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  1. zacky

    Power Rating Calculation

    stevenal, agreed with your calculation that the PF of this circuit is .707 so. at the transformer's secondary side the power delivered to the circuit will be Irms.Vrmsx(.707) Now what will be the exact tranformer's rating: Is it the product of Irms.Vrms Or the real power it delivers Irms.Vrmsx(.707)
  2. zacky

    Power Rating Calculation

    JBinCA, Thanks for the detailed explaination. I still have one point is not clear.If the load is pure resistive,that means that the current and voltage are in phase and the power consumed by the load is real power,so if we calculate the power at the load should equal the power deliverd by the...
  3. zacky

    Power Rating Calculation

    Actually, I did two calculations: one at the load and the other at the transformer secondary. The two calculations give different results. No measurments are taken- Just mathematical calculations and neglect any losses.
  4. zacky

    Power Rating Calculation

    This ciruit is very simple : single phase transformer , its secondery is connected in series with a single diode and resistive load( simple half-wave rectifier) The DC power Wdc = Idc x Vdc -- average values of the rectified voltage and current. If you calculate the transformer's secondary VA...
  5. zacky

    Power Rating Calculation

    We can use the following formulas for the instanious current and voltage: (Esin x /R) and (Esin x) ,multiply them together and ,make the integral over one period cycle and devide over the period cycle and that would be the wattmeter reading( the mean value of the product of current and voltage)...
  6. zacky

    Power Rating Calculation

    A single phase transformer is feeding a half-wave rctifier with a resistive load across it. What is the real value of the power cosumed in the resistor load( dc + ripples ),is it to : - Multiply transformer's secondary rms values of the voltage and current- assume 100% efficiency. -Or to mutiply...
  7. zacky

    Power/Energy Question

    So,I understand that my equation should be corrected to: Power=(Vdc+Vac_rms)'2/R And the superposition theorem does not apply for power. Is that what you mean ?
  8. zacky

    Power/Energy Question

    Thx for reply Is that mean to measure the power by DVM we have to make 2 measurments across the resisor : Vdc and Vac ,and then the power will be: (Vdc'2 + Vac'2)/R Regards
  9. zacky

    Power/Energy Question

    A 10 amp DC current is passing through 1 Ohm resistive load, so the power consumption by the resistor is 100 Watt. Now, a sinusoidal ripple current of 1 amp peak is superimposed on the top of the DC current, then the average current is still 10 amp. My question now : Is the resistor still...
  10. zacky

    AC Motor speed & direction control

    Sorry for the delay.I noticed that during the spin cycle the"BRAKE/CLUCH" solenoid is energized and pulling the arm of brake and preventing the motor from spinning. Now I disconected one of the wires going to "BRAKE/CLUTCH" solenoid and now it is de-energized and the machine spins BUT AT LOW...
  11. zacky

    Motorola M68HC05PGMR-2 Programmer

    I have the Motorola programming board MC68HC05PGMR-2 but without the software needed to operate it. Any one can direct me to a website to download the software needed for that programmer ?
  12. zacky

    AC Motor speed & direction control

    well itsmoked,so could you please how that cluch/brake works ? is it mechanical system ?
  13. zacky

    AC Motor speed & direction control

    Thanks for your great help. Also I noticed in the machine schematic a coil named " BRAKE/CLUTCH" what that coil for ?
  14. zacky

    AC Motor speed & direction control

    Please, could some one explain how the Wash Machine's AC Motor ( with capacitor on it )speed and direction controlled ? During the wash cycle, the motor rotates back an forth at low speed, while at spin cycle rotates at very high speed. My question is how during the wash cycle the motor's speed...
  15. zacky

    Magnetic Coil

    Thanks nbucka, so if we are going to wind bifiller centre tap secondary winding of a transformer, we can start with the centre tap and continue till we end up with two terminals. one will pass the centre tap ( N+.1} and the other terminal will end just before the centre tap (N-.1}. Can we call...
  16. zacky

    Magnetic Coil

    A magnetic coil consists of 24.9 turns ( the last turn is not fully complete). Is this coil of 24 turns or 25 turns ?
  17. zacky

    FET's Issue

    Warpspeed, another question please, when it will be a good idea to use Foil coil istead of Wire coil ? Also, regarding to the wire coil, if all the turns of one layer are shorted together, but we have a good insulation between each layer,does that affect the transformer operation?
  18. zacky

    FET's Issue

    Warpspeed, I can see your wide range experience includes ferro-resonant transformers. If you don't mind, could you please point me to a good reference book about ferro-resonant transformer design.
  19. zacky

    FET's Issue

    Warpspeed, 15 years ago, 500W was the maximum power could be obtained from flyback supplies, what you think about the maximum limit today ?
  20. zacky

    FET's Issue

    fsmyth, how simple resistor/cap combination can do the commutation task ? Do you mean by using SCR's with turn off gate?
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