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  1. elmotor

    Running an induction machine beyond rated frequency

    I would say that with 1 HP motor, identical bearings are mainly used for both 1800 and 3600 RPM motors not lubrication interval is not the issue as bearings for this size of motors are greased for life and there is possibility to re-grease the bearings.
  2. elmotor

    Grease: Positive Lube System / Flow-through Lube

    This kind of lubrication arrangement has also been used in bigger motors from ABB and also in the past in Stromberg motors. Here the grease is not going through the bearing but only greasing the "outer" side of the bearing. With this arrangement the bearing temperature rise can be maintained...
  3. elmotor

    50/60 Hz Motor Selection

    Well, running a motor test laboratory more than 25 years in one of the biggest motor manufacturers in Europe, this is my experience where theory and practise are daily met. Regarding the voltage, I understood so that the line voltage is 400V and the motor is rated to 380V, so if there 400V...
  4. elmotor

    50/60 Hz Motor Selection

    Yes you are correct and as in your graph up to so-called field weakening point (380V@50Hz), motor will work in the constant torque area and the power will increase in proportion of the speed. After this point, motor will work in constant power area and produced maximum torque will decrease in...
  5. elmotor

    No load current on a motor

    For your question "Is there a rule of thumb for estimating no-load current on a motor?", Zlatkodo's genearl estimates are reasonable for "standard" enclosed motors. In case of open type motors as IP23, induction is often designed to be higher and thus the saturation of iron is a lot higher. In...
  6. elmotor

    Overtorque at short circuit conditions?

    I would say that the spec does not make sense in VFD, but for the net supply as the spec seems to be written for that. If the short circuit happens on the motor terminals, the drive will try protect itself (IGBT's) with fast overcurrent protection and will not create high torque.
  7. elmotor

    Overcurrent effect for motors

    It seems that the manufacturer would like to stay on safe side, giving this 108 % at 30C. I mean that the temperature rise will be appr. 90K in case that at nominal load it is 80K, for what I have some doubts. Usually this size of 4-pole motor have temperature rise well below 80K, depending on...
  8. elmotor

    dynamometric testing for AC& DC electric motors

    Petronila, you wrote "Specific needs are for prove efficiency at some loading conditions in a motor repair shop". As you probably know there different standards for determination of efficiency mainly as IEC or IEEE, so should you follow these ones or simply the efficiency "input/output"? If...
  9. elmotor

    Motor rating for VFD

    Oops, because it was my first time in this forum, it happened as for young men... for sure you know what I mean. Additionally pay attention in cabling and grounding to avoid bearing currents.
  10. elmotor

    Motor rating for VFD

    Your drive 30 kW, giving maximum nominal output current of appr. 60A, which determines your maximum load. Why would you like to use 37 kW motor? I think that stator winding temp. rise is not a problem and you are not in Ex -area? Consider following things: 1. Constant or quadratical torque 2...

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