Why is Dc shunt motor is not used to start at heavy load?

A DC shunt motor is not used to start under heavy load because it has a relatively low starting torque. At startup, the armature is stationary, leading to minimal back EMF and high armature current, which can cause excessive heating and potential damage to the windings. Additionally, the field current is constant, which does not provide the necessary torque boost needed for heavy loads. Consequently, other motor types, like series motors, are preferred for heavy load applications at startup.