Electric Motor Tripping Reasons and How to fix them, Star Delta Motors

Electric Motor Tripping Description:

Electric Motor Tripping

Electric motor tripping reasons and how to fix them- The electric motor tripping may be due to a couple reasons, it may be due to the circuit overloads, short circuits, ground fault surges, low resistance, over-heating, contamination, vibration, cable/wire is cut, due to the motor direction clockwise or anti-clockwise, timer settings, breaker rating, fuse, cable insulation, due to the wrong values selection in the HMI or SCADA system used to control an electric motor, or power supply etc.

So, this article is all about how to find the reason of electric motor tripping, and then how to easily fix the issue. I will share with you 10 easy to follow steps which can be used to find the problems that cause the electric motor tripping. These tests apply to all types of the electric motors.

Without any further delay, let’s get started!!!

Needed Instruments for the Electric Motor Troubleshooting:

To find the issue/problem/cause of electric motor tripping, you should have some instruments and test equipments. Apart from the screw drivers, pliers, etc following are the test equipments which you will need.

  1. Digital Multimeter
  2. Electric Tester
  3. Insulation Tester
  4. Megger Tester

Before, I am going to explain how to find the cause of electric motor tripping, there are a few things, that I believe you should know, so that you can easily understand the whole picture.

No matter which type of the electric motor you pick from the market, every electric motor has a predetermined life span which typically ranges from 30,000 to 40,000 hours, this information is usually provide in the electric motor catalogues or datasheet. This life span of the electric motor depends on the proper maintenance, without which they are likely to break down much quicker.

You know very well about the electrical circuit breakers, because these are the type of electrical devices which are commonly used in house, building, industries, etc. an electrical circuit breaker is used for controlling and protecting the electrical power system, and the electrical devices connected to it. Circuit breakers can be operated manually and automatically. So, an electrical circuit breaker is the main device that protects your all electrical devices and machines because it trips when too much electricity flows through it or when it cannot handle the excess current load. The electrical circuit breaker cuts off the electricity to keep your circuits from overheating or causing more damage. Imagine the situation, if there is a short circuit or overload current and there is no circuit breaker trips, then fires would have been quite common issue.

No doubt the tripping of the circuit breaker ensures safety, but it can get quite frustrating, if the circuit breaker constantly start tripping and getting the power back on repeatedly. This tripping of the circuit breaker may be due to some issues, so the reason behind the constant tripping should be find out and fixed.

Why Tripping Problem:

Engineers and technicians working in different industries, manufacturing companies, electrical power companies, or water treatment plants or irrigation etc, face many problems regarding the electrical motors. These problems may be at a small level or high level, the electric motor tripping may be due to wrong connections or may be due to the wrong timer settings, or may be due to the weather changing like the hot weather, due to which the circuit breakers keep tripping. This can also be due to the wrong selection of the circuit breaker, wires, or contactors, which do not fulfill the basic requirement of the electric motors and as a result the electric motor trips.

How to find the problem:

By going through the entire following tests, you can easily find the reason behind the electric motor tripping, and once the reason is known then fixing the problem is mater of few minutes.

  1. Check the continuity of the cable using Digital multimeter (how to check cable continuity).
  2. Check the direction of the motor clockwise or counter-clockwise.
  3. Check the timer setting values for time and rated current.
  4. Check the relays, if connected with star delta connection and if overheating according to weather or motor over current or due to reverse direction of the motor
  5. Check the motor from down side, if submersible motor
  6. Check the breaker rating size if less.
  7. Check the setting values for the motor from HMI screen, if connected with HMI and PLC.
  8. Check the fuses if connected in Star Delta connection.
  9. Check the insulating of the cable.
  10. Check the power supply.

How to Solve the Problem:

Now, I am going to explain each one in detail, if you carefully read all the following steps, I am sure you will be able to fix the electric motor tripping problem.

1) Cable Continuity Test

In this step, the engineers or technicians should check the cable continuity by using a digital multimeter. This is really an important test, because with the help of this test you can easily find, if the cable is cut, or if the wires or short together. You check the continuity of each wire/cable for this you can set the digital multimeter on beep. If the cable/wire is not cut you should hear a beep sound, which is a signal that the cable is ok.

If the cable is long and you are not able to connect the multimeter leads with the starting and ending points of the cable/wire then you can connect a 10k resistor at the end points and then at the starting points you can set the digital multimeter at the resistance. If you can read the value of the resistor, then the cable is ok and you can start the motor if there are no more problems in the motor.

