Location - PAN India Level. Single-phase rotor test. Polarization index test. No Power Outgoing Test: This test is similar to the test above, but tests the outgoing voltage. For a 230/400V system, the expected voltage should be 400V between each of the three-phase supply lines. Motor Casing / Housing. Hence, the input power at zero voltage and no-load is given by OA and it represents the friction and windage loss. Editors and Affiliations. How to test a squirrel cage motor kit. Flowing air cools the motor and reduces the risk of overheating. This is a highly important test to perform, as a motor's turn-to-turn insulation dictates motor reliability. What is No Load Test of an Induction Motor and Block Rotor Test of Electric Motors?
Rotor shafts are usually manufactured from stainless steel, as it is durable, mechanically strong, and has good corrosion and erosion resistance properties. And the reduced voltage is supplied to the motor. All our Rotor Quality Analyzer´s are supplied with our RQA-Win Software for Windows®.
Chosen bolts should have suitable tensile strength and corrosion resistance characteristics. Single phase induction motor designs include: - Split phase induction motors - used in machines where the starting frequency is limited and where the drive does not exceed 1 kW. Squirrel cage induction motor mechanical failure. Field testing & inspection of 3-phase squirrel cage motors - Resource Library. When the sensors are connected, take the ampere reading and turn off the motor. Bad cables or connections – broken or damaged, corroded or loose connections. Before testing, it is important to check the amperage draw your motor requires — this will usually be on the nameplate. Types of Inductors and Cores. A larger surface area allows heat to be removed more quickly by the forced air flow from the fan. The velocity probe or accelerometer is used for measurement.
The electromagnetic fault of squirrel cage induction motor is more complicated and various, mainly including: -. The fins of the motor frame serve as heat exchangers and have a large contact surface area, this increases the heat transfer rate from the motor to the air and thus increases the motor's self-cooling capacity. We also provide a 10 percent repair price guarantee. Pconstant = P 1 + P 2. Short circuit fault. The meter now reads positive, but it is to be recorded as negative. It is estimated that around 70% of machines used in industry today are driven by three-phase induction motors. Nuts and bolts are used for securing parts of the motor together. The procedure determines the running time and temperature reading intervals. Three-phase supply of variable voltage is given to the stator winding. How to test a squirrel cage motor design. Be careful to make sure that the power is actually turned off — on some motors, the disconnect switch is the same as the on/off switch, so switching the disconnect switch to the on position will power the motor. The amount of power may also vary.
Vibration analysts can take data as the rotor spins and split the vibration frequency up into its component frequencies (via Fast Fourier Transform analysis) to highlight evidence of cracked rotor bars. While induction motors exist in numerous forms, this article focuses on the 3-phase squirrel cage induction motor design because it is by far the most common type of induction motor. Construction of a squirrel cage motor. The Induction motor testing(Routine Testing or FAT Test) is performed after completion of assembly by the manufacturer to prove that the motor has the same specification as required in the purchase order. Complete statistics package to facilitate a complete and thorough analysis of both rotor quality and productions capability. Three-Phase Induction Motor – Construction, Working, Types & Applications. Electric motors are highly integrated machines that can develop faults in many areas and, if left unattended, a damaged motor can result in dangerous working conditions.
Download preview PDF. All variable such as current, voltage, power, stator temperature, bearing temperature are measured at the start and also in each 30min based on the test procedure. Experience (1to 3 years)(3-male candidates required). The readings of the voltmeter, ammeter, wattmeters and spring balance are noted down. This can be tested using the following methods: - No Power Incoming Test: To test the incoming voltage, place the multimeter probes on different permutations of the L terminals while the box is powered down. Phase loss operation. But in the case of a large motor, it is inconvenient to apply a large load in the laboratory. Testing of Induction Motor - Methods of regular testing. At this stage, note down the record of the voltmeter, ammeter, and wattmeter. 5 ohms, however, this indicates that the motor's insulation is failing and has the potential to cause an electric shock. Note that there are many methods for diagnosing issues within a motor, and the ones presented in this article are only the most common tests used. Much like a multimeter, a megger has two leads where one connects to ground and the other to specific motor leads. Types of Testing For 3-Phase Motors.
The detection method is to use a multimeter resistance or bridge to detect the DC organization of each phase winding, if it is lower than the specified value, open the end cover to check the winding to find out the fault point, if the damage is not serious available insulation material to repair; if the serious short circuit, has burned the coil, according to the actual situation re-embedding wire processing. Single-phase power supplies one phase at 120 volts, while dual-phase or split-phase power consists of two alternating currents supplied by two wires. Note this test can be very dangerous as it uses an open-ended transformer design, so having skilled technicians is imperative. When you choose Global, you choose high-quality customer service and 24/7 support. And find the intersecting point with the vertical axis. The two primary assemblies within an induction motor are the stator and rotor; the stator and rotor are however built from smaller individual components. Basics of Motor (and Rotor) Testing. Since there are many ways in which a motor can fail, there are at least as many (if not more) ways to test a motor's integrity. Hence, for this type of motor, the no-load test is convenient to determine performance parameters. AIM: To conduct load test on the given 3-φ squirrel cage induction motor and plot the performance.
Polarity Test of a Transformer – Circuit Diagram and Working. A sealed ball bearing allows the rotor to rotate without transferring the rotary motion to other stationary parts i. the motor housing. Induction Motors - What's the Difference? These tools and methods are discussed below. If you're not quite sure what to do or where the problem is coming from, however, it may be worthwhile to call in an electronics repair service to help assess the motor. Rotating electrical machines Part 2: Methods for determining losses and efficiency of rotating electrical machinery from tests (excluding machines for traction vehicles). The c-clip is installed with c-clip pliers. From no-load test (IEC 34-2); from draft IEC 2G/102/CDV; from presented in this paper method. There are two main types of induction motor: single phase (1~) and three-phase (3~).
The voltage between phases, current per phase and absorbed power shall be measured at each data point. When a motor fails to start, runs hot, continually trips or sputters, there are many possible causes. The rotor is also a cylindrical structure with slots on the outer periphery. Compare this with the specifications as noted on the nameplate. Direct Online Starter – DOL Starter Wiring Diagram for Motors. 5) one of the wattmeters read negative, in such cases, the supply is switched off and the connections to the M and L terminals of the wattmeter are interchanged. These resistance measurements must be compensated for temperature after each test; this way, the resistance measurements are standardized when compared over time. Load Test on Squirrel Cage Induction Motor. This device uses a DC voltage (100-5000+ V) to detect insulation breakdown inside of a motor.
It is still used in small devices and those that require low starting torque e. record players, projector fans, photocopying machine fans, hair dryers etc. Mechanical motor testing often includes evaluating a motor's rotor for cracks and shorted laminations. Feed forward neural network. Services are available that will do this testing for you, providing a professional evaluation with none of the hassles of testing your motor on your own.
These values are used for the calculation of temperature rise. This test is done to make sure the continuity and homogeneity of each temperature sensor defined at 100 Ohms for 0°C. Take a reading for the L1 to L2 connection, the L1 to L3 connection and the L2 to L3 connection. A previously-broken motor will never run at the same efficiency, even if repaired, so testing can make sure that the motor retains its performance over the maximum value of its useful life. As the supplied voltage is zero, the stator copper loss and core loss become zero. Understanding Motors.