How speed control of DC motor can be achieved?

How speed control of DC motor can be achieved?
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1 Answer

Answer :

Induced emf in the armature E = P * φ * Z * N / A * 60 volts.
Where Z and A are constant.
N ∝ Eb / φ
N ∝ V – Ia ra / φ.
We can consider that the Ia ra drop is very small and there by in the place of V – Ia ra
we can consider only V. If it so then N ∝ V/ φ.
So speed may be varied by varying either applied voltage to the armature and by
varying field flux or field strength per pole or total field flux.
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