Application Guide

ManualsBrandsHoneywell ManualsHVAC SuppliesSmart VFD HVAC Variable Frequency Drive, 208/230V, 2 HP, NEMA 1, Drive Alone

63-7062

Variable Frequency Drive (VFD)

APPLICATION GUIDE

CONTENTS

SAFETY..............................................................................................3

When Installing this Product..........................................................3

Inspection Procedure.....................................................................3

Monitor the LED............................................................................. 3

INTRODUCTION ................................................................................ 4

VFD Types..................................................................................... 4

Why Buy a VFD ............................................................................. 4

Where are VFD Applications .........................................................4

Benefits Summary..........................................................................5

VFD MARKET..................................................................................... 5

Energy Costs .................................................................................5

VFD Costs......................................................................................5

What’s New.................................................................................... 5

User Benefits .................................................................................6

MOTOR FUNDAMENTALS ................................................................7

Advantages.................................................................................... 7

Disadvantages...............................................................................7

Voltage and Current Waveform Examples .................................... 8

Differences Between Star Delta and Delta Star............................. 12

Load Types....................................................................................14

Power Factor..................................................................................15

Useful Formulae ............................................................................16

VFD FUNDAMENTALS ...................................................................... 16

Construction...................................................................................16

Braking Resistor ............................................................................17

VFD Voltage to Frequency Ratio. .................................................. 18

Charging Resistor..........................................................................19

AC Line Choke............................................................................... 19

Motor and VFD Tests..................................................................... 20

INSTALLATION GUIDELINES............................................................ 24

General Guidelines........................................................................24

Surveying....................................................................................... 24

VFD Location: Enclosures and Ventilation ....................................24

EMC Wiring and RFI Filters...........................................................25

Line Reactors.................................................................................26

RFI......................................................................................................26

Sources Of Emissions ...................................................................26

Routes for Emissions..................................................................... 27

Equipment Categories ...................................................................28

General Wiring Standards .............................................................28

APPLICATIONS.................................................................................. 29

VFD OVERVIEW ................................................................................30

Application Description .................................................................. 30

Benefits.......................................................................................... 31

VFD Features Used ....................................................................... 31

Operation (See Fig. 36) ................................................................. 31

Constant Air Volume with Air Quality Compensation (See Fig. 37)32

Operation.......................................................................................33

Variable Air Volume (VAV) Primary Plant Control (See Fig. 40).... 34

Cooling Tower Fans (See Fig. 41).................................................35

Application Description .................................................................. 35

Benefits.......................................................................................... 35

VFD Features Used ....................................................................... 36

Operation (See Fig. 42) ................................................................. 36

Primary Chilled Water Option 1 (See Fig. 43 and 44) ................... 36

Summary of content (54 pages)

