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Recent content by MerleH

  1. MerleH

    Single pump control via VSD from multiple PID's...

    Yes, you have the basic concept. Simply switching the PID setpoint will be a lot easier than coordinating two PID loops.
  2. MerleH

    motor power factor

    Yes, of course, the power factor of a resitive load is one. Also I said the tangent of the phase angle when I should have said the cosine.
  3. MerleH

    What do you use for Application Dev. in Excel

    I sometimes copy critical formulas to another sheet which I than hide from the user. I than write a VBA routine to copy these formulas where they belong. If, for instance, you want the user to be able to add as many rows as he wants, but want to make sure the formulas update the way they...
  4. MerleH

    motor power factor

    You are close. Actually, motors are not close to pure inductive loads, but are close to pure resitive load. A pure resistive load has a power factor of zero. That means that all of the current is in phase with the voltage. Motors however have some inductive loading. The inductive loading draws...
  5. MerleH

    electric supply to fire water pump

    As has been pointed out, the 1200A MCC is not adequate for a 1500A locked rotor current on a fire pump. Also, if the MCC is downstream of the service, you will need a second source of power. You might want to consider a diesel driven fire pump as an alternate. This would eliminate all of the...

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