DIGITEK MOTOR CONTROLLER. For Standard 50 Hz AC and Squirrel-cage Motors. Technical Handbook DIGITEK-IIIGS CC For General Purpose

Transcription

1 DIGITEK MOTOR CONTROLLER For Standard 50 Hz AC and Squirrel-cage Motors Technical Handbook DIGITEK-IIIGS CC For General Purpose SOFT START ENERGY SAVING MOTOR PROTECTION Innovative Energy Ideas 1

2 TABLE OF CONTENTS 1. About DIGITEK 2. Soft Start and Soft Stop 3. Energy Saving 4. Features 5. Specifications 6. Models 7. Installation Safety Guideline Notes on Installation Installation Diagrams Basic Installation Diagrams Installation Diagram with Remote Control System Installation Diagram with External Bypass System 8. Setup and Operation LCD Display Choice of Parameters Setup Procedures Operation Procedures Phase Loss Protection Over Current Protection Energy Saving Adjustments 9. Applications Appendices Appendix A: Horse Power, Kilowatt, Rated Voltage and Rated Current of a Motor Appendix B: Hex Numbers VS Decimal Numbers Appendix C: Capacitors and Energy Saving 2

3 1. About DIGITEK Rapid development of industry and luxurious raise of living standard make the energy shortage a worldwide concern. Even worse, much of the energy is wasted. The energy consumed by induction motors is one of the vivid examples that a lot of energy is unnecessary wasted. As early as 1977, it was already pointed out by NASA scientists that an induction motor often consumes more energy than needed. Since its inception, Digitek has focused its resources on developing energy saving devices for induction motors. With our strong multinational research and development team, we began to have our basic energy saving device available in the market. Though, our products had been quickly accepted in the market in a very short time, we understood the need to further develop more specialized products for better applications. Our first successful unit was that for the oil pump jack. With the help of many oil companies worldwide, we had developed a special unit for oil pump jack. This unit is now widely used in many oil fields. Currently we are working on a new oil pump jack energy saving device, DIGITEK-IIIOP, for wider range of application. We had then further developed a unit suitable for single-phase coolers and freezers. This unit was designed by taking into account of the operational features of refrigeration compressors. This unique unit can save energy more than 20%, depending on the design of the coolers and freezers. The application of this unit is rapidly growing. It not only helps saving energy, but also provides many protections for refrigeration compressors. As a result, some of the traditional protection devices are not needed. This design has patents from the United States and many other countries. Many of the well-known companies including many distributors of Coca Cola in many regions have already installed this unit in their coolers, in order to save energy, to enhance their ecology protection image, and to strengthen their market competition power. We have now developed a three-phase motor control device, DIGITEK-IIIGS, with features including soft start, soft stop, energy saving, phase loss protection, low and high voltage protection, over current protection, remote motor start-stop control and external bypass. The patent for this design is under pending in many countries. Based on this sophisticated system, we now have further developed a most efficient energy saving control system, DIGITEK-IIIAC, for three-phase medium size air compressors with air reservoir. When the motor is running with air compressor loaded, DIGITEK-IIIAC saves energy according to the load of the motor. On the 3

4 other hand, when the motor is running with the compressor unloaded, instead of keeping the motor running as in the conventional case, DIGITEK-IIIAC stops the motor completely. The soft start allows a compressor to start and stop frequently. This design has patents from the United States and many other countries. In addition to motor controllers described above, we have developed energy saver specifically for fluorescent and HID lighting system. For power supply at rated voltage, this device can save energy 15 % or more. With this energy saving device, DIGITEK-ILT, the luminosity is kept to that required by lighting system designed. It also prolongs the life span of the lighting devices. This design is under patent pending in many countries. Digitek Technology is a company committed to the development of best energy saving motor control system. We emphasize on energy saving devices for specific applications in order to enhance the energy saving efficiency, the motor protection capability and the power supply stability. We have strong research and development team, efficient production facilities and rapid growing of worldwide marketing network. 2. Soft Start and Soft Stop It is well known that when a motor is started with full voltage the high inrush current can cause serious contamination on the power network. The easiest way to lower the starting current is to lower the starting voltage. Y- motor starter is commonly used in the industry. However, with Y- starter the inrush current can still be as high as 3 to 5 times of the rated current of the motor, and can still cause certain degree of power network contamination. In order to avoid serious effect on the power network, it is very often starting motors not at the same time. By doing so, workers have to wait for the machines to be started in turn. As a result there is waste of working power. Soft starter is an idea device to start a motor. DIGITEK-IIIGS is not only an idea soft starter, but is also a device for energy saving on motor. For some applications such as water pumps soft stop is also very important. For example, soft stop will reduce positive surge pressures in pipelines on shutdown. Other application such as conveyer belt systems where sensitive load such as bottles are being transported also requires soft stop. The following wave graphs are for a 10 hp 220 V motor started with full voltage and with DIGITEK-IIIGS with different soft start setting. 4

5 Full voltage start 115 I 28 0 Rated current Fig. 2.a t Fig. 2.a shows that the highest inrush current is almost as high as 4 times of the rated current. Different motors with different sizes and loads have different inrush currents and an inrush current can be as high as more than 7 times of the rated current. Soft start I Rated current Fig. 2.b t Fig. 2.b is a typical soft start wave graph. Soft start with lower soft start voltage I Rated current Fig. 2.c t 5

