Newtons4th PPA45 Series Скачать руководство пользователя страница 40

Страница: 40 / 127

PPA45xx Quick User Guide

Page 39

Zoom +

Press Zoom+ to display the 4
selected zoomed measurements as
shown

Note: These will be displayed in the
order they were selected

Pressing Zoom+ again will display only
the

first

selected

zoomed

measurements as shown

Press ZOOM- button to revert real time display back to all measurement
parameters

Содержание PPA45 Series

Страница 1: ...hts are reserved No part may be copied or reproduced in any form without prior written consent Document Title PPA45xx Start Up Guide v4 0 Document Release Date 02nd March 2021 PPA45xx Firmware version...

Страница 2: ...Brightness Page 31 5 5 Adjusting Keyboard Beep Page 31 5 6 Setting User Data Page 32 6 Quick User Guide Page 33 6 1 Wiring Pages 33 36 6 2 Start Up Page 37 6 3 6 3 1 6 4 6 4 1 Zoom Functions Analogue...

Страница 3: ...rnal Datalogs to USB Memory Stick Data Logging to USB Memory Stick Program Store Recall Delete Pages 94 96 Pages 97 98 Pages 99 96 Pages 97 104 8 8 1 9 10 Repair Recalibration Basic Functionality Chec...

Страница 4: ...ice or local sales distributor should any items found to be missing or damaged during transportation Please retain the original packaging to ensure easy and safe return of the equipment for calibratio...

Страница 5: ...d below the line of sight The design also allows storage under the unit without obstruction of the rubber feet so that instruments can be stacked and is easily removed to allow the connection of rack...

Страница 6: ...front of the instrument Pic 3 Also a correctly fitted handle will allow storage under the unit Pic 4 Incorrect 1 Incorrect 2 Fitting the handle from the bottom of the unit as shown here is wrong Inco...

Страница 7: ...1kV rms or dc cat II 600V rms or dc cat III Do not exceed the rated input Keep the ventilation holes on the underneath and rear free from obstruction There are no user serviceable parts inside the in...

Страница 8: ...power cord or cables Doing so may cause an electric shock or a fire Do not place any object on this instrument Do not use this instrument if faulty If you suspect the instrument to be faulty contact...

Страница 9: ...button then the Left Arrow If the problem cannot be resolved directly then you will be given an RMA number and asked to return the unit The instrument will be repaired or replaced at the sole discret...

Страница 10: ...y Screen 2 Screen Display Function Buttons 3 Power Analyzer Mode Buttons 4 Handle 5 Measurement Control Function Keys 6 Rubber Feet 7 Menu Selection and Cursor Controls 8 Measurement Settings Buttons...

Страница 11: ...al channel displays the synthesized phase 3 current The advantage of this connection method is that 3 phase power can be measured with only 2 wattmeters 3 Phase 3 Wattmeter With the 3 phase 3 wattmete...

Страница 12: ...per second Fast Update rate 1 20s Results window size will update 20 times per second Very Fast Update rate 1 80s Results window size will update 80 times per second Window The window application wil...

Страница 13: ...y from the input voltage Current Select Current to detect frequency from the input current Speed Input Select speed input to frequency detection to set frequency via speed input BNC AC line Select ac...

Страница 14: ...e DFT analysis is a compromise between noise rejection of frequencies close to the frequency of the fundamental component and the required stability of the frequency component Normal Default settings...

Страница 15: ...ds less than 100ms Disabled Disable high speed function Enabled Activate high speed data log function COUPLING Coupling There are three coupling options AC only AC DC or DC only AC DC coupling is the...

Страница 16: ...annels onto a higher range than is necessary for the measurement Selecting low bandwidth puts a hardware filter in the analogue input path to eliminate unwanted high frequency components dc dc 5Hz The...

Страница 17: ...r the bandwidth of the processed signal Off Select to switch this mode off On Select to switch this mode on The following screenshots are taken from the Scope display with the PPA set in PWM applicati...

Страница 18: ...n and hold on this range Once this value has been found another test can be carried out by pressing the Trigger button which will restart from the minimum value set parameter use for Low Frequency mea...

Страница 19: ...ich will restart from the minimum value set parameter Manual Selecting this option will allow the user to set up the minimum range from the configured measurements available Minimum Range Pre set curr...

