How To Test Brushless Motor With Multimeter

How To Test Brushless Motor With Multimeter? [A Complete Guide]

Noticing some issues regarding your brushless motor lately? Maybe whenever you connect it to the main circuit, it doesn’t rotate. If you want to fix this without opening the mounting, you need to test the motor first.

But how to test brushless motor with multimeter?

First, put your multimeter in line with the brushless motor. As brushless motors are DC, set that option on the multimeter. You’ll have to line in the multimeter with the motor. Then take the reading of the voltage, resistance, and amperage with the probes.

This was just a short briefing on checking the motor. You have to go through the details to know the full motor checking procedure.

So read along if you want the details!

What Can We Know About a Brushless Motor from a Multimeter Reading?

You can tell if your motor is working fine or not with the help of a multimeter. You might need professional help to fix your brushless motor. 

But a multimeter helps you to detect where the problem actually is and what is needed to be fixed.

It’s possible to find out many brushless motor problems with a multimeter reading. This includes motor winding problems, power supply errors, insulation issues, and so on. The readings determine the condition of the motor health.

How to Use a Multimeter for a Brushless Motor?

Using a multimeter is very easy. To test if your brushless motor is completely fine or not, you have to take some readings. 

First, set the multimeter on DC mode as brushless motors are DC motors. Then Plug in the Common probe known as the “com” probe to the black-colored jack. You need to change the red probe depending on what your reading will be.

You can know the voltage, amperage, and resistance of your motor with a multimeter.

Compare your reading with the ideal reading numbers and detect the issues by yourself.

How to Test a Brushless Motor with Multimeter: 4 Simple Steps

It is good to test a brushless motor regularly and keep a track of its performance. With a multimeter give your brushless motor a complete check-up, follow the instructions carefully.

Let’s go through the steps now-

Step 1: Check the Resistance Value

First, disconnect all power connections and amplifiers from the drive. Keep the cable of the motor connected to it. 

Take your multimeter and set it to the Ohms test mode. Connect the two testing probes to their particular jacks. Connect the black one to the  “Com” and the red one to the “Ohms” jack. Adjust the multimeter needle to zero.

Now, take the reading of the three wires using the probes. Mark the wires A, B, and C respectively. The testing phases should be in the order- AB, BC, CA. 

The readings should show infinite, which means there’s no problem with the motor. But if it shows 0 or reads any continuity that means there are issues in the motor. 

Always remember to keep the leads of your multimeter separated. They should also not be touching any other cables. Or else they don’t work properly. 

It’s always good to have an extra pair of leads for the meter. We have a list of the best multimeter test lead set for you-

Product 1 
Product 2 

The tips of these leads are strong and they don’t break easily.

Step 2: Find Out Open and Shorted Winding Problems

The windings of your brushless motor can be open or be shorted. An open winding means the motor winding is damaged or separated. A shorted winding means failure in the insulation. 

You can find out these issues using a multimeter.

First, check the connections from wire A to B, B to C, and C to A. The range for each of these wires should be from .3 ohms to .8 ohms on average. 

If the reading shows 0, that indicates a short between the phases. If the reading shows 2000 ohms or infinite, that indicates an open winding.

Step 3: Check the Insulation System

Megohm reading is taken to see if the motor is grounded or not. Also, it can tell if the insulation system of the brushless motor is good or not. 

This time just changes the red probe of the multimeter to Megaohm jack.

You need to supply 1000 rpm of incoming power to your motor. To do this you need to connect your motor with a  good quality bigger brushless motor.

After supplying the power to the motor,  check all three wires in the similar way you did before. The reading will show the numbers between 600-2000 Megohms. The shorts have to be less than 20 Megohms. 

Now, here’s a rule of thumb, if the reading is less than 600 Megaohms, it can indicate damage to the cable.

Step 4: Check the Amperage

By checking the amperage, you’ll know the flow of current in your brushless motor. 

First, insert your multimeter red probe in the “amp’ Jack. Line in the multimeter with the motor circuit. Put the probe in the power wire. 

The amperage reading should be 0. If the reading keeps changing, it indicates a severe issue in your brushless motor.

To avoid these internal issues, regularly check if any part of the brushless motor is failing.

And you are done with testing your brushless motor. Now you know how handy a multimeter can become sometimes. 


Question: What is the advantage of brushless motors?

Answer: Brushless motors are highly efficient and low in maintenance. They produce more torque and work better than brushed motors.

Question: How long is the operating life of a brushless motor?

Answer: A brushless motor can run for 10,000 without any interruption. As they have no brushes, there’s no fear of anything wearing out.

Question: Where can we use brushless motors?

Answer: Brushless motors are being used in industries, cars even in airplanes. Wherever you need high performance and low maintenance, brushless motors are the best options.

Final Words

Hopefully, you understood how to test brushless motor with multimeter. Now you’ll be able to check the motor by yourself.

Don’t forget to share your experience with us.

Take care and have a great day!

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