6 The soft start voltage for Fig. 2.c is set lower than that for Fig. 2.b, therefore the current is lower, less than twice of the rated current, but with longer time to finish the start. When the starting voltage is too low, it might have difficulty to start a motor. The torque of a motor is proportional to the squire of the voltage and it requires a minimum torque to start a motor. Soft start with soft start time too short I Rated current Fig. 2.d t When the setting of soft start time is too short to complete the motor start, after the soft start time there will be an increase on the current as shown in Fig. 2.d, because after the soft start time the voltage to the motor returns to full voltage and causes the increase of the current. Soft start with soft start voltage too high I Rated current Fig. 2.e t When the soft start voltage is not low enough, one might not get the flat plateu as shown in Fig. 2.b or Fig. 2c. 6

7 Kick start + Soft start I Rated current Fig. 2.f t For a large motor with large starting load, a large voltage at start might be needed to provide a larger torque to overcome the large moment of inertial at start. After the initial kick start, it can then turn into soft start mode. Soft stop Voltage I 5 sec Current Fig. 2.g t I 5 sec t Fig. 2.h 7

8 Fig. 2.g and 2.h are voltage diagram and current diagram respectively with soft stop voltage setting 55 and soft stop time 5 seconds. Soft stop is specified by soft stop voltage and soft stop time. Lower soft stop voltage makes motor stop softer. The voltage drops to the stopping voltage within the stopping time. 3. Energy Saving It is well known that there is an intrinsic limitation on the motor efficiency. There is always some input energy that has not been converted into mechanical output energy. It is also well known that some of this wasted energy can be saved. There have been many suggestions to save the wasted energy before. By making use of a variable voltage transformer (e.g., variac) to reduce the voltage by brut force was once a popular idea. However its application in practice is quite limited and this approach has never become popular in practice. Another approach to save the wasted energy is to limit the energy supply enough for normal operation of the motor. The basic idea is to make use of thyristor to turn off part of the energy supply cycle. This basic idea first developed by NASA more than 20 years ago has been constantly improved ever since. Nevertheless, there is some limitation in the development in the past due to the available electronic technology. In effort to save the wasted energy by a motor, the wasted energy usually means the real power, namely the KW charged by the utility company to the user. The reduction of the wasted real power not only lowers the utility charge to the user, but also prolongs the motor life. The wasted energy increases the temperature, the vibration and the friction of the motor and shortens the life of the motor. As the charge on the demand by utility company becomes more important to the user, saving on the reactive power, KVAR, also becomes more urgent. The Digitek-IIIGS Motor Controller is not only designed for saving the real power, KW, but also for the reactive power, KVAR. There are mainly two ways to save the real power suggested in the past, namely by brut force reduction of voltage with variable voltage transformer (e.g. variac) or by truncating part of the power supply cycle to reduce the power supply. Digitek-IIIGS Motor Controller adopts the approach of truncating power supply cycle. It simply detects the load on the motor and through a micro-controller sends a firing signal to turn on the SCR to a conductive state. The SCR will be turned off automatically when the current through the SCR is zero. The firing angle on the SCR depends on the load and the energy saving characteristics preprogrammed in the micro-controller. 8

9 In the past, there has been emphasis on the measurement of the power factor as load reference and SCR firing angle is then related to the power factor through micro-controller. An apparatus so designed is often referred as power factor controller. In fact the power factor is only used as a load reference. The switching off of SCR helps to reduce the power supply, but it is not necessary to help reducing the real power consumed by the motor. For example, for a three-phase motor, the real power is related to the voltage, current and power factor as follows: KW = 3 V x I x Power Factor (cosθ) Here we see that a lowering of voltage and current can not guarantee the lowering of KW, because there is a possibility of increase of power factor. It is quite misleading to say that KW is reduced because V and I are reduced. The combination of over all change on V, I and PF determines the change on KW. In some cases, an increase of power factor might balances out the reduction of V and I and therefore results in no decrease in KW. An increase in cosθ means a decrease in sinθ and a decrease in sinθ can help to reduce KVAR, the reactive power. Reactive power KVAR, voltage and current are related as follows: KVAR = 3 V x I x sinθ KVAR can be lowered when V and I are lower with sinθ also lower or at least not too much increased. DIGITEK-IIIGS can start a motor with kick start, then turn into soft start. After the completion of soft start, it can turns into full voltage operation during the power on time. Finally at the end of power on time it turns into saving mode. Fig. 3.a is a wave graph for a 10 hp 220 V motor going through kick start, soft start, full voltage Power On Time and energy saving. 9

10 I 92 Kick start 57 Soft start Rated current Full voltage Saving mode t Fig. 3.a 4. Features DIGITEK-IIIGS is designed for three-phase fixed speed induction squirrel cage motors for general purposes with the following features: Energy saving Soft-start Soft-stop Kick-start Rapid load change reaction Low voltage protection High voltage protection Phase loss protection Over current protection Remote motor start-stop control External bypass 10

11 5. Specifications Input power voltage: Three-phase 220V / 380V / 440V / 480V ±10% Rated current: 30A / 60A / 90A / 120A / 180A / 250A Input power frequency: 50Hz ±10% Ambient temperature: -40ºF ~ 113ºF (-40ºC ~ 45ºC) Low voltage protection: Rated Voltage Low Voltage Resuming Saving V 220V 195V 205V 380V 345V 355V 440V 405V 415V 480V 440V 450V *When the input voltage is equal or below the low voltage specified above, the output voltage is the same as the input voltage and there is no saving. High voltage protection: Rated Voltage High Voltage 220V 290V 380V 490V 440V 570V 480V 620V *When the input voltage is equal or higher than the high voltage, DIGITEK-IIIGS stops the output and stops the motor. The motor will not be restarted automatically again. 11