Страница 20: ...igital filter and will not affect the bandwidth of the instrument it is only used for frequency detection The best filter to use for a given application should be selected by experiment The filter doe...

Страница 21: ...g Selectable tracking speed from drop down menu Efficiency Not applicable to the PPA4510 Efficiency can be measured between selected channels from the drop down menu Inrush Current Inrush current surg...

Страница 22: ...r current for a single cycle to charge a reservoir capacitor This pattern is repeated on an irregular basis Most of the power consumed by devices in this mode is taken in the periodic higher current c...

Страница 23: ...d No alarm Linear Frequency of beep increases linearly as value reaches its limit Alarm if high Alarm will sound if values exceed a threshold Alarm if low Alarm will sound if values fall below a thres...

Страница 24: ...sponds to future commands via Comms interface Normal Data Resolution set to 5 decimal points High Data Resolution set to 6 decimal points Binary Data transmitted in Binary Format Interface Communicati...

Страница 25: ...nts front panel Useful for testing inrush current of ballasts ADI40 4 Analogue I O Enable the ADI40 Analogue Digital Interface unit with 4 thermocouple inputs ADI40 8 Analogue I O Enable the ADI40 Ana...

Страница 26: ...ion keys POWER INTEG etc Disabled Function will be disabled Enabled Function will be enabled Zoom 2 High Resolution The data displayed in zoom 2 may be displayed to one digit greater resolution than n...

Страница 27: ...mal to use a phase meter to compare voltages directly The phase meter measures the phase and gain of channel 2 relative to channel 1 using a Discrete Fourier Transform DFT algorithm at the fundamental...

Страница 28: ...ata within location Execute Press to execute any change made to any parameter within PROG mode Memory Status Status of memory in either Internal or USB configuration ZOOM Increase font size on selecte...

Страница 29: ...y stick STOP Stop button will stop any Datalog ZERO Zero button will reset the inputs to zero TRIGGER Trigger returns display screen back to real time from a hold command Also triggers a single shot i...

Страница 30: ...er Guide Page 29 Rear Panel Layout 1 Voltage Current External Analogue Inputs 2 Voltage Current Internal Inputs 3 Mains Supply Inlet 4 Communication Ports 5 Auxiliary Ports 6 Master Slave Connection P...

Страница 31: ...TTING THE TIME Power Analyzer Default Screen Appears Press SYS Key System Option Screen Opens Press Key Flashing Red Cursor will surround Hrs Use Numerical Keys Set Hours within cursor Press Enter Key...

Страница 32: ...ered Press Enter Key Month will be set Press Key Flashing Red Cursor moves to Year Use Numerical Keys Set Year within Cursor Press Enter Key Date will now be Set 5 4 ADJUSTING THE BRIGHTNESS Press Key...

Страница 33: ...sable option Press Enter Key Supervisor access selected Press Key Red cursor moves to User Data Use Numerical Keys On this line we can enter a Company Name Press Enter Key Company Name now set Press K...

Страница 34: ...ed in real time by a high speed DSP digital signal processor A separate CPU central processing unit takes the DSP results for display and communications At the heart of the system is an FPGA field pro...

Страница 35: ...utral configuration L O A D ACH1 VCH1 HI LO HI LO L O A D ACH2 VCH2 HI LO HI LO L L L L N L O A D Three Phase Source or or ACH1 ACH2 Three Phase Load or or VCH1 VCH2 HI LO LO HI HI HI LO LO Ph1 Ph2 Ph...

Страница 36: ...ions Type A and Type B In both cases the Delta voltage is derived from the directly measured phase voltages The difference is that Type B then uses the derived Delta value to back calculate the RMS ph...

Страница 37: ...ss Power Analyzer mode either through the Mode or the POWER button as per the screenshot below Press 8 times until red box surrounds conversion Press to open up dropdown menu selections Press until re...

Страница 38: ...e is pre configured to display relevant parameters Up to 4 functions can be selected and zoomed in These can be viewed within 3 zoom screens the Zoom function is described in the next section of this...

Страница 39: ...ill flash around currently selected zoom parameters Press DELETE Red Boxes will disappear replaced by 1 white flashing box Press Keys Move Box to desired measurement parameter to be zoomed Press ENTER...

