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  1. mohpower

    variable torque VFD - IGBT over temperature problem

    the 57 Deg C is the heatsink temperature. at this temperature the drive is runninig (no tripping). we are thinking to add more fans to get the hot air out. we found dust also inside of the MCC, we will need also to clean the heatsinks. Regards
  2. mohpower

    Soft start issue

    Hi everyone, As I understand the problem, the soft-starters, motors, and pumps start and run normally. Intermittently, as the pump is turned off the Soft-Start trips on a fault code for "faulty power module" with a secondary possible problem of "faulty unit". The system uses a 600:120 V PT...
  3. mohpower

    variable torque VFD - IGBT over temperature problem

    Hi everyone, the VFD is a 200HP Contant Torque used to run a 250 HP fan (considered as variable torque). Yesterday, i took the following measurements at full load(VFD running without tripping). - currents : ph A: 255 Amps, Ph B: 252 Amps, ph C: 254 Amps -motor power was at: 90.6 % -motor...
  4. mohpower

    variable torque VFD - IGBT over temperature problem

    I don't know the temperature inside the MCC. I will record it this week and letr you know then. thank you
  5. mohpower

    variable torque VFD - IGBT over temperature problem

    the VFD is mounted inside an MCC.
  6. mohpower

    variable torque VFD - IGBT over temperature problem

    Thanks for your answers, The FLA of the motor is 270 amps (460 VAC, PF=0.9). the load is a fan, so it is a VT and 200 HP drive is supposed to handle it. if the problem is due to cooling, then phase B is the one which has to get the overtemperature?
  7. mohpower

    variable torque VFD - IGBT over temperature problem

    Hi everyone, I have an issue on 200 HP variable torque VFD driving a 250 HP fan. the issue is the phase B IGBT inverter that goes to overtemperature that causes a VFD tripping. at the beginning we thought the VFD was faulty then we replaced with a new one. the same problem appeared in the...
  8. mohpower

    Help!

    you mean rated power: Rated power is the power to which the motor is made to operate. in the nameplate of the motor you find the value of this power (say 20HP ....). the absorbed power or the load power is the power demand from you load it varies depending on the load .... hope this will help...
  9. mohpower

    power factor penalty

    you might find some information in this link http://www.progress-energy.com/custservice/carcig/resourcectr/presentations/power_factor_final.pdf thanks
  10. mohpower

    Power/Energy Question

    you are right jghrist when you said "Vrms² does equal Vdc² + Vac_rms²" what I said is also correct "Vrms^2 doen not equal Vdc^2 + Vac^2" because i was refering to instantenous values. best regards
  11. mohpower

    Power/Energy Question

    Zacky when you try to find the power consumed by the resistor you have to find the RMS (root mean square) value of the current and the voltage applied to it. P = Irms * Vrms = Vrms^2/R = Irms^2*R the formula you gave is not correct because Vrms^2 doen not equal Vdc^2 + Vac^2. there is also...
  12. mohpower

    Power/Energy Question

    I think I made mistake the right answer is as follows: the root mean square of the total currents applied to the resistor is not equal to the individual RMS of each current but you have to find first the total instant currents and then you derive the RMS value of it. Irms= sqrt (1/T...
  13. mohpower

    Power/Energy Question

    the current applied to the resistor will be: Imax/sqrt2 + Idc= 1/sqrt2 +10 = 10.707 amps. the power for 1 ohm resistor will be: R*I^2 = 1*(10.707)^2 = =114.6 watts regards
  14. mohpower

    Motor inertia information

    C2sco, i think you need to contact the manufacutrer to get you the data. you cannot find them in the nameplate of the motor. the mass of the rotor is not in the nameplate ...which software are you using for this study. can you send us what exactly what is required by the software?. thank you
  15. mohpower

    duty cycle to voltage or current converter

    hello everyone, could you please inform me if is there any device that converts duty cycle to an analogue voltage or analogue current. thanks www.ierltd.com
  16. mohpower

    omron plc to remote area with fibre optic transmission

    hi thank you for the feed back I am getting. Well I would like to use omron plc and at the same time I do have some (100) input/output 200 m far from the site i wonna use remote device but at the same time I have to use fibre optic transmission so if some has an idea about these. thanks...
  17. mohpower

    Difference between Allen Bradley and Omron ?

    hi, the aspects are how address inputs and outputs (discrete and analogue) thanks www.ierltd.com
  18. mohpower

    Difference between Allen Bradley and Omron ?

    Hi I was working with allen bradeley plc now I am switching to Omron PLC is there any one who can help me in this transition.? Thanks for your help in advance www.ierltd.com
  19. mohpower

    omron plc

    Hi, I would like to know about Omron plc specially who to program them (I know for allen Bradley we use rslogix and for Omron we use what program?) Thank you. www.ierltd.com
  20. mohpower

    "emergency" generator vs. battery E-lighting

    Hi ScottyUK yes Euro-diesel rotary UPS is bought by GE. regards

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