12 6. Models Models No Rated Voltage Allowed Voltage Max Current Frequency TGS5030A V 200VAC~240VAC 30Amps 50Hz TGS5060A V 200VAC~240VAC 60Amps 50Hz TGS5090A V 200VAC~240VAC 90Amps 50Hz TGS5120A V 200VAC~240VAC 120Amps 50Hz TGS5180A V 200VAC~240VAC 180Amps 50Hz TGS5250A V 200VAC~240VAC 250Amps 50Hz TGS5030A V 350VAC~430VAC 30Amps 50Hz TGS5060A V 350VAC~430VAC 60Amps 50Hz TGS5090A V 350VAC~430VAC 90Amps 50Hz TGS5120A V 350VAC~430VAC 120Amps 50Hz TGS5180A V 350VAC~430VAC 180Amps 50Hz TGS5250A V 350VAC~430VAC 250Amps 50Hz TGS5030A V 400VAC~480VAC 30Amps 50Hz TGS5060A V 400VAC~480VAC 60Amps 50Hz TGS5090A V 400VAC~480VAC 90Amps 50Hz TGS5120A V 400VAC~480VAC 120Amps 50Hz TGS5180A V 400VAC~480VAC 180Amps 50Hz TGS5250A V 400VAC~480VAC 250Amps 50Hz TGS5030A V 440VAC~550VAC 30Amps 50Hz TGS5060A V 440VAC~550VAC 60Amps 50Hz TGS5090A V 440VAC~550VAC 90Amps 50Hz TGS5120A V 440VAC~550VAC 120Amps 50Hz TGS5180A V 440VAC~550VAC 180Amps 50Hz TGS5250A V 440VAC~550VAC 250Amps 50Hz 12

13 7. Installation 7.1 Safety Guidelines a. Before installing the DIGITEK-IIIGS Motor Controller, make a thorough visual inspection of the unit for signs of damages as a result of shipping or handling. b. Verify that proper circuit breakers (fuses) required for protecting the wiring and load are installed on the AC Input side of the unit. The DIGITEK-IIIGS motor controller starts the output to start the motor 3 seconds after the input power is switched on. As a consequence the possible damage on the contactor at close due to the high inrush current can be avoided. c. The DIGITEK-IIIGS should be installed and adjusted by qualified technicians. d. Installation of capacitors for enhancement of power factors should be done by qualified technicians. e. Before switching on the power, all the wiring should be thoroughly inspected to make sure that all of the wirings are properly and correctly connected. 7.2 Notes on Installation a. Choose the right DIGITEK-IIIGS model according to the size of the motor. The rated current of the DIGITEK-IIIGS motor controller should be higher than that of the motor. b. Mount DIGITEK-IIIGS at a proper location sturdily with good ventilation. c. Use copper connection wires for better signal transmission. d. Adhere to all requirements applicable to this type of installation as specified in National Electrical Code (NEC). Strict compliance to state and local codes should also be observed. e. DIGITEK-IIIGS should be installed as close to the motor as possible to retain clear signal transmission. f. Avoid electronic devices between the DIGITEK-IIIGS and the motor to avoid signal interference. All control wires such as those for Y- magnetic contactors should be connected before DIGITEK-IIIGS or should have independent power supply in order to maintain proper voltage supply to the contactors. g. DIGITEK-IIIGS should not be used with inverter to avoid serious damage. h. Phase loss protection and soft start are applicable to one motor with one DIGITEK-IIIGS application. i. The energy saving percentage is larger at lower load. The same machines with the same load might result in different energy savings. 13

14 j. For a motor continuously with high load motor the energy saving possibility is low. In general, a motor at load with power factor higher than 0.65 has minimal energy saving possibility. 7.3 Installation Diagrams Basic installation diagrams DIGITEK-IIIGS can be operated without soft-start. In that case the motor might be started with full voltage or with other voltage reduction devices such as Y- starter. The control wires of the magnetic contactors for motor on-off control or the Y- starter should be connected before the DIGITEK or with independent power supply in order to maintain proper voltage for the magnetic contactor control. Fig. 7.a and 7.b are for full voltage start as well for soft start. Fig. 7.c is for a system with Y- starter. R S T NFB MC L1 L2 L3 DIGITEK-IIIGS M1 M2 M3 MOTOR F1 F2 OFF ON MC OL MC Fig. 7.a 14

15 15 Fig. 7.b Fig. 7.c R S T MOTOR DIGITEK-IIIGS L1 L2 L3 M1 M2 M3 MC F1 F2 OFF ON MC MC OL NFB R S T MOTOR DIGITEK-IIIGS L1 L2 L3 M1 M2 M3 MCM F1 F2 OFF ON T OL NFB MCR MCS T T MCR MCS MCS MCM U V W X Y Z MCM MCR MCS

16 7.3.2 Installation diagram with remote control system R S T Motor on-off indicator R S T Remote motor on-off control AC input for Indicator * DIGITEK-IIIGS BYP COM DT-III * The voltage of the AC input for the indicator depends on the voltage of the indicator. R S T MOTOR Fig. 7.d 16

17 7.3.3 Installation diagram with external bypass system AC IN CT1 R S T CT2 Motor on-off indicator CT3 R S T Remote motor on-off control AC input for Indicator * DIGITEK-IIIGS BYP COM DT-III b MC OUTPUT a R S T b MC BYPASS a AC input for MC control ** R S T R S T * The voltage of the AC input for the indicator depends on the voltage of the indicator. MOTOR ** The voltage of the AC input for the MC control depends on the voltage specification of the MC. Fig. 7.e 17

