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Specs for the motors:

At 3VDC we measured 150mA @ 120 RPM no-load, and 1.1 Amps when stalled.

At 4.5VDC we measured 155mA @ 185 RPM no-load, and 1.2 Amps when stalled

At 6VDC we measured 160mA @ 250 RPM no-load, and 1.5 Amps when stalled.

I was looking around for some motor drivers to drive 4 of those motors. I'm planning to go with the L293D (which I already have 1 of, so I would only need 1 more) or DRV8833 (which I would need 2 of).

I'm sure that the DRV8833 is definitely capable of driving those motors, but I'm not sure about the L293D (which would be preferable considering its price and that I need only one more)

According to the specifications of the L293D motor driver on the website, these seem to be able to drive motors below 600mA, which I believe should be fine for the motors, however, it lists that it can handle a peak of only 1.2A, but the motors states that it can go up to 1.5A of current when stalled at 6VDC (not sure what stalled current means, exactly, but it's bugging me a bit).

Would the L293D be just fine for this or would, say, the DRV8833 be a bit more suitable for the motors? Would appreciate any help, thanks!

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  • \$\begingroup\$ Check the voltage drop across the L293, you will lose about 1.5 volts to your motor. I would suggest using a driver with a MOSFET output you will like the performance increase. \$\endgroup\$ – Gil Jun 13 at 3:38
  • \$\begingroup\$ @Gil Got it. Just curious, do you have any recommendations for motor drivers with a MOSFET output? \$\endgroup\$ – Hao C. Jun 13 at 4:02
  • \$\begingroup\$ I would rather not recommend a part as there are many available from several manufacturers available. Check with your favorite supplier. I typically use BTS7960 which is way overkill for your application. \$\endgroup\$ – Gil Jun 13 at 4:19
  • \$\begingroup\$ L293, L298 and SN754410 H-bridge drivers on low voltage power supply. \$\endgroup\$ – Andy aka Jun 13 at 8:30
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Stall current is what the motors pull when they're not spinning. Unless you plan on starting them spinning by some external method, you'll be exceeding the L293D's maximum output current every time you start the motors--or if there's ever a load that they can't provide enough torque to overcome.

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  • \$\begingroup\$ Ah, thanks for the explanation! In that case would the DRV8833 just be the best choice, or are the other motor drivers that would be a better choice? \$\endgroup\$ – Hao C. Jun 12 at 23:56
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Specs for motor

120/3 = 40 RPM/V
185/4.5=41.1
250/6 = 41.66

But you notice the difference on starting torque.
3V/1.1A = 2.73 ohms effectively.
4.5/1.2 = 3.75.
6.0/1.6 = 3.75

Your results will be equivalent to the voltage that is 1.5 V less than your battery because this is the nominal drop on the L293D’s. So you would need at least 4.5 but then you could use a supply that is 1.5V higher than 6V for battery power but then the gears might not like the higher RPM if there is no load, so 7V if possible is safer if not overloaded.

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  • \$\begingroup\$ Got it, will use 7V for the L293D in that case, thanks! So, just to confirm, is L293D would be fine to use with this motor? Or is the stall current too high for the L293D? \$\endgroup\$ – Hao C. Jun 13 at 0:37
  • \$\begingroup\$ Stall power dissipation needs a 5W heatsink so not a great idea if it is overloaded, but you could add a 1A PTC or less but then your motor needs to have much more torque capability than load \$\endgroup\$ – Tony Stewart EE75 Jun 13 at 0:57
  • \$\begingroup\$ Ah I see, thanks! \$\endgroup\$ – Hao C. Jun 13 at 1:19
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not sure what stalled current means, exactly, but it's bugging me a bit

Stall current is what the motor draws when you power it and 'lock' the shaft so it can't spin. Without spinning the motor can't generate a voltage to oppose the input voltage, so it will draw current according to its DC resistance. Most motors are not designed to do this for more than a few milliseconds when starting up, and will rapidly overheat and burn out if they stall.

Your motors have thin metal brushes and a plastic end-bell which will melt if it gets hot. Do not try to stall them or allow them to stall. If a motor burns out it may become a short circuit and destroy the H bridge controller too.

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  • \$\begingroup\$ Thank you so much for the explanation, will definitely keep that in mind! \$\endgroup\$ – Hao C. Jun 13 at 6:36

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