PAGE 1
Variable Frequency Drive (VFD) APPLICATION GUIDE CONTENTS SAFETY.............................................................................................. 3 When Installing this Product... ....................................................... 3 Inspection Procedure..................................................................... 3 Monitor the LED ............................................................................. 3 INTRODUCTION ............................................................
PAGE 2
Primary Chilled Water Pump with DDC Control of Plant Option 2 (See Fig. 45 and 46) ...........................................................................................37 Secondary Chilled Water Pump Option 1 (See Fig. 47).................39 Secondary Chilled Water Pump with DDC Control Option 2 (See Fig. 48) .......................................................................................................40 Heating Secondary Water Circuit (See Fig. 49) .............................
PAGE 3
SAFETY When Installing this Product... 1. 2. 3. 4. Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition. Check the ratings given in the instructions and on the product to make sure the product is suitable for your application. Installer must be a trained, experienced service technician. After installation is complete, check out product operation as provided in these instructions. WARNING Electrical Shock That Can Cause Death.
PAGE 4
INTRODUCTION VFD Types The following list gives mechanical, electrical and hydraulic VFD examples (many have a considerable mechanical content needing regular maintenance): 1. Mechanical Drives. a. Adjustable sheave belt drive. b. Clutch. c. Traction drive. 2. Electrical Drives. a. Eddy—current clutch. b. DC (rotating and solid state). c. Solid state Vac. d. Multi-speed motors. 3. Fluid drives.
PAGE 5
Benefits Summary — — — — — — Improved control. Reduced plant wear. Quieter operation at low load. Reduced complaints. Lower operating costs. Typical payback period is less than 2 years. VFD MARKET Energy Costs The forces for industrial automation, requirements for ever increasing efficiencies from plant and machinery, together with demands for higher performance at a lower cost, continue to fuel rapid VFD market growth.
PAGE 6
Honeywel RUN lREADY FAULT MON PAR REF BTNS RST PG Programmable Multiple Digital & Analogue Inputs Programmable Multiple Digital & Analogue Outputs RS232 Interbus S Profibus Echelon Option Card Fig. 2. VFD Functionality.
PAGE 7
General Purpose Spindle Drive Vector Drive Honeywel RUN lRE AD Y FAULT Honeywel RUN lRE ADY FA ULT MON P A R RE F BTNS Honeywel RUN lRE ADY FAULT MON P AR RE F B TNS RS T PG DC Drive Honeywel RUN lRE ADY FA ULT MON P A R RE F BTNS RST MON P AR RE F B TNS RS T PG PG RST PG Honeywel RUN lRE ADY FA ULT MON P AR REF B TN S RS T PG Universal Drive Fig. 3. Universal Drive.
PAGE 8
Voltage and Current Waveform Examples No Load Fig. 4 shows the current and voltage waveforms of one phase of a standard three-phase 10 Hp induction motor under no load conditions. Full load current of the motor is 13.5 amps from a 415 supply. It is clear from the graph that even under no load conditions the motor draws substantial current. Phase L1 400 10 300 7.5 200 5 Amps V 100 o l 0 t -100 s A m 0 p s -2.5 2.5 Voltage -200 -5 -300 -7.
PAGE 9
Sine Wave Supply Voltage to Frequency Relationship The motor nameplate carries several important parameters: kW or HP, voltage, full-load current, full-load motor speed, and power supply frequency. Two of these, terminal voltage and power supply frequency are very important as they define the voltage to frequency ratio for the motor. This creates a constant flux (magnetic field) condition throughout the full speed range of the motor. The voltage to frequency relationship is a simple linear relationship.
PAGE 10
Factors Affecting Motor Temperature and Insulation Life As indicated earlier, three-phase electric motors are extremely rugged machines. With few moving parts sealed from the local environmental effects, except temperature, the motor can be expected to provide reliable service for many years. When discussing this subject with end users, often the comments made are significantly different.
PAGE 11
Vibration Ventilation Waveform Rated Temperature Rise Frequency Motor T Insulation t Life Load (Duty Cycle) Voltage Ambient Altitude Fig. 9. Causes for insulation failure. Three of the elements in Fig. 9 can be or are affected substantially by application of a VFD. Therefore, they have a bearing on the temperature of the motor and thus its life expectancy: Vibration Although a modern VFD produces good quality current waveforms, there is a small amount of additional vibration produced at the motor.
PAGE 12
During starting, mechanical stresses increase rapidly with increases in motor sizes. Mechanical failure through metal fatigue is common on large machines that are started too frequently. When a VFD is applied to a motor, surge current is almost eliminated depending on the inertia of the load and the time required for the motor to reach full or required speed. The result is that there is virtually no limit to number of motor starts per hour, regardless of size.
PAGE 13
Star Delta Star Delta is a method to reduce applied voltage to the stator winding starting large motors (see Fig. 10). This reduces starting current. This also reduces locked rotor torque. Both power and current in Star are less. 240v Applied 240v 415v Fig. 10. 415V phase windings in Star. Delta 415v 415v Fig. 11. 415V phase windings in Delta. Full nameplate Power available in Delta (see Fig. 11). Delta Star A method to produce a Dual Voltage motor. See Fig. 12. 240v 240v Fig. 12.
PAGE 14
Load Types There are four basic load types: Constant Torque Care is required. Examples are: cranes, elevators, agitators, mixers, and conveyors. The torque remains constant throughout the range of speed of operation. This application is probably the most difficult for a general purpose VFD. It requires the motor to produce full load torque at zero speed. Rarely can a general purpose VFD provide this capability.
PAGE 15
Centrifugal pumps and fans operate like this. Power changes sharply with small speed changes. 150 125 %Torque/ 100 Power 75 50 Torque Power 25 0 25 50 75 100 125 150 % Speed Fig. 15. Cube law torque load torque/power curve. Constant Power Type Loads Not usually encountered in HVAC industry. Examples are machine tools. Care must be taken at all times. If a mistake is made in type of load identification then the application will be at best troublesome and at worst a failure. See Fig. 16.
PAGE 16
Device Incandescent Lamp Neon Lamp Fluorescent Lamp (w/Stabilizer) Radio Table 2. Power Factor of Some Devices. Power Factor Device 100% Single Phase Induction Motor 40%-50% Three Phase Induction Motor 90% Table Top Fan 100% Ceiling Fan Power Factor 60%-80% 70%-90% 60%-80% 50%-60% Useful Formulae Motor speed = (Supply frequency * 120) / Number of motor poles The above formula provides the synchronous (no load) speed of the motor. However, as load is applied to the motor, it begins to develop slip.
PAGE 17
AC Choke M Control Computer Charging Resistor Fig. 17. VFD Construction. Braking Resistor Under normal circumstances, with the motor under load, the flow of energy through the system is from the commercial power supply to the VFD and from the VFD to the motor and finally from the motor to the load. There are operating conditions where the load tries to over run the motor. An example of this would be a high inertia load.
PAGE 18
Braking Resistor M Control Bus Monitoring Circuit Fig. 18. VFD braking resistor. Pulse Width Modulation (PWM) Control Principles Various methods produce a synthesized three-phase power supply suitable for driving a standard three-phase electric motor. However, the industry has standardized on the PWM method of control. See Fig. 19. Fig. 19. Pulse Width Modulation. VFD Voltage to Frequency Ratio.
PAGE 19
100% Te rm ina l Vo lta ge Design Max Motor Torque Field Weakening Point Motor Torque De sig n Ma x Sp ee d Auto Boost Fixed Boost Motor Speed 100% Theoretical Terminal Voltage Fig. 20. VFD voltage to frequency ratio. Charging Resistor The charging resistor is included in the DC bus to provide current limiting during the initial power up stages of the VFD.
PAGE 20
Phase L1 400 10 300 7.5 Voltage 200 5 V 100 o l 0 t -100 s A m 0 p s -2.5 2.5 Current -200 -5 -300 -7.5 -400 -10 0 2 6 4 8 10 12 Time ( ms ) 14 16 18 20 7.5 kW Motor No Load Fig. 21. Motor voltage and current under no load conditions. Note the shape of the current waveform in Fig. 21 with respect to the voltage. It is the non sinusoidal format of the current waveform that causes the harmonics on the network and can ultimately cause voltage waveform distortion.
PAGE 21
Test 1. Motor Run with Varying Loads on Commercial Power Supply Fig. 23 indicates performance of a standard squirrel cage motor driven directly by a commercial power supply at 100%, 66% and 33% load. On 100% load, motor body temperature rises quickly to 64°C, while ambient temperature remains stable around 20°C. When the load is reduced to 66%, body temperature quickly falls to 45°C, as expected under reduced load conditions.