18 8. Setup and Operation 8.1 LCD Display Page Function Range Default Setting Front Page Software No. CC Status 1 Status Indication 1 Status 2 Status Indication 2 P01 Soft Start Set On Off Off P02 Start Voltage P03 Soft Start Time 01 3C 05 P04 Kick Set On Off Off P05 Kick Voltage P06 Kick Time P07 Power On Time 00 FF 05 P08 Soft Stop Set On Off Off P09 Stop Voltage P10 Soft Stop Time 00 FF 14 P11 Optimum Autosave 6A P12 Max Voltage Drop P13 Semiauto V Drop P14 Ext Bypass Set On Off Off P15 Full V Current P16 Low Voltage 46 6E 5C P17 Over Voltage 6E P18 Remote Control On Off Off P19 Over Load Bypass On Off Off P20 Rapid V Recovery P21 C I Sensitivity P22 Auto S Response *All of the parameters are hex system: 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E, 1F and so on. 18

19 8.2 Choice of Parameters Frontage XXX A ~ Rated Current of DIGITEK-IIIGS, f. g., 120 A is for DIGITEK-IIIGS with rated current 120 A. Status 1 K ~ Set Kick Start On. S ~ Set Soft Start On. P ~ Set Power On Time On. T ~ Set Soft Stop On. E ~ Set External Bypass On. R ~ Set Remote Control On Lv ~ Lv appears when input voltage is over low (P16) and disappears when voltage returns to saving mode. Fc ~ Fc appears when the current is under full voltage operation (P15) and disappears when saving mode is resumed. Ci ~ Ci appears when current is rapidly increased (P21). Pl ~ Pl appears when there is phase loss and disappears when the phase loss is corrected within 30 seconds. Ob ~Set the Over Load External Bypass( P19) On. Status 2 19

20 F=XX ~ Input power frequency, f. g., when the input power frequency is 50, it shows F=32. Ov ~ Ov appears when the motor is stopped due to over high voltage (P17). Oc ~Oc appears when the motor is stopped due to over current. Ps ~ Ps appears 30 seconds after phase loss. a. Without external bypass system, the motor will further continue to run for 30 seconds and then stop. After the first 30 seconds of phase loss Ps appears and will not disappear until the input power of DIGITEK-IIIGS is turned off. b. With external bypass system, the system turns into by system after 30 second of phase loss and Ps appears. If there is also phase loss in the bypass system the motor will be stopped 30 second after switching into to the bypass system. Ps will not disappear until the input power DIGITEK-IIIGS is turned off. Rm ~ The motor in operation has been started with remote control. P01: Soft Start Set Set at On to start the motor with soft-start. Default setting: Off. P02: Start Voltage a. The range for start voltage: 10 ~ 64. b. Default setting: 32. This is the highest soft start voltage for larger motor or heavier load. c. The smaller the parameter is, the large the starting voltage is. The choice of this parameter depends on the size of the motor and the load of the motor at start. Usually 40 with some fine adjustment might be good for 50 hp motor without load or with low load. d. When the starting voltage is too low, the initial torque might be too small to start the motor. On the other hand, when the starting voltage is too high, it 20

21 reduces the soft start effect and the starting current might not as low as wanted. P03: Soft Start Time a. Range for soft start time setting: 01 ~3C. b. Default setting: 05. c. 01 means 1 second for soft start time. Each increment is for 1 second up to 60 seconds. The soft start time should be enough for completing the soft start. Usually 5 to 10 second should be enough. P04: Kick Set a. This feature should be accompanied with soft start. b. When a motor has a rather high load at start, it needs a larger initial torque to start the motor. Kick-start provides a larger starting voltage for a very short period to provide the motor enough initial torque, then the soft start takes over. c. Default setting is Off. Set Kick Set at On to start the motor with kick-start. P05: Kick Voltage a. Range for kick-start setting: 05~32. b. Default setting: 05. c. The smaller the parameter is, the larger the kick-start voltage is. The best choice is that the current is as low as we want but with the initial torque enough to start the motor. Usually 05 for the kick-start voltage should be good enough. 21

22 P06: Kick Time a. Range for kick-start time setting: 05 ~ 32 cycles. b. Default setting: 05 cycles. c. Each increment for kick-start is 1 cycle. For 05, the kick-start time is 5 cycles. P07: Power On Time a. Range for Power On Time setting: 00 ~ FF. b. Default setting: 05. c. After the soft start is completed, one can have the power on time for the motor to run smoothly before entering into saving mode. In the case without soft start, the power on time starts as the motor starts. Each increment is 1 second and the longest is 225 second. For example, 05 means that 5 seconds after the completion of the soft start it enters the saving mode. The key pad setting is as follows: i. 1 ~ 30 seconds: every time increase or decrease 1 increment. ii. 30 ~ 255 seconds: every time increase or decrease 2 increments. d. With external bypass system, the power on time, P07, starts start as the motor starts. After the power on time the DIGITEK-IIIGS takes over and enters into the saving mode. P08: Soft Stop Set Set at On to stop the motor with soft stop. Default setting: Off. 22

23 P09: Soft stop voltage a. The range for stop voltage: 20 ~ 64. b. Default setting: 56. This is the largest soft stop voltage. c. Larger parameter is for smaller stopping voltage. P10: Soft Stop Time a. Range for soft stop time setting: 00 ~FF. b. Default setting: 14. c. 01 means 1 second for soft stop time. Each increment is for 1 second. The voltage drops to the stopping voltage within the stop time. P11: Optimum Autosave a. This is for optimum automatic saving adjustment in the automatic saving mode. b. Range for optimum automatic saving setting: 6A ~ 90. c. Default value: 73. d. On the automatic saving mode, one can make a fine-tuning to get the overall best saving. For lower Optimum Autosave parameter the energy saving is better for all load. However, to ensure the motor operates smoothly, one may set it at the

