![]() Several of our test stands come with automatic, pre-written scripts for calculating the number of poles in your motor, including the Series 1585. Perhaps the simplest way to measure the number of poles in your motor is to have a test stand determine it for you. Measure the speed and frequency simultaneously, then input the values into the equation above to determine the number of poles in your motor. You will also need a device to measure the frequency of the back EMF generated, such as an oscilloscope. To measure your motor speed, you will need a piece of equipment to back-drive your motor (a drill, for example), plus a rotation speed-measuring device to measure the number of rotations, such as a tachometer. This method is most feasible for outrunner motors where the magnets are outside the stator near the surface.īe careful if you attempt this technique as the magnets inside your rotor can be demagnetized by the influence of a stronger magnet.Īnother option that requires a bit more effort and equipment involves finding the motor speed and power supply frequency experimentally, then rearranging the equation below to solve for the # of motor poles: Other simple procedures have been suggested, like waving a magnet around your rotor to see where attraction and repulsion occurs. The relationship is explained by the following formula:įigure 2: Counting the magnets / poles inside a brushless motor The speed of the motor is inversely related to the number of poles in the rotor. Relationship Between Motor Poles and Motor Electrical Speed 8 pole motor → 4 north magnets and 4 south magnets → 4 pole pairs.2 pole motor → 1 north magnet and 1 south magnet → 1 pole pair.For this same reason, you will almost always have an even pole number (2, 4, 6, 8, etc.), as each magnet needs an opposite pole. There are an equal number of north and south magnets facing out from the rotor, and each set of N and S magnets is referred to as a ‘pole pair’.įor each pole pair in the motor there are two poles, so if the motor has 8 poles / magnets, there are 4 pole pairs. The magnets lining the rotor each have their own north and south end, with just one of those ends facing and interacting with the stator. The green stator holds the electromagnetic coils.įigure 1: Motor magnets / poles in inrunner and outrunner motors Motor Poles vs. ![]() In the diagram below, the blue rotor contains the permanent magnets in an inrunner motor (left) and an outrunner motor (right). When an electric current is delivered to the coils in the stator, the rotor starts to turn as its magnets repel the like electromagnets. These magnets are also referred to as the ‘poles’ of the motor. Within a brushless motor, there are a number of magnets lining the circumference of the rotor (figure 1). Part 1: How to Determine the Number of Poles in a Brushless Motor What are Motor Poles? ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |