Custom motor test systems for dc motors, aerospace motors, automotive motors, appliance motors, power tool motors, dentalsurgical motors and pump motors. The three resistance readings of a threephase induction motor are compared and calculated to obtain the resistive imbalance. Dc spindle drive problems are often caused by motor problems. This method will ensure that the separate windings. They provide the most surface contact since they are worn in. No special circuits or hardware are needed to determine the speed of a dc motorinstead, you can use the power supply thats powering the dc motor. Yes, i would like to receive emails from motordoc llc. Electric motor testing is usuallly the first thing to be sacrificed when cutting back on operational expenses. The power that a dc machine receives is called the input and the power it gives out is called the output. Rotate the end shaft approximately 30 degrees and test the motor again.
However, speed varies widely between no load and full load. Perform this procedure a number of times as most dc motors use a carbon brush and copper commutator to conduct the electrical power to the armature. A protocol involving voltage level, time duration, intervals between tests and connection methods must be composed, taking into account the type and size of the equipment, its value and role in the production process and other factors. The smaller the losses, the greater is the efficiency of the machine and viceversa. Dc motor brochure singles tecowestinghouse motor company. Note before removing dc motor brushes always put the brush back in the same hole of the motor.
Fanuc cncs offer the best performance for machine tools in virtually every industry, from mills and lathes to highly complex 5axis applications. What i have done is actually built a test jig to apply actual voltages to both field and armatu,re. Testing and commissioning procedure for electric motors eep. Jul 17, 2017 release the push button on the megger or stop the cranking of the meter. Dc motor fault zone analysis is a vital part of any dc motor maintenance program. To understand insulation testing you really dont need to go into the mathematics of electricity, but one simple equation ohms law can be very helpful in appreciating many aspects. They are similar to dc motors since they have linear characteristics. Dynamic testing of the motor with repeated test cycles and data acquisition of measured parameters torque, speed, input current, input voltage, temperature, inputoutput power, power factor and time components magtrol has developed a customized test system dedicated to the automatic testing of small dc motors ranging from 7 to 75 w. It should be noted that the scope of motor testing depends upon the motor type and size, this being indicated on the inspection forms. The brush face must be shiny and conform to the arc of. Singlephase twophase threephase the presentation will describe the basics of the threephase brushless motor because it is the most common version.
Before you send your drive to be fixed, test your spindle motor. Oct 28, 2015 in direct method of testing the generator or motor is put on full load and whole of the power developed by it is wasted. Presently, very little research has been performed using current signature analysis on dc motors. Dec 30, 2018 the load testing of dc machine is needed to determine the rating of a machine. Dc motors designed for your application dc motor applications. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications.
This article mainly deals with the determination of the efficiency curve. Siemens dc motor test run on dc motors test stand rgb elektronika duration. The basic testing equipment you will need to troubleshoot dc motors in the field includes. A guide to motor compliance standards ohio electric motors. Check out our variable speed brushless dc controls for a drive that is specifically designed to match our motor. En 603351 iec 3351, safety of domestic electrical appliances. In this method, the motor is put on the direct load by means of a belt and pulley arrangement. Information, editorials and tech tips for you to use. Mar 16, 2017 in dc series motors, the swinburnes test cannot be done to find its efficiency as it is a no load test.
Some of the dc motors have integral gearboxes gearmotors and some are attached to a variety of gears, belts, pulleys, etc. However, these tests have not been designed exclusively for motor life testing. But smart companies understands is that what this means for maintenance programs is billions of dollars of lost revenue through increased motor repair costs, downtime, and waste in industrial and commercial companies. Armaturerelated anomalies can include commutator bar defects, riser defects very common and shorted turns or coils in the armature circuit. This paper is a brief introduction to online fault diagnosis of dc motors using current signature analysis.
In a series dc motor the field is connected in series with the armature. Ac motor testing performed with pdma mce offline tester resistive imbalance during this test a dc voltage is applied to the motor. The complete guide to electrical insulation testing. For example, providing pure dc voltage to a pm dc motor will allow for better motor performance than providing full wave rectified fwr vo ltage from an ac source, as shown in fwr vs. Mar 18, 2016 in this post, we are going to test the current sensor board using a typical toy dc motor as the load. This paper is a brief introduction to online fault diagnosis. Thorough testing of every dc motor we build is conducted at our manufacturing plant in round rock. In order to properly control a bldc motor, some theoretical knowledge is necessary. Its operation is based on the principle that when a current carrying conductor is placed in a. Testing the coiled frame 37 testing after repair without armature 37 testing after repair 37 the connection boxes 38 changing the position of the connection box 3839 insulating the terminal connections 39 assembling the connection box 3940 differences for shunt motors 40 the commutator 41. If a machine produces too much heat then it can affect the insulation of the machine and ultimately it can cause the breakdown of the machine. In direct method of testing the generator or motor is put on full load and whole of the power developed by it is wasted. In most cases, the considerations can be extended to the other types.
Visual inspection and electrical testing of the armature and fields give the maintenance personnel an understanding of the condition of the motor. Knowledge gained through prototype development and critical testing has significantly influenced the technology employed, broadened markets and. Each lab station is also equipped with an agilent e3630a triple output, variable. Brake test on dc shunt motor another method of testing the d.
The amount of power is somewhat proportional to the motor load so tests typically automatically ramp the load to form a curve of input electrical power to output mechanical power. Brushless motors overview there are different types of brushless motors. Threephase dualvoltage motor insulation resistance testing threephase dualvoltage motors are used for most daytoday operations in todays industrial plants. Threephase dualvoltage motor insulation resistance testing.
The test generally applies between 100 and 5,000 v or more. We are constantly doing what everyone else just talks about. A dc motor runs from a dc power supply, but the motor currents are typically not very flat due to primarily to the motor commutating when the brush moves to a different coil on the armature. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors.
Efficiency classes of singlespeed, threephase, cageinduction motors iecode under 5. Megohmmeter ac voltmeter dc clampon ammeter ohmmeter dc voltmeter tachometer find out if the failed motor was. Electric motor testing explained the electricity forum. In dc series motors, the swinburnes test cannot be done to find its efficiency as it is a no load test. A characteristic of series motors is the motor develops a large amount of starting torque. But for compliance testing, the ul thermal tests are the primary interest. The direct tests can be used only on small machines. Motors are susceptible to the gradual failure of their insulation resistance. Typical inspections when troubleshooting dc motor problems or doing preventative maintenance. A complete retrofit upgrades cnc components, motion control equipment, and motors and drives. During the manufacturing process, electric motors endure a variety of tests to ensure proper operation and integrity. This test can be done in your own workshop using simple hand tools and a specialized electric testing device.
In this post, we are going to test the current sensor board using a typical toy dc motor as the load. The open circuit test gives the mmf and hence the excitation current or field current needed to generate the required voltage on no load at a fixed speed. The result is a high standard of quality control that reinforces our manufacturing excellence. Facilities must be available for decoupling the motor from the loading system in seconds. Take care not to use two motors on the same gear set, use the big gears with the little gears in a high torque situation, or to drive the motors under high torque for a long period of time running into a wall, and keeping the wheels moving.
The load testing of dc machine is needed to determine the rating of a machine. Dc motor armature testing iacdriveac drives solution. Fields test for series motor this is one of the methods of testing the d. When we run a machine, then some energy is lost in the machine, which converts into the heat and cause temperature rise. Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. Motordoc llc provides electrical machinery, electrical reliability and industrialcommercial consulting and training as well as the first continuous monitoring electrical and current signature analysis system and esa data collection systems. Speed control is an important factor in these applications. The dc motors are used in many applications like process control and automation in industry, robotics, printers, and scanners also. Assuming the field source in your spindle drive works. Dc motor troubleshooting, inspection and learn to repair of dc motor brushes and commutators. Give a dc voltage across the commutator segments for one pole pitch area from a power supply or battery. The determination of the efficiency of dc machine is important for the testing of dc machines. The issue of sealing elements is also partially dealt with in iec 6003430. Small brushless dc motors use electronic commutation eliminating the need for maintenance.
Testing of dc motor, dc motor testing direct and indirect. The noload test follows the load test immediately, with the motor at essentially the same temperature as at the end of the load test. Our high power density bldc motors are low noise, making them an ideal solution for security and medical applications. From this voltage the actual resistances of the windings are measured. Additionally, the voltage type ac or dc must match the motor type or be converted to something that works with motor type chosen. Adjust dc source until rated current flows formulas for wye connected stator dc for delta connected stator dc dc i v r 2 r r dc 1 r 1 1. Motor vibration shall be measured in a triaxial direction, i.
The open circuit characteristic curve shows the variation of induced emf as a function of field current at constant. Our test facility is one of the most advanced in the world. A starter motor for a big car will take 200a at 10v while it is cranking the engine over. For example, ul 2111 stipulates the following acceptable temperature rises for nema b electric motors. Reliability life testing and evaluation of 3phase motors. They are similar to ac motors in that a moving magnetic field causes rotor movement or rotation. Motordoc llc provides industrial and commercial consulting, training and technology for electrical and mechanical system reliability. Brake adjusting the tension of belt, the load is adjusted to give the various values of currents. Dc motor analysis a leader in electric motor testing. Whilst using meter and megger meters check out the continuty and grounds it cannot really check a dc motor out propelly. Bldc motors are the best choice for rc cars due to their efficiency versus brushed motors and the availability of such motors for rc cars. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Operating successfully for a period of time before failing. You could be reading the correct value depending on what sort of motor you are testing.
Basics of dc motors for electrical engineers beginners. Brushless dc motors were intensively developed and tested over several years before. May 27, 20 speed of dc motor depends upon the average dc voltage applied across its armature. The table below gives the recommended test voltage and minimum insulation resistance values for motors and generators by voltage class. Dc motor armature testing for a dc motor armature, there is a simple method of determining the condition of the armature. Razor scooter wheel motor at first glance, a brushless directcurrent bldc motor might seem more complicated than a permanent magnet brushed dc motor, but the purpose of the following is to emphasize the simple analytical techniques that can be used to understand the operation of a bldc. Dc test finds r 1, the stator conductor resistance procedure. The open circuit test is needed to determine the open circuit characteristic or magnetizing characteristic of a dc machine.
The efficiency of a dc machine depends upon its losses. Bldc motor theory brushless dc motors are synchronous motors that are powered by a switching dc power supply. I have been working with dc motors,drives etc for over thirty years. Speed of dc motor depends upon the average dc voltage applied across its armature. These motors run conveyor belts, pumps, fans, and many other applications. The figure below shows crosssections of ac, dc and brushless dc motors. Basics of dc motors for electrical engineers beginners on photo. Motor nameplate voltage ac or dc test voltage dc minimum insulation resistance up to 250 volts 500 volts dc 50 megohms 250 to 1,000 volts 1,000 volts dc 100 megohms. Geared motors and pump motors are often standard motors equipped with. The field is wound with a few turns of large wire because it must carry the full armature current. If the polarity of the power supply is changed, then the motor runs in reverse direction. Brushless dc motors combine characteristics of both dc and ac motors. These motors are extremely susceptible to burning out when they are over driven.
1532 231 687 1026 1408 1071 68 900 24 316 874 718 1258 678 853 48 861 573 1436 1100 1244 340 1262 95 656 755 1132 1057 1074 1430 966 1434 1321 439 1022 1419