24 P12: Maximum Voltage Drop a. Range for maximum voltage drop: 30 ~ 64. b. Default setting: 64. c. The maximum voltage drop is the maximum voltage drop at the lowest load. Usually we allow the output voltage to drop as much as possible in order to obtain the largest saving. Sometime when the maximum voltage is set too low, the motor might not function properly at high load. P13: Semiauto V Drop a. Range for Voltage drop setting at semiautomatic saving mode: 05 ~ 64. b. Default setting: 05. c. This is the output voltage setting for semiautomatic saving mode. This is mostly used for motor with load near constant. The larger the parameter is, the larger the voltage drop is. d. In principle we can set the output voltage as low as possible to get the better saving. We can also set at the semiautomatic mode for test purpose. e. When the parameter is set too large, the voltage can continue to drop but the current might increase. In this case the voltage drop is too big and one should set the parameter smaller such that the current will not increase as the voltage drops. This should be the best energy saving setting for that load. f. For certain load, if the voltage drop is too large, i.e. the output voltage is too low, the torque might not be enough for that load and so the motor stops. P14: External Bypass Set 24

25 a. When an external bypass system is installed, one can set the External Bypass On and start the motor via the bypass system. After the completion of the start, it automatically enters the saving mode. b. Default setting: Off. c. This feature is applicable at automatic start mode. During the starting period, BYPASS LED is On. After the power on time set in P07, DIGITEK-IIIGS takes over the operation, and at the same time the DIGITEK ON LED turns on and the operation enter into saving mode. d. For the installation diagram with external bypass system please see Fig. 5.e. P15: Full V Current a. Range for full voltage current setting: 14 ~20. b. When the load is close to full, there is small possibility for energy saving. To make sure that the motor will continue to operation smoothly near full load, the motor operates with full voltage near full load. c. Full load current in hex system is 20, equivalent to 32 in decimal system. Default full voltage current setting is 20 in hex system, equivalent to 32 in decimal system or rated current of the DIGITEK-IIIGS unit. In most of the case this should be a good setting. d. When the motor is running with full voltage current Fc appears. Otherwise Fc disappears. P16: Low Voltage a. Range for Low voltage protection setting: 46 ~6E. b. Default setting: 5C. c. When voltage is below the low voltage value, the saving mode will be switched off and the output voltage will be the same as the input voltage. One may alter the low voltage setting by increase or decrease the parameter. However, to alter the low voltage value it is important to consult with qualified technician. 25

26 When the input voltage returns to the resuming voltage or higher, it reenters into the saving mode. Rated Voltage Low Voltage Resuming Saving V 220V 195V 205V 380V 345V 355V 440V 405V 415V 480V 440V 450V P17: Over Voltage a. Range for over voltage protection setting: 6E ~ 96. b. Default setting: 84. c. When the input voltage is higher than the high voltage, DIGITEK-IIIGS will stop the output and stop the motor immediately. The motor will not be automatically restarted when the voltage is returned to the voltage lower than the high voltage. Rated Voltage High Voltage 220V 290V 380V 490V 440V 570V 480V 620V P18: Remote Control a. One may start and stop the motor remotely with the remote control on automatic start mode and automatic saving mode. b. Default setting: Off. c. Diagram for remote control system see Fig. 7.d, and diagram for remote control system with external bypass system see Fig. 7.e. 26

27 P19: Over Load Bypass For special purpose, when an additional over load protection bypass system independent of DIGITEK-IIIGS is added, P19 should set to On. For the details, please consult DIGITEK. P20: Rapid V Recovery a. Range for rapid voltage recovery setting: 00 ~30. b. Default setting: 18. c. To make sure that there is enough quick recovery on voltage for quick increase on the load, P20 allows the adjustment of to what voltage to be recovered. The larger the umber is set, the smaller the voltage will be recovered. When it is set at 00, it returns to full voltage. P21: C I Sensitivity a. Range for current increase sensitivity setting: 04 ~18. b. Default setting: 14. c. When the load is rapidly increased, so does the current. It then requires a quick recovery of voltage to provide enough voltage for torque needed. P21 set how fast is the current increase for rapid voltage recovery. d. Rated current is 20 in hex system, equivalent to 32 in decimal system. The default setting is 14, equivalent to 20 in decimal system. This means that the system will return to full voltage when the current is creased 20/32 of rated current within 0.25 second. For example, for DIGITEK-IIIGS with rated current 120 Amps, the system returns to full voltage operation if the current 27

28 increases 120 x 20/32 = 75 Amps within 0.25 second. Notice that the full voltage here is the rapid recovery voltage set at P20. P22: Auto S Response a. Range for automatic saving response: 01 ~04. b. Default setting: 01. c. For some rapid regular load changing system, it might require faster reaction in automatic saving mode in order to obtain better saving result. One of the applications of this mechanism is to oil pump jack with faster strokes. 8.3 Setup Procedures Control keyboard: DIGITEK LCD MOTOR CONTROLLER DIGITEK-IIIGS AUTO MANUAL START BYPASS ON DIGITEK ON SAUTO MANUAL FULL V STATUS ENTER Notations: AUTO\MANUAL ~ On Automatic starting mode, LED on. (AUTO\MANUAL) ~ On manual starting mode, LED off. SAUTO\MANU ~ On automatic saving mode, LED on. (SAUTO\MANU) ~ On manual saving mode, LED off. START ~ On automatic starting mode, hit Start for the first time start. DIGITEK ON ~ DIGITEK ON is on and LED is on. (DIGITEK ON)~ DIGITEK ON is off and LED is off. 28

