Instructor Guide - Transit Training Network

Instructor Guide

214: Elevator: Electrical SystemsModule 7: Drive Motor Circuits

Elevator – Drive Motor Circuits Instructor’s Guide

Table of Contents

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Overview……………………………………………………………………………………………..…..……....4 Drive Motors……………………………………………………………………………………………………14 Drive Power Circuits………………………………………………………………………………………….33 Motor Protection and Faults, Starters……………………………………………………………………..54 Wiring Configurations………………………………………………………………………………………...73 Motor Replacements…………………………………………………………………………………............82 Summary………………………………………………………………………………………………………..87

Elevator – Drive Motor Circuits Instructor’s Guide Icons Used In This Guide Agenda

Topic # Topic Title Duration

Total Time:

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1

2

3

4

5

Overview

Drive Motors

Drive Power Circuits

Motor Protection, Faults, Starters

Summary

30 Minutes

60 Minutes

60 Minutes

90 Minutes

60 Minutes

30 Minutes Motor Replacements

Wiring Configurations

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7

30 Minutes

30 Minutes

450 Minutes

60 Minutes 8

9

Field Trip

Field Trip

Elevator – Drive Motor Circuits Instructor’s Guide

Overview Purpose The purpose of this module is to:

Objectives At the end of this lesson, the transit elevator/escalator trainee will be able to:

Materials Mandatory Make sure you have the following

Optional You may also want the following for optional activities:

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Provide the participant with an overview of the circuits that operate the drive motor system.

• PowerPoint Presentation • Coursebook • Quizzes • Pencils

• Chalk board with chalk, large paper with marker, etc.

• Internet connection • Lab, simulator or out of service elevator • Sample starters • Examples of various motors and drives

• Identify the types of drive motors associated with each type of elevator system.

• Describe the types of overload protection and their method of operation.

• List and describe the different types of possible motor faults.

• List and describe the different types of starters. • Identify and trace the wiring configuration for a drive

motor using a schematic. • Describe the method used to change out a drive motor

specific to the elevator.

Elevator – Drive Motor Circuits

DO SAY Materials Needed

Instructor’s Guide

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Instructor’s Notes

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Module Length: 450 min Time remaining: 450 min This section: 30 min (11 slides) Section start time: ________ Section End Time: ________

Welcome to the course on Elevator Electrical Systems, Drive Motors. Advance Hopefully you will never encounter this, and this module is a step in the direction of knowing elevator drive motor systems and how to avoid this situation. Advance

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Today we will - Identify the types of drive motors associated with each type of elevator system. - Describe the types of overload protection and their method of operation. - List and describe the different types of possible motor faults. - List and describe the different types of starters. - Identify and trace the wiring configuration for a drive motor using a schematic. - Describe the method used to change out a drive motor specific to the elevator. Advance

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Lets take a look at some of the key words we will be defining as move through this module: - AC variable-voltage/variable-frequency (VVVF) - DC silicon-controlled rectifier (SCR) - DC pulse-width modulation drives (PWM) - alternating-current (AC) - bi-metallic Thermal Overload Relay - direct-current (DC) - drive motor - drive systems - line Side - load Side - motor overload protection Advance

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- overload Section - resistance Temperature Devices - running protection - short circuit protection - slip velocity - solid-state overload relays Advance

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PPT slide 6 Thinking back to previous elevator courses, or elevator technical experiences in general, what do we know about elevator motor systems, drives, and their electrical components? [Allow participants to think for a minute and perhaps discuss with a partner ideas as well as write down any ideas. Discuss participant responses and if possible list them on a chalk board or similar.] Advance


ASK participants

SMALL GROUP ACTIVITY

WRITE

Optional: Chalkboard/chalk or Paper/marker




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PPT slide 7 You may recall from earlier courses this figure and the drive system in the elevator is the muscle. This system is comprised of the motor, drive and related controls that help to lift and lower the elevator car. In a hydraulic system there is also a pump and related mechanisms. Advance

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PPT slide 8 You may also recall this earlier diagram showing the elevator control circuits. The part of the system we will be focusing on in this module will be the lift system within the elevator unit. [Discuss diagram with participants. Electrical power is supplied to the system: the control system, the lift system, the cab, and the hoistway. User commands are sent to the control system via the user interface. These commands are distributed to the lift system for operation, and feedback is sent back to the control system from the cab and hoistway and eventually back to the user to alert the use of the position and movement of the elevator.] Advance

