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For driving a linear motor, i wanted to use some motor driver IC among L293 or L293D or TB6612FNG. And motor which I am using, has a voltage rating of 12V and current rating is unknown. And according to datasheets, maximum current that can handle by each channel in driver IC seems to be 600mA/1A/1.2A. My query is, can I use these driver ICs for driving my linear motor and how I can determine the current consumed by the motor.?? Regards Akhil

akhil vijayakumar
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  • Measure the current consumption of the motor. – Bence Kaulics Oct 19 '16 at 13:10
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    Be aware of the significant limitations of the L293: http://electronics.stackexchange.com/questions/108686/what-h-bridge-drivers-are-preferred-for-applications-controlling-a-low-voltage-m – Andy aka Oct 19 '16 at 14:15

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Be careful of data-sheet bragging.
Am not suggesting that untruths are in the data sheets of L293 -it is very possible that one amp current can be accommodated. But perhaps not continuously, there is another limitation that should be considered - that of chip heat dissipation. My experience with L293 is that one amp will overheat the chip, if you use the epoxy dual-inline package. Since epoxy is a poor heat-conductor, heat-sinking it does little good. The four ground pins to which the silicon die is bonded does conduct a little heat through the leads, which can help a little.
This bipolar-transistor chip is not the best for efficiency. Many MOSfet H-bridge chips waste much less power, and therefore need no heat sink.

A conservative motor-driving design would be able to accommodate a stalled motor without overheating the H-bridge driver. Your motor spec should either state "static armature resistance" or "stall current". This would be the highest continuous current passed through the H-bridge - and can be used to select an appropriate H-bridge driver chip.

glen_geek
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Your first choice should be to read the motor data that you used to select the motor. If you were so foolish as to buy the motor without knowing anything about it or if someone gave it to you, try to find the data sheet online or contact the manufacturer or seller. If that doesn't work, try to find a motor online that is similar and use that data.

There are tests that are used to characterize a motor. You will need to determine what type of motor it is and study the theory of operation and equivalent circuit for that type of motor. Find the appropriate test procedure. In general, start with a careful resistance measurement using a bridge or other instrument designed for low resistance measurement. Then perform no-load and mechanically-stalled current and power measurements. The stall test needs to be performed very quickly at reduced voltage to avoid damaging the motor. The tests will allow you to determine the general characteristics, but not the maximum continuous operating current that the motor will tolerate. You will need to determine that by comparison with other motors and monitoring the temperature.