29 BYPASS ON ~ BYPASSS ON is on and LED is on. (BYPASS ON) ~ BYPASS ON is off and LED is off. REMOTE CONTROL ~ Remote control is on. (REMOTE CONTROL) ~ Remote control is off. AUTO\MANUAL: For automatic or manual start control. a. Manual start: When the LED for AUTO\MANUAL is off, one can start the motor manually. b. Automatic start: When the LED is on, the motor can be started as follows: i. DIGITEK-IIIGS input power: Turn on the DIGITEK-IIIGS input power, set AUTO\MANUAL AT automatic saving mode and then hit START key, the motor will be started automatically. The motor will be stopped as the input power is switched off. When the input power is switched on again, the motor will be started again automatically. ii. Remote control: After the DIGITEK-IIIGS input power is switched on, key in the Auto\manual to automatic starting mode, i.e. the LED light on the far left is on, one can start the motor by switching on the remote control switch. START: At automatic start mode and the remote start is not used, key in START for the first time start after the input power is switched on. The motor can be stopped and restarted as follows: When the motor is stopped by turning off the input power, it can be restarted automatically by turning on the input power. BYPASS ON: a. Without external bypass system: i. Set the EXT BYPASS in LCD P14 at OFF. ii. On automatic starting mode: the motor starts with full voltage and then enters into the saving mode after the power on time. Action: BYPASS ON AUTO\MANUAL START * When AUTO\MANUAL is set on automatic mode first, the status of BYPASS ON key can t be altered. Restarting motor: When the DIGITEK-IIIGS input power is switched off, the motor stopped. When the DIGITEK-IIIGS input power is switched on again, the motor starts as set previously. iii. On manual starting mode: Hit BYPASS ON and then hit DIGITEK ON, the motor starts with full voltage and will not enter energy saving mode until BYPASS ON is set off. To stop the motor, set DIGITEK ON off. 29

30 b. With external bypass system: i. Set EXT BYPASS in LCD P14 at ON. ii. On automatic starting mode: On automatic starting mode, hit START to start the motor through external bypass circuit. After power on time it switches to DIGITEK-IIIGS and enters saving mode automatically. iii. On manual starting mode: On manual starting mode, the motor starts through the external bypass circuit as BYPASS ON is set on. Set DIGITEK ON makes DIGITEK-IIIGS take over the operation and further set off BYPASS makes the DIGITEK-IIIGS enter the energy saving mode. The motor can be stopped by key in DIGITEK ON, i.e. by setting DIGITEK ON off. SAUTO\MANUAL: Hit SAUTO\MANUAL for automatic saving or semiautomatic saving. When the LED at the far left is on, it is on the automatic saving mode, otherwise it is on the semiautomatic saving mode. DIGITEK ON: On manual start mode, i.e. the top far left LED is off, start and stop the motor with DIGITEK ON without going through bypass circuit. FULL V: When this key is hit with the LED on the left on, the output is always with full voltage, the same as the input voltage. STATUS: Hit this key to go to the status page. ENTER: After the new parameter value is selected, hit ENTER for the new parameter setting. : Hit this key to go to previous page. : Hit this key to go to the next page. : Hit this key to increase the parameter value. : Hit this key to decrease the parameter value. Setup procedures: a. Under the manual starting mode, set the parameters for kick start, soft start, and power on time. i. Kick start: Based on the size of the motor and the load at start decide whether the kick start is needed or not. The larger the load at start is, the larger kick start voltage and the kick start time are required. ii. Soft start: Based on the required starting current limit adjust the starting 30

31 voltage and the starting time. Smaller soft start current requires lower starting voltage and longer soft start time. The soft start time should be enough to complete the soft start. If the soft start time is not enough to complete the soft start, then after the soft start time the motor will continue the starting process under full voltage with higher current. Whether the motor start smoothly during the start process can tell whether the soft start time is enough. I Rated current Fig. 8.a Soft start without enough soft start time. t I Rated current Fig. 8.b Soft start with enough soft start time. t iii. Power On Time: The POWER ON TIME is to let the motor to have enough time before entering smooth phase of the machine. In general, smaller motor requires shorter power on time. b. After the setting of the starting parameters mentioned above, one can set the parameters for automatic saving and manual saving. c. After the setting of starting parameters and saving parameters, make a test on the automatic start. d. Under the automatic saving mode, test the remote start-stop control. e. Under the manual starting mode, one can go directly to the page for that parameter setting and do the setting without altering other parameters. 31

32 8.4 Operation procedures a. Manual start + automatic saving i. Start motor: SAUTO\MANUAL + DIGITEK ON ii. Stop motor: (DIGITEK ON) or (BYPASS ON) b. Manual start + semiautomatic saving i. Start motor: (SAUTO\MANUAL) + DIGITEK ON ii. Stop motor: (DIGITEK ON) or (BYPASS ON) c. Automatic start + automatic saving i. First time start: AUTO\MANUAL + SAUTO\MANU + START ii. Stop motor: The motor can be stopped in three ways, a) Switching off input power. b) Switching of remote control. c) Set the AUTO\MANUAL at manual, i.e. the AUTO\MANUAL LED is off, then turn off DIGITEK ON or BYPASS ON off. After switching from automatic start mode to manual start mode, the motor can t be started automatically anymore. iii. Restart motor: When it is at the automatic starting mode, the motor can be restarted automatically in two ways, a) Switching on DIGITEK-IIIGS input power. b) Switching on remote control. d. Automatic start + semiautomatic saving i. First time start: AUTO\MANUAL + (SAUTO\MANUAL) + START ii. Stop motor: The motor can be stopped in three ways, a) Switch off DIGITEK-IIIGS input power. b) Switch off remote control. c) Set the AUTO\MANUAL at manual, i.e. the AUTO\MANUAL LED is off, then turn off DIGITEK ON or BYPASS ON off. After switching from automatic start mode to manual start mode, the motor can t be started automatically anymore. iii. Restart motor: When it is at the automatic starting mode, the motor can be restarted automatically in two ways, a) Switch on DIGITEK-IIIGS input power. b) Switch on remote control. e. Remote control start and stop i. Remote control works only on automatic start with automatic saving or semiautomatic saving mode, i.e. AUTO\MANUAL + SAUTO\MANU or AUTO\MANUAL + (SAUTO\MANU). 32

