Thank you CataM.
"The answer to your question is yes, if and only if the "Kt" constant is the same. " OK.
...Because as you correctly guessed, the field winding does consume power.
Was not a guess, it is a fact; the stator field does consume electrical power. A magnet does not.
But you have some concepts wrong. For brushed DC Motors, the field is always the stator.
I did not state otherwise.
schmitt trigger;1597433 If the permanent magnet is in the stator said:
This motor does not run on its own[/B], it requires to be driven by an electronic circuit.
The losses of the electronic circuit have to be factored into the overall efficiency calculations.
An older outboard starter motor has a stator winding; a newer model replacement motor has permanent magnets. Both are still plain brushed motors, none a BLDC, and run on its own. There is no electronic circuit to drive any other than a battery.
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Now, another thing difficult for me to express in proper words : A permanent magnet instead of a field winding saves the power consumed by the winding.
The lesser electrical power consumption raises the efficiency of the motor; efficiency as a ratio of mechanical power exerted to electrical power inputted.
Is it wrong to say that a magnet contributes with some 'pseudopower' to the motor operation ? (The power now
not consumed by the stator field )
If the permanent magnet was weak; would the motor yield a lesser mechanical power ?
If the magnet was stronger, would the mechanical output power become greater for the same electrical power supplied ?