1. ## l297&l298 questions

I have normal design with l297 & l298 connected to bipolar stepper moter
I have 24V 14.6A power supply to control 4 moter
I use stepper motor type AWG22 UL 1007 2.12A /phase 2 Ohm /phase 7.2 mH/phase 200 N.cm Min 1.8 step
I have interface control 4 Axes ,it has a USB to delever 5V to the interface
and a parallel port to computer.
my questions are:
1- is it ok for using 24V power supply 14.6A for 4 stepper motor from l298 (out1 and out2 for one coil and out3&out4 ), there is no volt rate in the specification
of the motor.
2- I bought a board with l298 only then i add l297 to it, i found that he put in4007 ( I know that it is 1A) is it ok for protection the motor 2.12A.
3-can I use 5V from USB to delver to l297&l298 ( from interface card)
or from computer power supply.
4-how can we calculate the current flow from l298 , I have 2 phase motor , are two phases energized in the same time .
5- Vref for 2A /phase is 1.36V Imax=Vref/.68 is it ok
and this will limit the current flow from l298 to motor without what is the power supply is , when we use Ohm'low it must be 4V 2*2=4V
why we use 24v for the motor and how i can know that volt maybe burnt the motor .

2. Yes to most of your questions. 24v is good. The circuit will limit the motor current to Vref/Rsense.

The 4007 diodes won't work. They will get hot and burn out. Use 2 amp or higher diodes with a reverse recovery rating (Trr) of less than 200 nS.

3. Thanks for replay H500

4. 5) Stepper motors are current devices, not voltage. It takes a minimum voltage to cause the motor current to flow. The reason why higher voltages are used is because of the time it takes the current to reach its rated current value. The motor's inductance determines the time constant. The higher the voltage the sooner the current will reach its designed value. The driver circuitry will limit the current to the motor's maximum allowed value regardless of the power supply voltage. Therefore the rule is not to exceed the motor's designed current rating. Also current times voltage equals power. Each motor also has a power limit one should not exceed. A good designer keeps these parameters within their respective limits.

5. Thanks Koc62 for your replay , I have 8 wires in this motor , as the diagram I connect two wires together , so I have only 4 wires from the motor I will connect it to driver , the motor connect as bipolar serial , in that way his current is 2.12A , is ok to reach this current or I must limit it to 2A to prevent the l298 , can any one tell me the best way to understand the program EMC2 , from the web, also any one have a designee for l298 & l297 one layer in Eagle and all the file to do the board.

6. If the I298/97 is limited to 2A maximum then yes, you must limit it to 2A.
2.12A is close enough.
I used Gecko drivers so I don't have any diy info for your driver.
Not sure what you want to know about EMC2. There is the installation part and the configuration part. You can also look for videos for either part.

7. Bipolar parallel will almost certainly give you better performance. Serial has 4x the inductance.

8. Thanks my friends , I use now RL207 diodes 2A , is it OK.
The main question is I have 4 motors with 2 phase ,every phase work with 2A max current , my power supply 24V 14.5A is it enough to feed all motors with it 2 phases in same time? . if all motors work with 2 phases in the same time we must have big current .or they don't work in the same time .

9. No, you need fast recovery diodes. I think at least less than 300ns recovery time. You are dealing with fast pulses in that cicuitry area. This also means you need to have a proper circuit board layout. This is not something you can learn in this thread. You also need an oscilloscope to check for oscillations of your circuit, when you are designing your own. Thus your 'scope will need enough bandwidth to view nanosecond pulses.

Have a look at existing circuits. Try this one L297/298 Stepper Driver

10. Power supplies needs to be able to supply all the current demands and not drop the output voltage significantly. In your given case of 2A per phase and you have 2 phases per motor then 4 motors could draw 16A, under static conditions. If you stay in this state then yes you need a 16A power supply. In the real world when will this take place? For short periods of time the power supply capacitance may provide 18A - that depends on the storage capacitance of your power supply. Under live running conditions you may not reach that scenario. But I don't know that.

11. Thank for replay Koc62 , I ask if you have Skype , my code name fadimore , I want to chat with you if you don't mind and thanks for your information

12. No, I don't have skype, nor use chat lines.

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