33 ii. Start motor: REMOTE CONTROL. iii. Stop motor: (REMOTE CONTROL). f. Protection mechanism starting setting reset When the protection mechanism, such as over current protection, phase loss protection or over voltage protection, is activated and the DIGITEK-IIIGS stops the output to stop the motor, the starting setting will be reset to manual starting mode. Any starting mode other than manual setting has to be reset. g. Summary of different processes to start a motor DIGITEK-IIIGS can start a motor in the following ways: i. For a large motor with heavy load at start, it might require a short kick start to overcome the high torque at start. It is then followed by soft start to maintain low current during the start. After completion of soft start, it enters Power On Time for delay saving to let the motor have enough time to run smooth before entering saving mode. Finally it enters energy saving mode. Kick Start Soft Start Power On Time Saving Mode ii. For a larger motor or a motor with larger motor, in order to avoid large inrush current, it can be started with soft start to maintain low starting current during the motor start. It is then enters Power On Time and finally to energy saving mode as described in i. Soft Start Power On Time Saving Mode iii. Start motor with full voltage. After completion of motor start, it enters Power On Time for delay saving. Finally it enters energy saving mode. For a motor start with other motor starter such as Y- starter, DIGITEK-IIIGS should be installed before the starter with the control wired connected before DIGITEK-IIIGS or to independent power source and start the motor with full voltage to DIGITEK-IIIGS. Full V Power On Time Saving Mode 8.5 Phase loss protection a. Phase loss protection works only when the running current is 1/6 or higher of the rated current. 33

34 b. Input power phase loss: With external bypass circuit: After 30 seconds, it switches to bypass circuit for 30 seconds, then the external circuit will be switched off and the motor will be stopped. Without external bypass circuit: After 60 seconds, the motor is stopped. c. Motor phase loss: With external bypass circuit: After 30 seconds, it switches to bypass circuit for 30 seconds, then the external circuit will be switched off and the motor will be stopped. Without external bypass circuit: After 60 seconds, the motor is stopped. d. DIGITEK input or output phase loss: With external bypass circuit: After 30 seconds, it switches to bypass circuit and the motor continues to run. Without external bypass circuit: After 60 seconds, the motor is stopped. 8.6 Over current a. When the current is over the rated current continuously for 300 seconds, the motor will be stopped. b. The higher the over current is, the faster the motor will be stopped. 8.7 Energy saving adjustment a. Semiautomatic saving mode: At semiautomatic saving mode, one may adjust the semiauto V drop (Voltage drop at semiautomatic saving mode) in P13. When the value is larger, the voltage and the current will be dropped more, and one get larger energy saving. However, when the parameter is set too large, the voltage can continue to drop but the current might increase. In this case the voltage drop is too big and one should set the parameter smaller such that the current will not increase as the voltage drops. This should be the best energy saving setting for that load. b. Automatic saving mode: i. Optimum Autosave: On automatic saving mode, the voltage and current increase as the load increases and vise versa. On the automatic saving mode, one can make a fine-tuning to get the overall best saving. For lower Optimum Autosave parameter the energy saving is better for all loads. However, to ensure the motor operates smoothly, one may set it at the

35 ii. Maximum voltage drop: This is a parameter for setting the maximum voltage drop. In principle, one would like to have the voltage drop as much as possible at low load. Set this parameter at 64 should be a good choice. However, to ensure a smooth operation of the motor one might set the parameter smaller to have smaller maximum voltage drop. c. Switching between automatic and semiautomatic saving: When the motor is running, one can switch between automatic and semiautomatic saving freely. 35

36 Appendices Appendix A: Horse Power, KW, and Rated Voltage and Current Three-Phase 220V 380V 440V HP KW Current (A) Current (A) Current (A)

37 Appendix B: Hex Numbers VS Decimal Numbers Hex Decimal Hex Decimal Hex Decimal Hex Decimal Hex Decimal A 26 3A 58 5A 90 7A 122 9A 154 1B 27 3B 59 5B 91 7B 123 9B 155 1C 28 3C 60 5C 92 7C 124 9C 156 1D 29 3D 61 5D 93 7D 125 9D 157 1E 30 3E 62 5E 94 7E 126 9E 158 1F 31 3F 63 5F 95 7F 127 9F A A A A A A A A A A A 42 4A 74 6A 106 8A 138 AA 170 2B 43 4B 75 6B 107 8B 139 AB 171 2C 44 4C 76 6C 108 8C 140 AC 172 2D 45 4D 77 6D 109 8D 141 AD 173 2E 46 4E 78 6E 110 8E 142 AE 174 2F 47 4F 79 6F 111 8F 143 AF

38 Appendix C: Capacitors and Energy Saving C.1 Power Factor The intrinsic inductance of a motor causes the lagging of the current behind the voltage. The cosine of the angle of this phase difference, denoted by cosθ with θ the angle of the phase difference, is usually called the power factor. The power factor varies as the load varies. For different motors the power factor can also be different because of their design. The existence of the intrinsic inductance of a motor results in a split of the total power, KVA, supplied by the utility company, into the real power, KW, which is what is actually consumed by the motor, and the reactive power, KVAR, which is also known as magnetizing power. The total power is also known as apparent power and the working power as active power. The total power, the real power and the reactive power for single-phase system are related as follows: And KW = KVA x cosθ KVAR = KVA x sinθ KVA 2 = KW 2 + KVAR 2 KVA is the total power supplied by the utility company to the user. KW is the actual power consumed by the motor and is the basic charge by the utility company to the user. This actual power is transformed into the mechanical energy to carry out the mechanical work, the heat dissipation of the motor and the vibration and friction of the motor. It is clear that the higher the power factor the closer the total power to the actual power. Therefore, for a motor with higher power factor the wasted reactive power is lower. C.2 Demand Charges The requirement for lowering the reactive power or equivalently the total power imposed by utility companies to the users has become more popular recently. This is usually known as the demand charge. There are three demand charges in practice imposed by different utility companies. C.2.1 KVAR Demand Charge This is a direct charge on the excessive reactive power, KVAR. Consider a plant with a demand of 1800 KVA, 1350 KW and 1200 KVAR. If the KVAR charge is $1.50 per 38

39 month for each KVAR of demand in excess of 1/3 of the KW demand, we may compute the KVAR demand charge as follows: Calculate KVAR demand in excess of 1/3 of the KW demand, 1200 KVAR 1350KW/3 = 750 KVAR. Estimated annual demand charge on the excess KVAR, $1.50 x 750 KVAR/month x 12 months = $13, The KVAR demand charge can be eliminated or reduced by improving the power factor. An improvement on the power factor decreases the KVAR. However, it is important to point out that an improvement on the power factor does not decrease the KW consumed by the motor. C.2.2 KW Demand Charge Consider a plant with a demand of 1,000 KW and an 80% power factor. The serving utility has a target power factor of 85 % and a KW demand charge. The KW demand charge is calculated as follows: Calculate the amount of the monthly KW billing. (1,000 KW x.85 target pf)/.80 existing pf = 1062 KW, $9.00 /KW demand charge x 1062 KW = $9, billing. The demand charge can be reduced if the power factor is improved. First calculate the KVAR required for improving the power factor to 85%. As will be explained in the next section, simply multiply the KW by the factor obtained from TABLE II. The factor to calculate from.80 to.85 power factor is x 1000 KW = 130 KVAR (required KVAR to meet 85% target pf). With an installation of capacitors with size of 130 KVAR, the amount of KW billing demand with new power factor is: (1000 KW x.85 target pf)/.85 new pf = 1000 KW billing demand. Therefore $9.00 KW demand charge x 1000 KW = $9,000 billing, Saving in KW demand charge 39

40 80% of KW billing $9,558, 85% of KW billing $9,000, Monthly saving $ 558. C.2.3 KVA Demand Charge Consider a plant with 400 KW and 520 KVA demand. A demand charge is based on KVA. This KVA demand can be reduced if the power factor is raised. The present power factor = KW/KVA = 77% (a low power factor). When we install capacitors to raise the power factor to 95%, the KVA is then reduced. And Reduced KVA = KW/new power factor = KW/.95 = 421 KVA, Saved KVA = 520 KVA 421 KVA = 99 KVA. For $3.00/KVA demand charge we have $3.00/KVA x 99 KVA = $ saving per month. We then have $297.00/month x 12 month = $ saving per year. In all this calculation, KW remains the same. An improvement on power factor can reduce the reactive power KVAR and in turn the total power KVA. The KW remains the same. C.3 Power Factor Enhancement We have seen that a power factor improvement indeed can help to reduce the demand charge and in turn the billing charge. A further application of power factor enhancement is to reduce the line loss and therefore to save energy. The enhancement of capacitor can t save the energy consumption of a motor. However, enhancement of power factor can result in reduction of current. Since the line loss is 40

41 proportion to I 2 (squire of current), therefore the reduction of current can result in smaller line loss between the capacitor and the watt-hour meter. The question is how to install the capacitors. The question is how to install the capacitor. First of all we have to choose appropriate capacitor size. We suggest that the power factor should be raised to 85% to 95%. For a motor with changing load, to void too much capacitance on high load, we suggest that the size of the capacitor should be evaluated at high load. TABLE C.3 makes it simple to find the size of the capacitors in KVAR needed to improve the power factor from its present level to the desired value. Find the original power factor in the left vertical column, follow this line to the right until you reach the column of desired power factor. This resulting figure times KW = KVAR of capacitors required to improve from one power factor to another. First of all we have to choose appropriate capacitor size. We suggest that the power factor should be raised to 85% to 95%. For a motor with changing load, to void too much capacitance on high load, we suggest that the size of the capacitor should be evaluated at high load. 41

42 TABLE C.3 Cos 0.8 DESIRED POWER FACTOR Cosθ UNIT Application example: Conversion of KVAR toµf: C (µf) = KVAR 10 9 ORIGINAL POWER FACTOR Motor Load: 50 KW Original Power Factor: Cosθ 1 = 0.6 Desired Power Factor: Cosθ 2 = 0.95 Capacitors needed = 50 1,005 ( from Table II) = 50 KVAR 2πf E 2 2πf = 314 for 50 Hz 2πf = for 60 Hz where KVAR = Capacitor Size in KVAR f= Frequency in Hz E= Rated Voltage V 42