Страница 40: ...elected zoomed measurements as shown Note These will be displayed in the order they were selected Pressing Zoom again will display only the first 3 selected zoomed measurements as shown Press ZOOM but...

Страница 41: ...V Peak 50Hz signal will be monitored by the Power Analyzer The frequency will be adjustable by 2Hz Therefore in the above formula Zero will be 50 and Full Scale will be 52 With a Full scale value of 2...

Страница 42: ...5xx Quick User Guide Page 41 Press the SYS button and enable Independent Ranging Press the COUPLING button and set Phase 2 coupling to DC Press the ALARM button and set the Analog output option to ZOO...

Страница 43: ...the Analogue Output settings Enter a value of 50 for Analogue Zero Enter a value of 52 for Analogue Full Scale Press the HOME ESC button to return to the Power Analyzer display Press the ENTER NEXT bu...

Страница 44: ...of the PPA Phase 3 is not used Example 1 The Input signal frequency was set to 50 5Hz The frequency displayed on the PPA was 50 512Hz Analogue Output 10V x measured zero full scale zero Analogue Outpu...

Страница 45: ...of results are from a Datalog conducted with NO smoothing selected thus the data update will be dictated by the speed parameter only Speed set to medium 3 updates per second 50Hz input signal 50 cycle...

Страница 46: ...a single pole low pass filter with an RC time constant relative to the selection mode dependent upon the speed selected We have selected SLOW smoothing with a medium speed giving us a sliding window...

Страница 47: ...ndow during the step between the two peak voltage values Note each speed parameter has its own time constant for smoothing and data updates as shown in the table below Speed Update Rate speed only Nor...

Страница 48: ...ode Access the Power Analyzer home screen and press POWER this will take you into a sub menu Scroll down to the efficiency parameter and press this will open up all available configurations as shown U...

Страница 49: ...f screenshots and instructions To select your measurement application you will need to activate the APP button Use the down arrow to select mode function then press the right arrow to open up the drop...

Страница 50: ...frequency lock and filters will allow the correct measurements to be displayed on such a complex waveform Test device 1 x Inverter Motor test unit set at 65Hz Leaving the PPA45xx in normal app mode t...

Страница 51: ...When default settings have been activated it will allow 5 further parameters to be configured as shown Frequency filter Selectable filter from drop down menu Select a frequency whose range is between...

Страница 52: ...down box will open with all available frequency ranges Press arrows to select frequency filter parameter required Press ENTER to confirm selection By applying a 250Hz filter within PWM mode we can no...

Страница 53: ...4 9Hz Fundamental Frequency Frequency reference Select from the drop down menu which waveform the fundamental frequency is to be synchronised with Voltage or Current Low Frequency Set this parameter t...

Страница 54: ...be derived set conversion to phase to phase rms If however the neutral point is not available then the measurement of the voltage rms is more difficult The options are to use a synthesised neutral or...

Страница 55: ...ynthesised neutral has no effect Consider the delta wired configuration In this case the phase to phase voltages are measured directly and the phase to neutral values are derived set conversion to del...

Страница 56: ...Speed BNC connectors on the rear of the instrument Open up the torque and speed drop down box to select which type of test is to be configured Once a configuration has been selected you will be requir...

Страница 57: ...ALLAST MODE Select Lighting Ballast mode from the Application Menu as in previous applications Press to default settings Press ENTER to load Once selected you now have the option to select the frequen...

Страница 58: ...samples and analyses every sample at the full sample rate in excess of 2Msamples s to catch even very fast peaks Set Up Instrument Used PPA4530 Std 30Arms Test Device 230v 50Hz Ventilation Fan Imax 0...

Страница 59: ...e current settings as follows Set the autoranging parameter to range up only and the minimum range to the 30mA range this will allow the test being carried out to find the highest range via peak detec...

Страница 60: ...by cycle measurements on the input signal then set the frequency lock to Dynamic Setting Peak Measurement Parameters If required you can display the Peak and Peak measurements within the RMS Voltmeter...

Страница 61: ...gging to Internal Memory Set the Datalog to be performed to the internal RAM memory this will offer the user the fastest performance Set the interval time to 0 00s to enable the Datalog to capture eve...

Страница 62: ...display all the data points taken from the associated DataLog and you will notice that the Inrush Current Surge is displayed as being 2 742A Pressing the GRAPH button will display in a graphical forma...

Страница 63: ...Mode using the N4L PCIS Switch For the worst case inrush current the input to the device under test must be switched on at the worst point in the cycle 90 or 270 for a capacitive load 0 or 180 for an...

Страница 64: ...45 Press Drop down box will open with all available angular ranges Press arrows to select angular parameter required Press ENTER to confirm selection Switch on Cycles Press Key Switch on Cycles param...

Страница 65: ...dow Test device 1 x Single Phase Transformer ratio 1 1 Accessories 1 x Break out Box Transformer Mode will allow the user to assess and view characteristics applicable to the transformer field under t...

Страница 66: ...u require For this manual single phase 1 was selected to reflect the transformer being used Press ENTER to confirm selection then HOME twice to return to the power analyzer home screen The Power Analy...

Страница 67: ...r values displayed within the Orange Box see previous page are computed in transformer mode In transformer mode there is usually very little distortion The equations used to calculate these values are...

Страница 68: ...the Impedance Meter screen Press IMP button again to enter Measurement Settings screen Press button 2 times red box surrounds parameter settings Press button to open up the drop down menu From the dro...

Страница 69: ...ntuitive manner without the requirement for a vector display this has the advantage of maintaining 5 digit resolution which is not possible whilst attempting to visually interpret phase balance on a c...

Страница 70: ...The calculated values for Pcorr and K factor are displayed for each phase this can be seen in the Orange box below On the SUM screen the displayed Pcorr value is the sum of the Pcorr values for each o...

Страница 71: ...menu selections Press 5 times until red box surrounds standby power Press ENTER this will now set the mode Press to move to default settings and press ENTER The instrument will now set the voltage an...

Страница 72: ...es 1 x Break Out Box The real time display shows a screenshot from the Power Analyzer home screen with the test device in standby mode Reverting to the RMS screen you can see all the subsequent voltag...

Страница 73: ...72 Left is a display taken from the power integrator screen INTEG displaying a 1 minute integration of the power being consumed Press SCOPE button to view the Voltage and Current waveforms being prod...

Страница 74: ...in combination with N4LCal N4L Calibration software which facilitates performing manual calibration with an external source This software is supplied with a detailed manual describing the calibration...

Страница 75: ...any real value between 15 s div to 5s div Pressing the arrows on the main panel will adjust the timebase by a factor of 2 Trigger Reference The data source for the trigger can be selected to be eithe...

Страница 76: ...set to ON a low pass filter is applied to the trigger data to stabilise the trace with noisy signals The filter only influences the trigger detection and does not change the data displayed Pretrigger...

Страница 77: ...above the display shows all fundamental measurements from the position of cursor 1 Also displayed is the time difference between the 2 cursors delta t 26 00ms with the timebase set to 10ms div Trace...

Страница 78: ...PPA45xx Quick User Guide Page 77 Trace set to Voltage Trace set to Current Trace set to Dual Trace set to Together...

Страница 79: ...measured and displayed in an Excel report using PPA Datalogger software Connect the PPA4500 to the PPA Datalogger software Version v3 1b and above can be used but v3 2e is recommended Set up the softw...

Страница 80: ...2 Enter the Harmonics mode and select Computation Interharmonic Sweep Step 3 Frequency Step Enter the required frequency Selected Harmonic Enter the harmonic Harmonic Series Up To Enter the number of...

Страница 81: ...PPA45xx Quick User Guide Page 80 Step 4 Click the Set up PPA button Step 5 Click the Start button...

Страница 82: ...umber of harmonics included in the sweep The software will display a message Waiting for Results Depending on the settings selected a flashing message may be displayed on the PPA Sweep Running For all...

Страница 83: ...PPA45xx Quick User Guide Page 82 Step 7 On completion of the tests the software will start to download the results from the instrument The message is updated once the results have been downloaded...

Страница 84: ...e ACQU button and entered the required speed setting Press the MODE button and select Harmonic Analyzer mode and Interharmonic sweep Enter the required values for Frequency step size Selected harmonic...

Страница 85: ...rter Motor test unit single phase 1 x HF 003 Current Shunt shunt resistance 470m Wiring Configuration Connect BNC safety lead between the A EXT BNC on the rear of the PPA45xx and the BNC connector on...

Страница 86: ...cting the external shunt to a different channel then use the arrow to select the correct channel configurations screen as prompted at the bottom of the RANGE home screen Now going back to the real tim...

