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  1. gurse

    Full Wave Bridge Rectifier Circuit

    https://res.cloudinary.com/engineering-com/image/upload/v1574757210/tips/ThyristorControlledRectifier_uxfgok.pdf Attached is the circuit diagram and It is a Fluke 77 series multimeter.
  2. gurse

    Full Wave Bridge Rectifier Circuit

    Although the question was put in that way, later in the discussion I pointed out that the main interest was the AC and DC voltages that I was measuring across the coil. But Waross pointed out that it could be due to metering errors.
  3. gurse

    Full Wave Bridge Rectifier Circuit

    Not yet, it is not speculation it is based on well established formulas.
  4. gurse

    Full Wave Bridge Rectifier Circuit

    The reason why I calculated the Vrms (Vp / √2) of the rectifier output rather than the Vav (2Vm /π) is to give the DC equivalent for the same power as the rectifier output is a complex waveform.
  5. gurse

    Full Wave Bridge Rectifier Circuit

    Why do you need the coil to have enough inductance please, is it because of its filtering effect.
  6. gurse

    Full Wave Bridge Rectifier Circuit

    So what is the correlation between AC and DC voltages that I measured across the coil in your opinion.
  7. gurse

    Full Wave Bridge Rectifier Circuit

    DC current was measured in series with the coil and the AC and DC voltages across the coil. In fact, Also, I have measured the AC current and it was 2.54 A. Both were measured with a multimeter changing modes between AC and DC. I was only interested in DC current to the coil but also measured AC...
  8. gurse

    Full Wave Bridge Rectifier Circuit

    Hi itsmoked, My sketchy maths check, The Vrms of a full bridge rectifier output is Voltage peak / √2 and the peak voltage of an Vrms = Vrms * √2. Therefore, 110V Ac rms input to a full bridge rectifier will yield 110V rms at the output, 110 * √2 / √2. Hi IRstuff, The reason why raised the...
  9. gurse

    Full Wave Bridge Rectifier Circuit

    I have a full wave rectifier thyristor control circuit on a 10 Ohms resistor coil which produced the following results with 240V AC rms. DC Current through coil (A) DC Voltage across Coil (V) AC Voltage across coil (V rms) 1.15 10.8 92.0 2.43 22.5...
  10. gurse

    PWM Circuit

    if you measure the outputs A and B of a pulse width modulation circuit at zero duty cycle, it will measure equal voltage at A and B outputs with the same duty cycle with respect to ground resulting in 0V. What will the output will look like please if measured between A and B outputs please.
  11. gurse

    Electric Motor Heater

    Having re-considered the options suggested, i will use a diode and a resistor in series with the heating element. Heater 110V 40 W I = 40 / 110 = 0.36 A Heating element resistance = 110 / 0.36 = 305 R Diode will reduce the 240 rms to 240 * 1.414 / 2 = 170 V rms A 300 R resistor in series with...
  12. gurse

    Electric Motor Heater

    Calculations rule out using a diode so I will go ahead and use a resistor in series with the heater coil as planned originally and waste some energy in the process.
  13. gurse

    Electric Motor Heater

    Hi Itsmoked, The way I look at it was as follows, Vdc across the heater coil is 240V rms * 0.45 = 108 through a diode (half wave rectification). Current across the heater coil is V/R = 108/302 = 0.36A and power = I^2 * R = 38.6 W. Therefore, 110V AC directly or 240V AC through a diode will...
  14. gurse

    Electric Motor Heater

    Hi Keith and Waross For a half wave rectifier Vdc = 0.45Vrms = 240 * 0.45 = 108 V DC Effectively, the voltage across the heater will be the same as applying 110V AC so the power will be almost the same (110V 40W) whether you apply 110V AC directly or 240V AC through a diode.
  15. gurse

    Electric Motor Heater

    Considering all the options suggested, I have decided to use a diode in series with the heater.
  16. gurse

    Electric Motor Heater

    Thank you for your replies but I would like to use an appropriate power rated resistor, any comments on use of resistor please.
  17. gurse

    Electric Motor Heater

    I have a 7.5 kW motor with 110V, 40W anti condensation heater. But i have only 240 V supply for the heater, can I put a resistor in series with the heater to reduce the voltage please.

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