Course "EEM 41 Three-phase asynchronous machines" Photo: ABB Group SH5007-1D Version 1.0 Author: M.Germeroth Lucas-Nülle GmbH · Siemensstraße 2 · D-50170 Kerpen (Sindorf) Tel.: +49 2273 567-0 www.lucas -nuelle.de Copyright © 2006 LUCAS-NÜLLE GmbH. All rights reserved. LUCAS-NÜLLE Lehr- und Messgeräte GmbH Siemensstraße 2 D-50170 Kerpen EEM41 Three-phase asynchronous machines Training objectives 1 Equipment: 300 W Industrial Series 2 Safety 3 Asynchronous motor 5 Connection and starting 7 Rotation reversal 17 Load characteristics 23 Reactive compensation 31 Asynchronous motor, Steinmetz circuit 43 Connection and starting 45 Load characteristics 51 Copyright 57 EEM41 Three-phase asynchronous machines EEM41 Three-phase asynchronous machines Training objectives This course is designed to convey practical know-how on the topic of three-phase asynchronous machines. Experiment-based investigations of the asynchronous motor are the focus and cover the functioning of the machine, its response and how it operates. Training contents z Motor operation z Nominal data, rating plate z Star cnnection, delta connnection z Star/delta switches z Steinmetz circuit (300W series) z Reactive power compensation z Measurement of phase-to-phase and line-to-line values z Reversal of rotation z Measurement of power output with and without oad Prerequisites z Basic knowledge of electrical machines z Basic knowledge of electrical engineering z Knowledge of using measuring instruments Welcome to the Three-phase Asynchronous Machine course. The team from LUCAS-NÜLLE wishes you lots of fun and success while working through the course topics and performing the experiments. The following pages provide you with an overview of the course content and the required materials. 1 EEM41 Three-phase asynchronous machines Equipment: 300 W Industrial Series SO3636-6U Active machine test stand 300 W 1 each SE2662-2A Coupling sleeve 300 W 1 each SE2662-7B Coupling guard 300 W 1 each SE2672-3G Three-phase motor with squirrel-cage rotor 300 W 1 each SO3212-1W On/off switch 4-pole 1 each SO3212-2D Star-delta switch 1 each SO3212-5U Power supply for electrical machines 1 each SO5127-1Z Analog/digital multimeter, power meter and power factor meter 1 each SO3212-6E Compensation unit 1 each SO5148-1F Set of safety connecting leads 4 mm (47 each) 1 each SO5126-9X Set of safety connection plugs 19/4 mm (15 each) 15 x SO5126-9Z Set of safety connection plugs 19/4 mm with tap (5 each) 5 x 2 EEM41 Three-phase asynchronous machines Safety Basic safety instructions In all experiments using mains voltages high, life-threatening voltages arise. For that reason use only safety measurement leads and make sure that there are no short- circuits. It is imperative that all of the devices, which are provided with an earth or where earthing is possible, must be earthed. This is particularly the case for the frequency converter being used. Always be very careful to check the wiring of the application modules and only switch on the mains voltage after a check has been completed. Whenever possible use a robust current monitoring instrument in the circuit. Always use shaft-end guards and coupling guards as protection against contact with rotating motor parts All locally applicable stipulations and standards governing how electrical equipment is handled must be complied with. 3 EEM41 Three-phase asynchronous machines Safety General instructions on handling the equipment { Check that the knurled screws at the base of the motor and the coupling sleeves (power grip) on the motor shaft are all securely fastened. { Use shaft and coupling guards. { Any prolonged running of the machines when operating under high loads can subject the machines to excessive heating. { The extreme case of the machine being prevented from rotating entirely may only arise briefly. { All of the machines are equipped with a thermal circuit-breaker, which triggers when the maximum permissible operating temperature is exceeded. These switching contacts are accessible on the terminal board and must always be connected to the corresponding connection sockets of the mains supply and control unit. { All measurements have been recorded using conventional measuring instruments (primarily class 1.5) at the standard mains voltage (230/400V +5% -10% 50Hz) using standard production machines. Experience suggests that measurements will lie within the tolerance range of +/-15% with respect to the specified measurement. For more information on this please refer to VDE0530. 4 EEM41 Three-phase asynchronous machines Asynchronous motor Asynchronous motors z Connection and starting z Rotation reversal z Load characteristics z Dynamic load experiments (Classic series only ) z Reactive power compensation On the subsequent pages you will be performing the following exercises on the "asynchronous motor": 5 EEM41 Three-phase asynchronous machines Asynchronous motor 6 [...]