How Determine Sensing Resistor Value?

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How Determine Sensing Resistor Value?

Postby daren208 » Sat Nov 20, 2010 3:09 pm

Hi, I am planning to use stepper motor 42BYGHD-444 . And the current rating is 0.5 A. May I know 0.5A is maximum current rating ? I am wonder what suitable value of sensing resistor is require to make sure the motor work without over current .

Let say my Sensing reference voltage is 0.5 V. So can I put sensing resistor value with 1 ohm ? to limit current to 0.5 A ? or what suitable value can of sensing resistor can I use for this model of stepper motor with reference voltage 0.5 V?
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Re: How Determine Sensing Resistor Value?

Postby shiyan » Sat Nov 20, 2010 4:50 pm

daren208 WROTE:Hi, I am planning to use stepper motor 42BYGHD-444 . And the current rating is 0.5 A. May I know 0.5A is maximum current rating ? I am wonder what suitable value of sensing resistor is require to make sure the motor work without over current .

Let say my Sensing reference voltage is 0.5 V. So can I put sensing resistor value with 1 ohm ? to limit current to 0.5 A ? or what suitable value can of sensing resistor can I use for this model of stepper motor with reference voltage 0.5 V?


Actually you don need to have current sensing if you can control the voltage. V=IR. The R of stepper motor come from the coil itself and it's fix, so if you control your V, you control the I.

0.5A is really low. If you really want to sense the I, you need to get yourself a resistor with very low resistance as the key to sense current is not to affect the circuit loading. But you need to connect it in series in order to sense the current go through it. You will need to get higher power resistor, normal 1/4 watt resistor is not useful in this situation. 1W or higher. If your reference voltage is 0.5V mean you need to get 1 Ohm of resistor.
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Re: How Determine Sensing Resistor Value?

Postby daren208 » Mon Nov 22, 2010 4:43 pm

okay. Thanks. Then I just ignore the sensing feature by provide the constant power supply to motor . :D
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