Electric Motor Tripping

2) Motor Direction Test.

In this step engineers or technicians can check the motor direction, if it is clockwise or counter clockwise. If counter clockwise, it means the motor is not working in good condition due to which the electric motor will overheat and with the passage of time may lead to the permanent damage of the electric motor. Because of the wrong direction the water or other liquids pressure will be low. So this type of problem can be fixed by changing any of the two wires from the motor terminal connection in the panel box. But if the motor rotates in clockwise it means the motor is ok. This can be confirmed from the water/liquid pressure. So, good water pressure ensures that the motor is working in good condition.

Electric Motor Tripping

In this picture you can see water pressure is good it means the motor is working in good condition so no need to change the wires.

3) Timer Setting.

If your motor is connected with a timer for protection purpose you will need to check the timer setting value, if the time value is ok and still the electric motor is tripping then you should check your motor rated current from the motor name plate e.g if your motor current is 5A, then all you need is simply set the current value in the timer 5A using minus tester screw driver.

Electric Motor Tripping

But keep in mind that never increase the current setting value above rated current because, if you select a greater value, there will be more chances of motor damaging. Also you can check the motor relay connected, if tripping due to hot weather or not working properly then change you can check with hand touch if the relay is hot then change.

4) Submersible Motor.

If the type of electric motor you are using is submersible (Submersible motor is the kind of electric motor which is dipped in water or any other liquid) and constantly tripping, then you will need to make sure that the water or liquid is clean. When a submersible motor is used for the waste water management, there are high chances of tripping due to the wastes present in the water. When a plastic or something else get stuck inside the motor, the motor will trip the breaker, because while the motor is running in normal condition and if something stuck inside it, the motor will need more force due to which it can overload, which leads to the electric motor tripping. In a situation like this if there is no electrical circuit breaker the motor will damage in a minute or so.

Electric Motor Tripping

5) Circuit Breaker Rating.

Circuit breaker and contactors are used for safety and protection purposes. Once you buy an electric motor, and you know about the motor specifications, a control and safety circuit can be easily designed. You can order a circuit breaker as per the motor rated current. It’s a good designing practice to add 10% more, because sometimes motor current exceeds the rated current when you turn ON the motor, so its good to keep the current little more than the electric motor rated current. If the motor is still tripping, then you can perform the above or below tests. If everything is ok and the breaker still keeps tripping then you have no other option than changing the circuit breaker.

If your motors are connected with PLC and HMI or SCADA you can check the setting values from the HMI or SCADA if the process values or any setting values are less or higher than motor rated size then change the values from HMI or SCADA.

Electric Motor Tripping

6) Electric Motor Star Delta Connection.

If your motors are connected in Star Delta connection or only Star connection or Delta connection and they are connected with electric fuses for more safety or protection purposes and if the fuses are blown then change the fuses to new one. But how you will know about the fuses if they are ok or blown? First take a multimeter and set the digital multimeter knob on the ohms or continuity. Connect the test leads of the digital multimeter with the opposite ends of the fuse. if you hear the beep sound it means the fuse is ok no need to change the fuse. But, if you don’t hear the beep sound or if you don’t see any value on the digital multimeter then it means the fuse is blown and it needs to be replaced.

Electric Motor Tripping

7) Insulation test.

Checking the insulation of the cable is also most important test, because sometimes when the weather changes from cold to hot the cable becomes more hot, due to which it may lead to the electric motor tripping, this may also due to the exceeded current, when the current crosses the rated value, the cable gets hotter. So this is the responsibility of the design engineer to select proper cable size with good insulation to ensure the normal operation of the electric motor. And for checking the insulation of the cable you can use the megger tester for checking the insulation of the cable.

Electric Motor Tripping

In the above picture you can see clearly the megger insulation tester this picture shows clearly how to do the megger testing of the cable.

8) Power Supply.

This is another most important test, you should know about the electric motor technical specifications. You should know the motor you are going to use is a single phase or 3 phase. You should know about the rated voltage and rated current. If the source voltage is greater than the rated voltage of the electric motor, then there is no doubt about the breaker tripping. So, if the supplied voltage is less or more this will lead to the electric motor tripping. The rated supply is always mentioned on the motor name plate, if single phase motor then connect single phase voltage(210V-230V), or if three phase motor then supply three phase voltage(400V-450).

So that’s all about the electric motor tripping causes and how to fix them. I have you have learnt something new from this article. You can also watch a video tutorial by Engr. Abdul a good friend of mine. Don’t forget to subscribe to his channel.

Watch video:


Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...

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