A student observed a specimen from the root of a common
January 31, 2026Activity Description–Unit 10 This link will take you
January 31, 2026A 125 V, 5 kW, 1800 rpm dc shunt motor requires only 5 volts
A 125 V, 5 kW, 1800 rpm dc shunt motor requires only 5 volts to send full-load current through the armature when the armature is held stationary.
(a) Determine the armature current if full-line voltage is impressed across the armature at starting.
(b) Determine the value of the external resistance needed in series with the armature to limit the starting current to 1.5 times the full-load current.
(c) The motor is coupled to a mechanical load by a belt. Determine the generated voltage at fullload condition (Vt = 125 V, n = 1800 rpm, Ia = Ia(rated)). If the belt breaks, determine the speed of the motor. Neglect rotational losses and assume 10% reduction of flux due to armature reaction at full load.