Working of motor----------ABCD be in a horizontal position when the keys switched on the current will be flow and the coil ABCD through brush X and throws back to the battery via split ring by applying Fleming's left hand rule we get that no force acts on Arms BC and AD as they are parallel and a b experience a downward force and CD experience upward force while rotating the coil it reaches the vertical position and the brushes close contact with the splitting but when the coil passes through the vertical position then the rings automatically changes their position and the force on right hand side is always upward and force of left hand side always down ward

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