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PPT slide 9 Elevator drive systems are required to not only accelerate and decelerate at speeds which provide a smooth ride for the passengers but they must also meet the need of accurate positioning when stopping at each landing. Cost is also a consideration when choosing the type of elevator installation for a facility. Modern techniques with solid-state drive technology have helped to somewhat reduce the costs of installation and long-term maintenance. Within transit systems there are two basic types of elevator drive systems: Advance hydraulic and Advance electric. [Ask: What are the differences between hydraulic and electric systems? Use the diagrams to assist participants with their responses.] Advance

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PPT slide 10 In electric elevator systems, the elevator motor drive adjusts motor torque output to achieve desired acceleration, deceleration, and travel speed independent of car loading. The drive's efficiency is an important component of overall elevator efficiency. Outdated, inefficient drives that may be part of existing elevator systems but are no longer on the market include alternating-current (AC) two-speed, AC variable-voltage, and direct-current (DC) motor-generator sets (Ward Leonard). Modern, efficient drives include AC variable-voltage/variable-frequency (VVVF), DC silicon-controlled rectifier, and DC pulse-width modulation drives (PWM). Advance

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PPT slide 11 Hydraulic elevator drives incorporate a motor, pump, control valve system to move the elevator between levels. A hydraulic elevator’s rate of rise is determined by the specific installation but the same principles apply with regard to acceleration and deceleration. In this module, we will look at the drive motor systems and their controls in the various electric traction and hydraulic installations. Advance

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Lets start this module off by taking a look at the different types of drive motors encountered in elevator systems. You may recall motor generators are made up of an AC induction motor and a DC generator. AC motors are known to have difficulty in controlling the speed; therefore it was common to use this system with a gearbox (known as a geared traction system). However, the use of AC variable frequency drives has made the use of AC systems without a gearbox more efficient (gearless systems). This has led to the use of machine and brake systems being connected directly to the top of the elevator car (Direct Drive System). Do Not Advance

PPT slide 12 REVIEW slide

Internet connection

Multimedia




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[Multi-media: At instructor discretion and if time permits, click on the photo of the motor to link to website HowStuffWorks.com to review motor basics.] Advance

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Internet connection

Multimedia




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PPT slide 13 The two types of motors found in transit elevator systems are a Direct Current (DC) motor/generator set providing dc power for the dc motor, or an Alternating Current (AC) Induction motor with a drive. These motors and their drives are typically housed in what is known as the elevator machine room. Advance

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PPT slide 14 Early electric-traction elevator systems used DC motor/generator sets. These generator-field controls were used to operate the elevator, and some are still around today. In these early elevator systems, the DC motors operated by generating a force between the interaction of a magnetic field and current-carrying conductors. As an electric current passes through a current-carrying wire bent into a loop with two right-angles, the magnetic field experienced forces in opposite directions. The electromagnetic arrangement, or field coils, produce the magnetic field. By passing the current through this arrangement, the opposing forces then created a torque, or turning force, to rotate the coil. Do Not Advance

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PPT slide 14 Motors typically have several coils to provide a uniform torque. These motors were found in machine rooms located near the elevator shaft and offered excellent speed and control. Today, the DC motor/generator sets are not seen very often in the transit industry and are usually limited to mid and high-rise building elevator systems. Typically in the transit industry, three phase induction motor are used in elevator systems. Advantages to the AC induction motor includes no brushes or commutator for easier manufacturing, no wear, no sparks, no ozone production and associated loss of energy Advance

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PPT slide 15 An induction or asynchronous motor is a type of AC motor where power is supplied to the rotor by means of electromagnetic induction. A squirrel-cage induction motor is one in which the rotor is electrically isolated from the stator. In overall shape, the squirrel-cage rotor is a cylinder mounted on a shaft. Internally it contains longitudinal conductive bars (usually made of aluminum or copper) set into grooves and connected together at both ends by shorting rings forming a cage-like shape. The name is derived from the similarity between this rings-and-bars winding and a squirrel cage (or, as it is commonly known, a hamster wheel). Advance

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PPT slide 16 The stator windings of an AC induction motor are distributed at 120o intervals around the stator to produce a roughly sinusoidal distribution. When three phase ac voltages are applied to the stator windings, a rotating magnetic field is produced. When the three currents flow through the three symmetrically placed stator windings, these sine waves distribute a magnetic flux across the air gap between the stator and the rotor generating sinusoidal currents within the rotor. The interaction of the sinusoidal wave form distributed air gap magnetic flux and induced rotor currents produces a torque on the rotor. The rotating magnetic field of the stator forces the rotor to turn. Do Not Advance