Страница 87: ...bracket on the HF500 shunt It is essential that 2 correctly sized spanners are used at all times see table below so that adequate torque can be applied to the bolt without transferring excessive turni...

Страница 88: ...r The shunt value is set to 2m to reflect the switch position being set to 1KA 2mV per A and a scale factor of 1 1 We set 2m as a 2m shunt would also produce the same 2mV A Multiple turns around the c...

Страница 89: ...ide Page 88 WARNING Remember to connect either the Internal or External shunt only to the PPA45xx WR5000 Wideband Rogowski Transducer On Fault OFF 5KA 0 4mv a 1KA 2 0mv a BNC DC Input 15 Way Connector...

Страница 90: ...n the connector nut to secure the lead into position A single coil wrapped around the conductor will result in voltage measurement equal to the 2mV A detail on the WR5000 as set on previous page If th...

Страница 91: ...sted in table 1 The LEM 6 supplies the LEM transducer with a highly stable isolated supply voltage each channel is isolated from the next providing excellent cross channel coupling immunity There are...

Страница 92: ...5000 System Calibration If the LEM 6 is purchased with an N4L power analyzer and LEM transducers the LEM 6 Interface can be system calibrated within N4L s ISO17025 UKAS laboratory This provides the en...

Страница 93: ...led each time the instrument is switched on Should it be preferred to not have them automatically recalled they can instead by saved to an alternative memory location and then deleted from location 1...

Страница 94: ...set the Data Resolution to 5 decimal points plus any exponent e g 1 2345 E00 Selecting High will set the Data Resolution to 6 decimal points plus any exponent e g 1 23456 E00 For higher speed transfe...

Страница 95: ...rate from the 4 options given in the drop down menu Default Setting is 19200 To use a USB lead to connect set the interface parameter to read USB Configuring the interface to LAN will then display the...

Страница 96: ...re set Comms configuration to be recalled if saved along with a nominated program within the PROG settings To recall a Comms configuration set the recall option to ON then recall the appropriate progr...

Страница 97: ...sferring Internal Datalogs to USB memory stick The following section explains the procedure for storing a datalog to internal memory and exporting the data to a USB memory Stick 1 Setup Datalog DATALO...

Страница 98: ...ate file on memory stick the file format will have a txt extension D001 represents location 1 as specified above 6 NOTE Data presented within the txt file for time will be displayed as a fraction of a...

Страница 99: ...uick User Guide Page 98 7 1 1 Data logging to USB memory stick 1 Setup Datalog DATALOG MENU 2 Press START to commence Datalog 3 Press STOP to terminate Datalog results will now be stored upon USB memo...

Страница 100: ...xt file will require the user to download free of charge from the N4L website software application n4ldlog n4ldlog exe 6 Upon downloading the n4ldlog software then drag and drop the N4L file on top of...

Страница 101: ...following section explains the procedure for storing recalling or deleting a program to or from the instruments internal memory or USB memory Stick 1 Press PROG button to open up program store recall...

Страница 102: ...PPA45xx Quick User Guide Page 101 3 Select which data type you require to be actioned from the list shown 4 Select the action to be taken in association with the data selected...

Страница 103: ...ion 0 FACTORY DEFAULT and cannot be changed Location 1 Upon start up should any program be stored within program 1 then the PPA will automatically recall this program 6 Enter a name within this parame...

Страница 104: ...PPA45xx Quick User Guide Page 103 7 Upon implementing any of the above actions then remember to scroll down to EXECUTE and press ENTER to validate your selection action...

Страница 105: ...ibrated annually Contact details 1 Newtons4th Ltd 1 Bede Island Road Leicester LE2 7EA United Kingdom Tel 0116 230 1066 International 44 116 230 1066 Fax 0116 230 1061 International 44 116 230 1061 E...

Страница 106: ...tions Details are provided of the instrument setup the required connections between the PPA and other basic test equipment commonly available in a laboratory Furthermore screen shots of the expected r...

Страница 107: ...o access Program Store Recall mode Press PROG button Press Key until Red Box surrounds the number adjacent to Location Enter 0 Press Key until Red Box surrounds Execute Press ENTER This will now reset...