PAGE 22
Test 3. Motor Run on VFD with Fan Load Simulation. The purpose of this test is to prove that the motor will not suffer harmful effects of overheating, when driving a fan or pump type centrifugal load at varying speeds. The dynamometer was configured to produce similar characteristics to those of a centrifugal fan. The motor was then run up to 50 Hz an the load adjusted to 100%. After a short time, it can be seen from Fig.
PAGE 23
7.5 kw 4 pole 110 15 Hz 100 20Hz 30 Hz 90 °C 40Hz 80 70 50Hz Temp Sensor 1 60 50 Temp Sensor 2 40 30 Ambient 20 Fig. 26. Motor on constant full load torque. Test 5 Motor Run on Old and Modern-Design VFDs at 50 Hz on Full Load torque. As a final test, Fig. 27 shows a comparison in the heating effects of running a motor first on a 10 year old design VFD and a modern VFD.
PAGE 24
INSTALLATION GUIDELINES General Guidelines — — — — — — — — — — — — — — — — — — — — — — — Do not install a VFD in a hazardous or flameproof area. Do not install a VFD to drive motors installed in hazardous areas. This requires special testing and approvals. Every Honeywell VFD has a three-phase output. Do not assume that all three-phase AC motors can be driven by a general purpose VFD. Some types require a special VFD. Do get full motor name plate details - do not assume anything.
PAGE 25
Where the environment is dusty and in particular if the dust is of a conductive nature, then the cooling air should be filtered prior to injection into the VFD enclosure. Again, if the environment is particularly dirty, the enclosure may be sized to provide sufficient natural cooling or a refrigeration unit may be installed. Refer to the technical manual for the individual machine for specific details on mounting and spacing between machines.
PAGE 26
Line Reactors Line reactors can be used on both VFD inputs and outputs. Input Line Reactors The installation of a large number of VFDs or other similar equipment can distort the current and voltage waveforms of the power supply, to the point which exceeds the power supply company guidelines or to the a level that other equipment served by this power supply is prevented from operating correctly. In such a case, including input line reactors provides additional smoothing to that provided by the DC choke.
PAGE 27
Routes for Emissions The main route for the RF energy is out through the VFD output terminals. See Fig. 29. Radiation Supply Drive Motor Winding Capacitance u v w Safety Earth Lead RF Current Machinery and Building Cable Capacitance Fig. 29. Emission routes. Without Input Filter The VFD can be considered as a source of radio frequency (RF) current which leaves the output terminals.
PAGE 28
Equipment Categories Non Sensitive Equipment falling into this category are simple electromechanical device: — Relays. — Contactors. — Electric motors. — Solenoid devices. Care Required Many electronic devices are insensitive to VFD emissions due to the spectrum at which this interference is generated and the ability for the target equipment to locally filter out the noise.
PAGE 29
Where control signal cables need to cross VFD input and output cables this should be done at right angles with no parallel runs. See Fig. 33. Incorrect Correct Inverter Filter Filter Inverter Coupling will Occur here Inverter Filter Inverter Inverter Filter Inverter Inverter Filter Inverter Filter Fig. 33. Locating filter and VFD control signal cables. Filter Location Fig. 33 adjacent shows various VFD and filter installations.
PAGE 30
EXCEL VRL APPLICATION GUIDE APPLICATIONS — — — — — — — — — — Fans. Pumps. Mixers. Boilers. Compressors. Conveyors. Elevators. Machine Tools. Textile machinery. Paper and film manufacturing. VFD OVERVIEW Honeywell has long been aware of the full benefits of VFDs, and has installed them in a wide range of applications from fans, pumps, and compressors to machine tools, elevators and textile machines.
PAGE 31
Benefits — — — Reduced running costs - typical savings 40% and 14 months payback, dependent on power consumption. Maintenance savings arise from running the motor at reduced speed which lowers the load torque; lessens mechanical stress on belts, bearings. Environmental comfort increased as a result of reduced air velocity - less draughts - and lower background noise levels. VFD Features Used — — — Soft Start - Reduced starting current and avoids pressure surges.
PAGE 32
Constant Air Volume with Air Quality Compensation (See Fig. 37) M RUN Honeywel l READY FAULT MON PAR REF CO2 or AQ BTNS RST PG RUN Honeywel l READY FAULT MON PAR REF BTNS RST PG M M DP - + T T DP TS s M T Honeywell Controller One Inverter could be used, but two is a better option. EMC Fig. 37 Application Diagram.
