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  1. Minder

    Whats the best schematics capture program?

    I really like Kicad, free open source and plenty of tutorials, both Kicad and others. No limit on size. Or are you looking for something that includes general CAD drawing such as Ladder and panel diagrams. I think you will have a job finding one for both. Probably better to get one of each that...
  2. Minder

    Calculating the value of the resistance for controlling the speed of AC fan

    If using a micro and wishing to use phase angle control with a Triac for a shaded pole motor. There is Fairchild AN-3006 and Picmicro AN958 for detecting the zero cross point for phase angle control. M.
  3. Minder

    Calculating the value of the resistance for controlling the speed of AC fan

    Most of these fan motors are shaded pole motors and if so can be controlled by a simple Triac dimmer circuit, just 1/2 doz components. Resistors are inefficient. M.
  4. Minder

    Microcontroller

    A start. http://www.angelfire.com/oh3/ebjoew/LCDDisplay.html Program towards the bottom of page. M.
  5. Minder

    What phase is this please

    Sorry my math was wrong, as you see by the plate it is 3HP. M.
  6. Minder

    What phase is this please

    RPM= 50hz X 60sec/pairs of poles - slip freq. 50x60/1 = 3000-140 cycles = 2860 rpm. M.
  7. Minder

    What phase is this please

    I see you are in UK so it would be easy to fit a 240v version. I see it is a 2 pole motor which is unusual for a compressor. This decides the RPM, the 4 pole version will be half the rpm. M.
  8. Minder

    What phase is this please

    Nice 3phase motor and 10HP! Not really a decent way to hook it up to 1phase. Compressors normally run under a fairly high load. You could try selling the motor and get a 1ph replacement. M. .
  9. Minder

    Anemometer switch

    If not familiar with micro's, another way would be a LM2907, freq to analogue IC and use a LM311 comparitor on the output to set what rpm value you want to trip. Then there is the issue of short momentary gusts, which probably should/would be ignored, This is where the micro has an edge, you can...
  10. Minder

    Getting 24V from a 5V sensor output

    Incidentally if the 5v sensor is open collector then you would need a ~10k pull up resistor to use with a FET. M.
  11. Minder

    Getting 24V from a 5V sensor output

    A logic level Mosfet, a small one is the 2n7000 up to 200ma. M.
  12. Minder

    How to control the field current of an alternator by using PWM?

    I think you will find the opposite is true, One reason why alternators replaced DC generators in auto's is the fact they have the ability to relatively high output at low rpm. M.
  13. Minder

    How to control the field current of an alternator by using PWM?

    It has already been answered, here and other forums, if you want to control the voltage via PWM with a fixed load on the output, then do you need more? M.
  14. Minder

    How to control the field current of an alternator by using PWM?

    I don't see a need to regulate the voltage if the alternator is feeding a fixed (e.g.resistive) load of some kind the load (effort) will increase with voltage for a given peddling rate. M.
  15. Minder

    How to control the field current of an alternator by using PWM?

    The alternator shown appears to not have an internal regulator so you should be OK feeding the field with a PWM signal, I assume you are increasing the voltage out into a fixed load in order to increase the effort needed to turn it. M.
  16. Minder

    How to control the field current of an alternator by using PWM?

    The modern regulator uses PWM now, the first style that replaced the old electro-magnetic type was an electronic version of it that produced radio interference, hence the transition to PWM. To control with your own PWM you have to remove the internal regulator if fitted and output the new PWM to...
  17. Minder

    Back diode

    Are you referring to BEMF diode application across a coil etc or zener diodes maybe? M.
  18. Minder

    Controlling a simple DC brushed motor by PWM

    If the 100Khz is the freq of the PWM that is fairly high, But I suspect you should be able to do it with a suitable Mosfet. If you Google PWM with Mosfet you should get many links to give you the general idea. M.
  19. Minder

    Controlling a simple DC brushed motor by PWM

    What is the nature of the PLC PWM output? Not sure what is available where you are in the way of selection but 60v 50a Mosfets are fairly plentiful...
  20. Minder

    Controlling a simple DC brushed motor by PWM

    One possible solution if reversal is needed, as you are using a PLC, total logic control can be achieved with a couple of spare outputs to control a common dual reversing contactor. M.
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