Страница 108: ...ons Use the buttons to select ac dc from the drop down list Press Key until Red Box surrounds the Bandwidth options Use the buttons to select wide dc 2MHz from the list Ranging Press RANGE button Pres...

Страница 109: ...s the attenuator options Type in an attenuator setting of 1 0000 1 Press Key until Red Box surrounds the Current input options Use the buttons to select external shunt from the list Press Key until Re...

Страница 110: ...rnal current inputs these are 3Vpk Max Isolated Differential Voltage inputs The PPA is connected to the signal as shown in the drawing The various modes on the instrument can then be selected The foll...

Страница 111: ...PPA45xx Quick User Guide Page 110 Connection diagram for the functionality checks of the External BNC inputs...

Страница 112: ...e scope mode display current and voltage for all 3 phase inputs Use the ENTER NEXT button to scroll through the various oscilloscope displays The screenshot below shows current and voltage for phase 1...

Страница 113: ...ase inputs These allow comparisons of current and voltage readings between the 3 phases It is also possible to check that the instrument has detected the correct frequency In this screenshot we are lo...

Страница 114: ...omparison of current power and voltage can be made on all 3 phases and it is also possible to check that the instrument has detected the correct frequency Harmonic Analyzer Mode The signal generator i...

Страница 115: ...form so that it is possible to look at all of the individual harmonics at once This example was for the voltage harmonics but it is also possible to get the same table format for current harmonics We...

Страница 116: ...ernal measurements The only difference is in the configuration of the Ranging settings Ranging should be set up as follows Press RANGE button Press Key until Red Box surrounds the Voltage input option...

Страница 117: ...and current levels are applied to the 3 phase inputs of the PPA Therefore the display should indicate the nominally same values for all 3 phases For the tests in this document a 230V 50Hz mains suppl...

Страница 118: ...PPA45xx Quick User Guide Page 117 Connection diagram for the functionality checks of the Internal 4mm sockets inputs...

Страница 119: ...A Display when making internal measurements The following screenshot examples were taken with the PPA set up for internal measurements For full descriptions for each of the PPA modes please refer to t...

Страница 120: ...PPA45xx Quick User Guide Page 119 True RMS Voltmeter Mode Power Analyzer Mode...

Страница 121: ...erification Verify that Vthd is nominally the same across all phases inputs as a reference signal such as a squared wave is not being used we cannot verify individual harmonic magnitudes This is not a...

Страница 122: ...attenuator caused by excessive voltage Incorrect Current reading on External Input Possible damage to input attenuator caused by excessive voltage Incorrect Voltage reading on Internal Input Possible...

Страница 123: ...k to 3Vpk in 8 ranges Accuracy 0 03 Rdg 0 04 Rng 0 004 x kHz 3 V Current Input Internal Shunts 10A rms Shunt 4mm Safety Connectors Ranges 10mApk to 30Apk 10Arms in 8 ranges Accuracy 0 03 Rdg 0 04 Rng...

Страница 124: ...g 0 08 Rng 60 A SC Current Internal 0 06 Rdg 0 08 Rng 600 A HC Current Internal 0 06 Rdg 0 08 Rng 1 8mA Current External 0 06 Rdg 0 08 Rng 6 V Total Harmonic Distortion THD Accuracy Voltage Normal hi...

Страница 125: ...ange 1Hz to 1MHz Accuracy 0 01 Rdg Datalog Functions Up to 4 measured functions user selectable 30 with optional PC software Datalog window No Gap analysis Minimum window 10ms Memory RAM or non volati...

Страница 126: ...chronization for 4 6 phase mode Extension Master slave control and N4L accessory port Physical Display 320 x 240mm Colour TFT Display White LED Backlit Size 130H x 400W x 315D mm excl feet Weight 5 4k...

Страница 127: ...0 Bandwidth 1MHz 2MHz 2MHz V I Accuracy 0 05 0 1 0 03 0 04 0 01 0 038 W Accuracy 0 1 0 1 0 04 0 05 0 03 0 02 PWM Mode N Y Y Transformer Mode N Y Y Minimum Window Size 2ms 10ms 2ms Scope Y Y Y Harm ord...

Результаты поиска

Содержание PPA45 Series

Отзывы:

Newtons4th PPA45 Series, Руководство для стартапов, Страница: 40 / 127

Результаты поиска

Содержание PPA45 Series

Отзывы: