What is meant by stalling of motor?

Stalling is a condition at which a motor stops rotating even when there is sufficient voltage at its terminals. This condition occurs when the torque required by the load is more than the maximum torque (Breakdown torque) that can be generated by the motor. At this condition, the motor drains the maximum current and the speed comes zero.

stalling of motor - Induction motor Torque-Speed Characteristics
Induction motor Torque-Speed Characteristics

DC Motor Torque speed Characteristics

Every motor is designed to spin a particular amount of load. When the load is further increased above its overload region, the speed of the motor gradually reduces and the motor stalls. The Slip during stalling of a motor is 100%. Since the motor is not rotating, there will be no back EMF and so the power consumption will be the maximum.

Reasons for stalling of motors:

1. Electrical reason: Missing out of one phase (two phasing) or single phasing of input supply
2. Mechanical reason: Rotor jam, overload or load unable to move.

Stall Current

Stall current is the current drawn by the motor at locked rotor condition. It is the highest current a motor can draw and is proportional to its rotor resistance. If stall current is drawn by a motor for a longer time, motor gets overheated causing damage of winding.

Stall torque

Stall torque is the load torque at which the motor shaft stops rotating. It is also known as locked rotor torque.

Stall torque - motor stall
DC Motor Torque speed Characteristics

Related Searches
• Induction Motor Stalling
• Motor Stall Protection
• Motor Stall Fault
• Motor Stall Current
• Safe Stall Time Of Motor
• Motor Stall Torque Calculation
• Maximum Continuous Stall Torque
• Locked Rotor Protection Relay

This Post Has 7 Comments

  1. Ganesh

    Stalling of motor is well explained here. I was searching for the right explanation for quite long time untill I found one here. Now I know what is stalling of motor.

  2. Adam

    When the load torque requirements cannot be fulfilled by the motor, motor stalls.

  3. reza

    so what is the maximum stalling time that mentioned in the specific data sheet of the motor?
    for example :
    maximum stalling time 7.5/4.1 s (cold/warm)

  4. Vaman

    why does the mechanical cause of Rotor jam occur? How can we reduce it?

    1. Electrical Classroom

      Two major reasons for motor jam are Electrical overload and accumulation of solid particles, chemicals, dust and dirt in the motor bearings.

  5. Andy

    Motor stalls from tone arm drag on record. Can not counterweight tone arm. Armature is the turntable. Possibly remedys?

  6. Sourabh Hajra

    How to detect the stall of an Impedance Protected AC fan with rated current 0.08A ? Current not increasing when it stalled

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