... can be found in the appropriate online documentation 23 EEM41 Three-phase asynchronous machines Asynchronous motor Circuit diagram "Load characteristics" (star-delta switch) 24 EEM41 Three-phase asynchronous machines Asynchronous motor Set-up "Load characteristics" (star-delta switch) Recording the motor' s load characteristics with the aid of the "ActiveDrive/ ActiveASMA" software Required settings:... The motor rotates clockwise j k l m n The motor rotates anti-clockwise j k l m n 19 EEM41 Three-phase asynchronous machines Asynchronous motor Switch the motor off and modify the circuit according to the following circuit diagram Turn the motor back on and observe its response again Circuit diagram "Rotation Reversal" (star-delta switch) 20 EEM41 Three-phase asynchronous machines Asynchronous motor. .. when starting the "ActiveASMA" software you will be prompted to select "Application mode") 25 EEM41 Three-phase asynchronous machines Asynchronous motor Experiment procedure: Start the "ActiveDrive/ActiveASMA" software Select the operating mode "automatic speed control" Apply the brake to the motor in 20 discrete steps until the motor ceases to turn ( Note: in the "ActiveDrive / ActiveASMA" software... "Settings" -> "Presets" -> "Machine") In the second graph: Mechanical power P2(n) Power factor cosφ(n) Efficiency η(n) After completing the measurement, export the plotted graph and copy it in place of the placeholder below Determine the the highest possible efficiency η(n) for each operating mode based on the second graph 26 EEM41 Three-phase asynchronous machines Asynchronous motor Placeholder for the load... M(n); s(n) Placeholder for load graph (star connection); P2(n); cosφ(n) ;η(n) (η => "eta") 27 EEM41 Three-phase asynchronous machines Asynchronous motor Placeholder for load graph (delta connection); M(n); s(n) Placeholder for load graph (delta connection); P2(n);cos φ(n); η(n) (η => "eta") 28 EEM41 Three-phase asynchronous machines Asynchronous motor What is the efficiency of the asynchronous machine in... machine at nominal speed in star configuration? MN = Nm What is the efficiency of the asynchronous machine in delta configuration at nominal speed? η = % What is the torque of the asynchronous machine at nominal speed in delta configuration? MN = Nm 29 EEM41 Three-phase asynchronous machines Asynchronous motor 30 EEM41 Three-phase asynchronous machines Asynchronous motor Training content: "Reactive... Asynchronous motor Training contents: "Load characteristics" Record the load characteristics of the motor Determine the nominal torque Determine the highest degree of efficiency Study how the motor responds to loads Assembly instructions: "Load characteristics" Assemble the circuits as specified in the following circuit diagram and set-up instructions Switch the brake on too This does not yet subject the motor. .. EEM41 Three-phase asynchronous machines Asynchronous motor Set-up "Connection & starting" (star configuration) Putting the asynchronous motor into operation in star configuration Required settings: Brake mode: "Torque Control" 9 EEM41 Three-phase asynchronous machines Asynchronous motor Experiment procedure: Put the motor into operation and observe its response Brake the motor down to its nominal speed... Three-phase asynchronous machines Asynchronous motor Set-up "Connection and starting" (star and delta switch) Putting the asynchronous motor into operation with a star/delta switch and recording the load characteristics Required setting: Brake mode: "Torque mode" Experiment procedure: One load characteristic each is to be recorded for the star and delta circuits Subject the motor to the load torques... The star/delta switch has practically no significance at all The star/delta switch permits the motor to start "more smoothly" In practice asynchronous motors are operated only in star configuration EEM41 Three-phase asynchronous machines Asynchronous motor Training content: "Rotation reversal" Identify the difference between clockwise and anti-clockwise rotation Put the motor into operation in both . asynchronous machines Equipment: 300 W Industrial Series SO3636-6U Active machine test stand 300 W 1 each SE2662-2A Coupling sleeve 300 W 1 each SE2662-7B Coupling guard 300 W 1 each SE2672-3G Three-phase. SE2672-3G Three-phase motor with squirrel-cage rotor 300 W 1 each SO3212-1W On/off switch 4-pole 1 each SO3212-2D Star-delta switch 1 each SO3212-5U Power supply for electrical machines 1 each SO5127-1Z Analog/digital. power factor meter 1 each SO3212-6E Compensation unit 1 each SO5148-1F Set of safety connecting leads 4 mm (47 each) 1 each SO5126-9X Set of safety connection plugs 19/4 mm (15 each) 15