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  1. duke37

    180vdc to 75 vdc

    To drop 4A at120V with resistors will waste 240W and will need a lot of cooling. The way to do this will be a buck convertor but whether you can find one with the required high voltages is doubtful. Some mains power supplies start with a rectifier to give DC and then chop this down to the...
  2. duke37

    Parallel and series generator and batteries

    I see no necessity for this, if the generators are simple DC machines, in parallel they will run at the same speed which will be as they would naturally run in similar wind conditions. If they are rectified alternators, they will have the diodes built in.
  3. duke37

    Parallel and series generator and batteries

    Look up wikipedia Power optimizer Maximum power point tracking MPPT I have not played with these. There are devices on ebay which will charge two 12V batteries.
  4. duke37

    Ac led dimmer

    If your lamp has a rectifier and capacitor, then the capacitor will charge up and hold the light on. Some lamps are designed to dim and some not.
  5. duke37

    Parallel and series generator and batteries

    If the generators are identical with identical input speed then they can be connected in parallel and you can add up the currents. If the speed is not enough to produce 12V then no charging will occur. You may not get 6A unless there is a gale. It is possible to use a device to optimise output...
  6. duke37

    Electric part of the hay baler "Deutz Fahr GP 2.30"

    It may be possible to work out the action of the box by tracing out the circuit. I doubt if any computer is involved but I am no good at doing this. Others on the forum seem to be much better. It is obviously much better if the action of the box is known. As said previously, a baler has been...
  7. duke37

    power supplies in parallel?

    You would be better to split the LEDs into three so there is no argument between supplies. You will need a very, very thick cable to pass 160A with low voltage drop and low heating, even 50 or 60A is a lot.
  8. duke37

    Parallel and series generator and batteries

    To run a 24V system the batteries and also the generators need to be connected in series. You need similar turbines with the same wind speed.
  9. duke37

    Old Grundig TV repair

    If the capacitor is across the mains then 500V AC or 1000V DC would be better. There are capacitors made for this purpose, X type if I remember. If the capacitor is across the mains, it is probably there to stop interference being fed out to the mains, it does not affect the operation of the TV...
  10. duke37

    Electric part of the hay baler "Deutz Fahr GP 2.30"

    My brother has a square Welger baler which had an electronic system to control bale density via a hydraulic system. This caused trouble so the electronics and hydraulics were removed and the pressure is now controlled from the tractor. This is apparently quite satisfactory and is more reliable...
  11. duke37

    Protective grounding

    Transformers can be isolating or not isolating. The latter are known as auto transformers and are more efficient since the transformer only deals with the difference in voltage which may be quite low. When repairing valve radios I always use an isolating transformer and a RCD. I still do not...
  12. duke37

    Old Grundig TV repair

    It might be a 220nF 250V AC capacitor. If this is connected across the mains, it can be taken out for a trial. 250V AC is too low for 240V AC supply. Where are you and what is your mains supply? Brown rust might be a surpus of flux and should not be a problem.
  13. duke37

    Electric part of the hay baler "Deutz Fahr GP 2.30"

    I think that you are on a loser here. If the thing has been modified, then you will need information on what has been done. Checking the operation of a working machine is very dangerous and can be unpleasant from the dust. The picture shows that the unit has suffered from corrosion.The chances...
  14. duke37

    Help wanted on EL34 and 12AX7 tubes

    Take out the EL34s and measure the grid voltage. If it is not around -40 or -50V, then look at the way it is produced as has been mentioned. The voltage will not differ greatly when the valves are replaced since the current drain is low. This is of course different for the screens and anodes...
  15. duke37

    How to remove solder from plated-through holes?

    The desoldering iron I have was obtained from CPC (Farnel). I have only used it once as I am bodging old valve equipment at the moment. I do not remember the price but it was a special offer so about £5.
  16. duke37

    Help wanted on EL34 and 12AX7 tubes

    Take out the EL34 valves and measure the voltages at the valve sockets. There needs to be significant negative voltage, look up what is required from valve data. There are capacitors from the 12AX7 which can give positive voltage if leaky. Mullard gives 800V anode 400V screen -39V grid Power...
  17. duke37

    How to remove solder from plated-through holes?

    You can get an iron with a hollow bit and a sucker action. This keeps the solder liquid during sucking.
  18. duke37

    Help wanted on EL34 and 12AX7 tubes

    I do not know what an amp head is. Two countries separated by a common language? You need to put a load on the output for safety, a large resistor is best. If necessary use a short. (Do not do this with a transistor amplifier, they can be tested with an open circuit load) Short the input so...
  19. duke37

    Phase Shift Oscillator Op-Amp Neg Feedback

    I have seen simulations of oscillators which need to be started with a some sort of signal. Once started, the loop gain will keep it going. In a practical circuit, no noise is required because it is there with non ideal components. It is necessary that the amplifiers are biased into a...
  20. duke37

    Amps measurement of a battery

    Do you mean that you wish to measure the storage capacity which is quoted in Ah or mAh?
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