge gets very hot and I think it is not safe to operate under such a condition. I am also pretty sure that I am doing some things wrong, but due to lack of experience, I would be very glad if someone could provide feedback/advice on my setup. To make things easier, I provide a sketch of my circuit and technical data of the components used.
I use an external power supply which delivers 12V DC 1.4A. The h bridge is a L293D from Texas Instruments . The motor I use is a RS360-SH 
Sketch of my setup:
The sketch attached to this post shows a motor M connected to the left part of the L293D. The power supply is used to power the L293D, the motor (via L293D) and the arduino. DP1 and DP2 are digital pins which I set to a fix value. This seems to work OK. the motor runs in one or the another direction.
- Is it possible that the heat comes from the voltage applied to pin 16 of the L293D (VCC_1). I have seen in the datasheet, that the recommended voltage for pin 16 should be within a range of 4.5 - 7 V. In my case, 12 V are applied. Do I need to use a voltage regulator in this case? Is it better to apply a voltage of 5V or 7V to the circuit? Applying a higher voltage also means more current, which also means more heat? Is that correct?
- I also think that the L293D is somewhat underdimensioned for my motor. The data sheet mentions a max. current of 600mA per channel, but my motor draws 2.2 - 4.7A. Is this another factor, which makes the L293 very hot? If yes, could you recommend a better h bridge for my motor? Actually I would like to avoid buying a full motor shield, because of costs. If possible I would like to simply use a h bridge.
As a side note: the motor will be not be running constantly. I will only use it to pump some water. This takes perhaps 5-10 seconds, once a day.
Thank you very much for your help. I really appreciate your help. If you need more information, please let me know.
circuit.pdf (726 KB)