DC Motor failed to run on load

In summary: Is it a shunt or series field supply?How many watts does the conveyor require?Can the motor deliver more watts out of its shaft than it receives in the wires from its supply?
  • #1
leendabests
3
0
Hello,

Im using DC motor to run the conveyor but suddenly the armature shows high current 130 A for 30 V power and the speed can't increase anymore. The motor power stated in the name plate is 93.8 KW, Armature voltage is 453 V and Armature ampere is 225 A. The motor can run free load after disconnected from the load but fail to run on load. We have checked the field coil, armature coil and the brushes . The are no insulation damaged since it can be run free load.

What are the possible causes to the motor that fail to run on load? Is it because not strong magnetism or another mechanical failure?
 
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  • #2
sounds to me like the electrical supply is not stout enough to maintain voltage when it's loaded to as little as 30 amps.
130 volts at 30 amps is how many watts?
How many watts does the conveyor require?
Can the motor deliver more watts out of its shaft than it receives in the wires from its supply?
What do you have powering this motor?

old jim
 
  • #3
It is 30 V 130 A... The actual armature voltage is 453 V. But when the voltage reaching only 30 V the armature current already 130 A. The the armature stop to rotate.
 
  • #4
leendabests said:
Im using DC motor to run the conveyor but suddenly the armature shows high current 130 A for 30 V power and the speed can't increase anymore.
This is a motor that has been operating satisfactorily in this task for a long time? Then suddenly it has stopped turning under load, and you have made no changes in the motor's controller nor the conveyor?

How did you check the field coil? I'm thinking that a short in the field would still show continuity, yet give a major reduction in torque. How to reveal this? Maybe if you could give it rated field current, and as it warms up use an infrared camera to monitor the temperature of the outside casing, you might find an ominously cool area indicating no heating underneath.
 
  • #5
The rated armature current is 225A. Why are you stopping at 130A (at 30V)?? Keep increasing the voltage until you get 225A, if that don't give you enough speed (or any speed at all) then we can say something is wrong.
Its normal for DC motor to consume large current when stalled or during starting. It is also normal for it to consume rather large* current when applied with rather small voltage than rated, because this results in not enough power being developed and motor either refuse to starts or rotates very slowly.
*large in the sense of ratio of Applied Voltage/Current.
 
  • #6
300px-Carbon_brushes.jpg



Just sayin'
 
  • #7
an open field results in high armature current and virtually no torque.

is it series or shunt field?
 
  • #8
The voltage stopped at 30 V only and can not increase anymore. And the current showed 130 A at that time.. The motor is in series field.
 
  • #9
leendabests said:
The voltage stopped at 30 V only and can not increase anymore. And the current showed 130 A at that time.. The motor is in series field.

Can you please give some details of what type of supply is being used to power the motor.
 

Related to DC Motor failed to run on load

What is a DC motor?

A DC motor is an electrical machine that converts direct current (DC) electrical energy into mechanical energy. It consists of a stator, which provides a stationary magnetic field, and a rotor, which carries the current and experiences the mechanical force that produces the motion.

Why would a DC motor fail to run on load?

There are several reasons why a DC motor may fail to run on load, including:

  • Insufficient power supply: If the motor is not receiving enough voltage, it may not be able to overcome the load and start running.
  • Mechanical issues: If there is damage to the motor's bearings, gears, or other components, it may not be able to generate enough torque to run on load.
  • Electrical faults: Faulty wiring, connections, or components can prevent the motor from receiving the necessary current to run on load.
  • Overheating: If the motor is operating at a high temperature, it may not be able to function properly and fail to run on load.
  • Excessive load: If the load on the motor is too heavy, it may not have enough power to overcome it and run properly.

How can I troubleshoot a DC motor that fails to run on load?

To troubleshoot a DC motor that fails to run on load, you can try the following steps:

  • Check the power supply: Make sure the motor is receiving the correct voltage and that there are no issues with the power source.
  • Inspect the motor: Check for any mechanical damage or issues that may be preventing the motor from running on load.
  • Test the electrical components: Use a multimeter to test the wiring, connections, and components for any faults.
  • Reduce the load: If the load is too heavy, try reducing it to see if the motor is able to run properly.
  • Allow the motor to cool down: If the motor is overheating, turn it off and allow it to cool down before attempting to run it again.

Can a DC motor be repaired if it fails to run on load?

In some cases, a DC motor that fails to run on load can be repaired. It will depend on the cause of the failure and the extent of the damage. If the issue is with the electrical components, they can often be replaced or repaired. However, if there is significant mechanical damage, it may not be possible to repair the motor and it will need to be replaced.

How can I prevent a DC motor from failing to run on load?

To prevent a DC motor from failing to run on load, you can take the following precautions:

  • Ensure the motor is receiving the correct voltage and power supply.
  • Maintain the motor and its components regularly to prevent mechanical issues.
  • Make sure all electrical connections and components are properly installed and functioning.
  • Avoid overloading the motor and ensure it is only used within its recommended parameters.
  • Allow the motor to cool down if it is operating at a high temperature.

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