PAGE 33
VFD Features Used — — — — Power failure recover. Speed search. Possible DC injection on start. Overspeed capability for increased performance. IMPORTANT Ensure minimum number of air charges per hour is still met, by using VFD low limit. Operation Control Output t OA < t t OA > t 100 Fan Speed OA Damper Legend Temperature Control Min Fan Speed Fan Speed Control Heating Cooling Dampers Min OA Damper ZEB ZEB Temperature t Setpoint Fig. 38 Sequence of Control: Temperature.
PAGE 34
Variable Air Volume (VAV) Primary Plant Control (See Fig. 40) x Honeyw ell RUN READY FAULT Honeyw ell RUN READY FAULT MON MON M PAR REF PAR REF BTNS BTNS RST RST PG PG M DP M T s + M TS T T M PS Honeywell Controller EMC Fig. 40. Application Diagram. Application Description A Variable Air Volume (VAV) system controls the space temperature by varying the volume of supply air, rather than the supply air temperature.
PAGE 35
VFD Features — — Soft Start: Reduced starting current and avoids pressure surges. Motor Speed Low Limit: Minimum air movements levels programmable. Cooling Tower Fans (See Fig. 41) Cooling Tower M Bypass Valve Condenser Water System Honeywel lREADY FAULT PAR REF BTNS RST T Condenser Honeywell System Chilled Water RUN MON PG EMC Controller Inverter Evaporator Fig. 41. Application diagram.
PAGE 36
VFD Features Used — — — — Power failure recovery. Speed search. Possible DC injection on start. Overspeed capability for increased performance. IMPORTANT In multi-fan applications under VFD speed control, all fans should operate in unison. Operation (See Fig.
PAGE 37
Evaporator 1 Inverter RUN Honeywel l READY FAULT MON PAR REF BTNS RST PG M V1 CC1 M V2 CC2 Evaporator 2 Fig. 44 Application with VFD. Application Description Chillers with evaporators piped in parallel (see Fig. 43) and controlling on either flow or return from the machine. Often, under light load conditions, chiller two will close down (to prevent short-cycling).
PAGE 38
Inverter RUN Honeywel FAULT l READY MON PAR REF Controller BTNS RST CC1 Evaporator 1 PG M V1 CC2 Evaporator 2 M V2 Fig. 46 Application with VFD and Excel Plus Application Description If the chillers in the previous example (option 1) are controlled on the flow from the machine and also have Direct Digital Control or a building management system installed on the air handling and chiller plants, an even more efficient and effective means of control is available.
PAGE 39
IMPORTANT Very careful calibration of controllers is required to ensure that the chillers are safeguarded under all conditions. The chillers built-in controllers will still control at their original value. The supply temperature to building will not change. When starting the second chiller, the isolating valve must be opened as slowly as possible, to prevent the on machine tripping under low flow condition. Secondary Chilled Water Pump Option 1 (See Fig.
PAGE 40
Secondary Chilled Water Pump with DDC Control Option 2 (See Fig. 48) M V2 Secondary Chilled Water T T T 1 2 M V1 RUN Honeywel l READY FAULT MON PAR Honeywell REF BTNS RST PG EMC Inverter Controller C1 V1, V2 = Mixing Valve Primary Chilled Water Fig. 48. Application diagram.
PAGE 41
Heating Secondary Water Circuit (See Fig. 49) Secondary Hot Water T 2 T 1 M RUN Honeywel l READY FAULT MON PAR REF Honeywell BTNS RST V1 PG EMC Inverter Controller C1 V1 = Mixing Valve Primary Hot Water Fig. 49. Heating secondary water circuit application. Application Description Conventional Control Valve V1 is modulated by controller C1 with sensor T1 located in the secondary hot water flow. The objective is to give a constant supply temperature at T1.
PAGE 42
Steam Boiler Make-Up Pump (See Fig. 50 and 51) to System Steam Level Transmitter Boiler 1 Water Level Control M RUN Honeywel l READY FAULT MON PAR REF BTNS RST PG M P from System INVERTER Micronik 100 Receiver Fig. 50. Single boiler, single pump application. to System Steam Steam LT Boiler 1 Water LC M Steam LT Boiler 2 Water LC LT Boiler 3 Water LC M M RUN Honeywel l READY FAULT MON PAR REF BTNS Honeywell RST PG M EMC P from System Inverter Receiver Fig. 51.
PAGE 43
Boiler Flue Gas-Induced Draught (ID) Fan (See Fig. 52) Chimney/Stack PS Common Flue M T T M T M RUN Honeywel lREADY FAULT MO N PAR REF BTNS RST PG Boiler #1 Boiler #2 Boiler #3 Micronik 100 Inverter Fig. 52. Boiler flue gas ID fan application. Application Description Traditionally a damper in the common flue from all boilers is controlled by a static pressure sensor located before the ID fan.
PAGE 44
