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  1. #16
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    Yep I hear you Albert, that’s fine at install but it’d be nice to have accurate info from the seller...there is my naievety again.

    That is a big damn sander.

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  3. #17
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    Jun 2005
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    Quote Originally Posted by Austin_Turner View Post
    And here is me naively thinking that machine electrical plates would have to denote something like the wiring configuration as a standard
    Any recent motor from a reputable supplier such as Felder, Minimax etc (generally European) will be what it says. The ramifications of that not being the case are huge.
    CHRIS

  4. #18
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    Thanks Chris, and I assume from what bob said and the plates I have seen that will mean star configuration except if delta is explicitly stated?

  5. #19
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    The plate gives the configuration of the connections for either type, what the motor is currently configured to can only be ascertained by visual inspection.
    CHRIS

  6. #20
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    Alexandra Vic
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    Quote Originally Posted by BobL View Post
    Nope on the torque.
    HP = torque x rotational speed .
    A SP motor producing 1HP at a nominal RPM MUST be producing the same torque as a 3P motor producing 1HP at the same RPM.
    My understanding and experience is that 3ph motors have more starting torque than 1ph motors of equivalent power. In situations where the motor must start under load this is an advantage and can reduce start times and peak start currents. However, this advantage is obviously negated if the motor is powered by a VFD configured for slow starting. The issue with starting 1ph motors is that they need to create an artificial phase via start winding and capacitor in series to determine direction of rotation and supply a kick start to start the motor in the correct direction. While this will start the motor, it does not do so as efficiently as a 3ph supply does, so the motor generally takes longer to achieve rated speed under load, and so draws its peak starting current for longer.

    Once running at speed, a 1ph motor and a 3p motor from the same manufacture and with the same rated power and speed should be able to produce very similar torque into the same load. Note however that motors only produce enough torque to meet the load requirements, and may rarely or never supply their rated output power. The power rating relates to the ability to operate continuously or within the rated duty cycle without overheating or otherwise damaging the motor.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

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