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Everything posted by kumar_prashu

  1. Hello all, I am new to PCB designing. I want to get some PCB designing software for free. I had one ExpressPCB. But not sure about its versatility and use as a professional pcb maker. please tell me which software should i go for. Also, if i use ExpressPCB then, will I be able to design PCB card (physicallY) at my own or i have to order it to ExpressPCB office. thanks
  2. hello everybudy I have got a used motor with encoder , which it looks, have been drawn from CNC type machine. The rating plate (on the motor) only tells about rated voltage. and other things are missing.what soever it had mentioned, i m giving below On the motor: Canon precision japan FH-7-1756 CN-38-12301 Type- BB 2.6.N0.1 DC-12V, 3.3W On the Encoder: Shinko Electric Co. Ltd. customer No. FH7-5159 ------------ A similar other motor reads: FH-7-1758 pXN- 15EE23F 18893BC I am new to servo motors and dont know how to make sure about the rpm of the motor and other useful things rerquired to make it run. the encoder resembles like a disc with slits into it. so i assume that they are optical sensors. If someone can tell me about how to run these particular motor then thanks to him. Also if u could refer me datasheet or any other similar type of device, from which i can conclude. Thank you once again.
  3. Hello I need a sensor to locate the Exact position of the slot used in die casting machines. yes! for robotic application, Of Course.which type of sensor would be suitable for this type of operation, capacitive or any other. The same application requires to place the workpiece at a pre determined position in the slot. can anyone help! thanks in advance.
  4. Hello Can anyone giove me some good site for sensor applications, which shall provide me some free handbook on sensor. I need a sensor to locate the Exact position of the slot used in die casting machines. thanks in advance.
  5. Hello Sir once again! I am being told by the google groups that atx power supplies do not work well for the reactive load(motor) because of back emf. and that they are not designed for the continuous current since they operate on switching. I m in ambiguity. how can i make sure that none of my ckt element gets damaged. including controller (stepper motor -ucn 5804) and 89c52 mc.Please find the enclosed as such from the google page. One more thing, I want to use ICL7662, voltage doubler and my current req. is 2 amp max. can I use NPN transistors as darlington pair at the oupput of ICL7662, in this way getting voltage upto 38volt and the req. current to drtive the stepper motor. google page If I were you, I'd steer well clear of computer power supplies for anything except driving a computer. The big problem with them, other than the fact that they're not adjustable and lack the useful ammeters and voltmeters you find on a laboratory power supply, is that they are switch mode supplies. This means that, rather than using a bog standard isolating transformer, bridge rectifier and some other simple, rugged components, they use a complex mess of high frequency circuits and inductors to regulate the output. The principle is still a bit of a mystery to me, but it's something to do with applying raw mains (or whatever you're supplying it with) to the inductor and switching it on and off at the correct rate to produce the required output. Some models apparently don't even use an isolating transformer, which means that if they do fail, you might end up with mains voltage on all the output lines. Definitely not good. Of course, if they fail, they might also dump mains into all their internal components, and can sometimes explode quite violently if they go wrong (that's the cheap ones - better models have safety cut off devices) Another reason they're useless for robotics applications is that they must never be used to drive inductive loads, like any kind of motor, including steppers. This is because the added inductance buggers up the power supplies' internal inductor, and causes bad things to happen. Shorting them out has similarly catastrophic effects. They do have some advantages, though. The best (and one reason I do plan to use a similar device for some very specialised circuits in my own robot) is that, because of the charge-pump way the inductor works, they can easily produce output voltages greater than their input voltage, or with opposite polarity, and operate with almost any input, ac or dc. There isn't really any other practical way of doing this. Second, they are very small compared to conventional power supplies because they don't need a massive transformer (though, as mentioned above, this can lead to added mains hazards). The charge-pump effect also means that they could theoretically allow a battery to continue to supply it's specified potential when the emf of the cells themselves has dropped much lower than this value, so the system could run for longer without recharging (though certain types of battery might be permanently damaged by this). Finally, on PC switch-mode supplies, there is a signal sent back into the supply from the motherboard to shut the supply off immediately if it produces an incorrect output, to prevent damage to the motherboard. If you still plan to use the supply, you'll need to find a way to provide this signal.
  6. Hello Sir The IC for which you are talking about does not tell about the max. output current. Could you make it clear how should I design the subsequent stages ( O/P onwards) of the ATX power supply so that I can have voltages greater than 12 volts. and still satisfying my current requirement, which may vary from 1 amp. to 2amps.
  7. Thank You Sir In the last mail You had told about using ICL7660 to boost the voltage to 24 volts from the atx power supply.I have few questions: 1. Can I use the same type of IC to raise the voltage to 36 volts or more? 2. what are the restrictions imposed on this? Is the working principle of ATX power supply is the same as that of SMPS power supply? 3. what should be the power rating of the supply if my current requirement is up to 7 amps. using different voltage levels? 4. Do it support negative voltage levels too? Thanks in advance.
  8. Hello Everybudy can anyone tell me how to stop the stepper motor running at full steps/secs (full speed). I know that it operates on pulses but i have to put heavy load on the motor shaft so because of pulling action of load the motor may slip from the commanded position. My question is Can I apply the Pwm principle as applicable to the DC motors to completely stop the motor at its position. Also i want to know is that can motor be made to able holding more torque than the "Rated Holding Torque".
  9. Hello I m trying to make a variable voltage Rectified power supply using LM338. But i am facing an unusual problem of ripple at the output of LM338. when I set the Output at the particular voltage, the ripple current at the output just doubles the DC value. just as if DC o/p = 12 volts. AC o/p = 24 volts. The exact specs. of the components are as follows: Transformer- 220/15-0-15 volts, 5 Amps. (center tapped) Diodes- MIC 6A4 Cap.- 10,000 microfarad /25 volts.(at the o/p of rectifier) large value is just to keep the low ripple LM338: 0-5 Amps. input- output differential voltage = 3 volts Why do this happens. pls explain. I want to completely remove the ripple content.
  10. Hello can anyone help me in selecting an appropriate DC power supply for robot. I had heard it is advantageous if using ATX power supply for robots, but i dont know the basic difference between ATX power supply and simple rectified dc power supply. Is it suitable for continuous operation. The stepper motors I m using are of different ratings. as: 12volts/ 3.6volts/ 5 volts/ 24 volts. please suggest. The motors are likely to be operated simultaneously, but the overall current requirement will not exceed above 10 amps. Hw do I select the atx power supply? please advice.
  11. Hello Sir The motor i m using is 32volts/0.38amps. its 5 wire unipolar motor. i don`t know what type of heat sinks are employed for IC`s . could you pls tell me about that. also please tell me that is the IC capable of sustaining 32 volts at pin 2and pin no.7. thanks n regards
  12. Hello everbudy I am prashant. I am trying to make a stepper motor controller card using UCN5804B chip (allegro make). The problem is that i am not sure about the circuit shown in the datasheet of the Chip by the chip manufacturers. The circuit uses only diodes as an external elements. I want to know whether some other elementr such as current amp. are required or not, also is there need to put the chip on the HEAT SINK. The chip gets heated on application of power supply to the motor. is it damaged. also the pin no.-9 is showing CONTINUITY with earthed pins on the chip even when detached from the circuit board. please advice. thanks in advance. For yoy convenience i am attaching the datasheet of the chip. unipolar_driver.pdf
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