Boilers and Forced Draught Fan (See Fig. 53) 3UHVVXUH 7UDQVPLWWHU Pressure Regulator Main Gas Boiler Manual Valve Pilot Gas Gas Control Valve M RUN Honeywel l READY FAULT MON PAR REF BTNS RST PG 7DNH FDUH WR HQVXUH DOO VDIHW\ GHYLFHV RQ WKH ERLOHU VWLOO IXQFWLRQ DIWHU FRQYHUVLRQ Excel VRL 3URILOH &RQWUROOHU ,QGXVWULDO &RQWUROOHU Fig. 53. Boiler with forced draught fan application.
PAGE 45
Aircraft Passenger Jetty Loading (See Fig. 54) Skirt P/D ow n In/O ut C ontrol Pow er U ltrasonic D etector M otor/G earbox Inverter Fig. 54. Aircraft passenger jetty loading application. Application Description With the existing control system the jetty is started by hand and the operator drives the jetty out towards the aircraft.
PAGE 46
VFD Features Used — — — — — Digital or analog speed control. Stall prevention. Forward - reverse. Variable torque. Overtorque trip. IMPORTANT Existing safety limits must not be altered. Screw Press (See Fig. 55) Wet Product Screw Press Variable Pitch Pullies Motor 37kW Dry Product Manual Adjustment Mechanism To Process Fig. 55. Screw press application. Application Description A screw press is used to reduce the moisture content of a wet product.
PAGE 47
VFD Features Used — — — — — — — Auto restart. Over speed. Over torque. Stall prevention. Analog or digital control. Forward/reverse for clearing blockages. Variable torque control. IMPORTANT Ensure that the VFD can handle the breakaway toque of the load. It may be necessary to select one size larger VFD than the motor to achieve this. Elevators (See Fig.
PAGE 48
Starting is also coarse as the motor is generally switched directly on to the power supply causing harsh acceleration. By interfacing a VFD to the existing control, smoother starting is achieved and stopping is more precise. These both to accuracy of approximately 1.5 mm. This is a fully controlled stop, so it is a repeatable process.
PAGE 49
POST POWER UP CHECKS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Power the VFD (with output disconnected). Ensure that all input phases are present and the display is correct. Refer to the device technical manuals for details. If all is well, power down and wait until the DC bus voltage has decreased to a safe level. Reconnect the output cables. Power the VFD again, ensuring that the stop command is present in the VFD terminal.
PAGE 50
A simple check for stable control from the VFD is to install a temporary control potentiometer, (maybe 15 - 20K ohms in value) using the VFD power supply, usually 10 or 15 Vdc and 0V (ground). Connect the ends of the potentiometer to the DC power supply and to 0V ground and connect the wiper of the potentiometer to the voltage speed reference input. Vary the setting of the potentiometer and monitor the reference value on the VFD display for stability.
PAGE 51
Minor Faults VFD Overheat This fault is usually caused by problems with cooling air circulation over the VFD heat sink or within the VFD chassis. It may also be caused through a combination of high motor load and high ambient temperature. The outcome of the above is that the VFD has sensed that its internal components have become overheated and has closed down, in order to prevent thermal damage. 1.
PAGE 52
Switches on output of VFD Isolating switches or contactors will often be located in the output cables from the VFD. As when switching an inductive load, an arc develops at the point where the contact first breaks. This arc can cause high voltage spikes, as high as 3-4 kV, on the cables back to the VFD. The high voltage spike can completely disrupt the DC bus voltage monitoring circuit, causing a false high DC bus voltage trip.
PAGE 53
Closing a Switch on a Running VFD Output There are no electrical defects in the circuit. It is caused by incorrect programming and application. If the VFD is running and a switch is closed in the output cables from the VFD, the motor and VFD will try to effect a direct on-line (DOL) start. Typically, surge currents in excess of 6 times full-load motor current flow during a DOL start. The VFD has a normal rating of 150% of its nameplate current for one minute and 200% current for 0.5 seconds.
PAGE 54
Miscellaneous Control Power Terminals The VFD will generally have an on board power supply for use with external equipment e.g. transmitters. A simple voltage check of this power supply together with an other terminals that output voltages will give a good indication of the state of the control board. Use of Multiple Auto Resets Most VFDs have a function which provides auto reset in the event of a trip. This function is designed to enhance the reliability of the VFD service provided.