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PPT slide 16 The rotor does not quite keep up with the rotating magnetic field of the stator. It falls behind or slips as the field rotates. The mechanical angular velocity of the rotor is lower than the angular velocity of the flux wave by so- called slip velocity. Advance

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PPT slide 17 A limited number of internal components mean fewer problems in three phase AC induction motors than their DC counterparts. Three-phase motors have fewer components that may malfunction than other motor types. Therefore, three-phase motors usually operate for many years without any problems. If a three-phase motor is the problem, the motor is serviced or replaced. Servicing usually requires that the motor be sent to a motor repair shop for rewinding. An example of a good servicing practice is, if the motor is less than 1 HP and more than five years old, it is replaced. If the motor is more than 1 HP, but less than 5 HP, it may be serviced or replaced. If the motor is more than 5 HP, it is usually serviced. Do Not Advance

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PPT slide 17 Induction motors are widely used in transit escalator drives, particularly three-phase induction motors, because they are robust and have no brushes. Their speed can be controlled with a variable frequency drive. With standard direct-on-line (DOL), the speed of an AC induction motor is determined by two factors: - Number of pole windings in the motor - The frequency of the line voltage source. Since it is very difficult to change the number of physical poles in motors larger than ½ horsepower, the only means of controlling the speed is through the use of a variable frequency voltage source. With the advent of newer solid-state devices, variable frequency drives are now capable of developing the power necessary to drive large horsepower motors. Advance

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PPT slides 18, 19 [Enrichment: At the instructor’s discretion and if time permits, review the motor diagram with participants.] Advance [Enrichment: At the instructor’s discretion and if time permits, review the rotor diagram with participants.] Advance

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PPT slides 20 [Discuss: Share the example photo of the AC induction motor found in a transit station machine room in Washington Metropolitan Area Transit Authority.] Advance

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PPT slide 21 In adjustable speed applications, many AC motors are powered by variable frequency drives (VFD). The VFD converts low frequency (60 Hz) AC to DC and then inverts the DC power to a pulse width modulated (PWM) AC power at the required frequency and amplitude. The inverter consists of three half-bridge units (one per phase) where the upper and lower switches are controlled complimentarily. During the switching process, the solid-state power device's turn-off time is longer than its turn-on time, some dead-time must be inserted between the turn-off of one transistor (or SCR) of the half-bridge and turn-on of its complementary device. Advance

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PPT slide 22 The output voltage is created by a pulse width modulation (PWM) technique. The three-phase voltage waves are shifted 120° to one another similar to the incoming line waveforms however, that is where the similarity ends. These simulated drive outputs can now be controlled through the microprocessor’s PLC that controls the drive units. With this type of drive, it is now possible to control not only the amplitude of the waveforms but, the frequency of the waveform is variable as well. Advance

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PPT slide 23 More advanced system use permanent-magnet AC motors that are slightly more efficient and smaller than induction motors. These motors require a high-efficiency variable-frequency drive and contain fewer moving parts. Sometimes, these motors are mounted directly in the elevator shaft which eliminates the need for a machine room. In this case, the elevator is known as a machine room-less elevator and is ideal for low-rise buildings where space is a premium, such as in the transit industry. Advance

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PPT slide 24 Lets see what we have learned so far: Not typically found in today’s transit elevator systems, early elevator systems used ___________________ drive systems. a. AC VVVF b. DC Motor/Generator Sets c. DC PWM d. DC SCR Call on participants for answer Advance once given the correct answer Answer: b. Advance


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PPT slide 25 The mechanical angular velocity of the rotor is lower than the angular velocity of the flux wave by so- called __________________. a. set frequency b. set velocity c. slip frequency d. slip velocity Call on participants for answer Advance once given the correct answer Answer: d. Advance


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PPT slide 26 List three advantages of an AC Motor. Call on participants for answer Advance once given the correct answer Answer: - Fewer internal parts means fewer problems - Robust and no brushes - Solid-state devices allow development of power to drive large horsepower motors Advance


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PPT slides 27, 28 Jim has not heard about the latest and most modern drive motor systems in elevators. How would you describe these modern systems to Jim? Call on participants for answer Advance once given the correct answer Answer: - More advanced system use permanent-magnet AC motors that are slightly more efficient and smaller than induction motors. These motors require a high-efficiency variable-frequency drive and contain fewer moving parts. Sometimes, these motors are mounted directly in the elevator shaft which eliminates the need for a machine room. In this case, the elevator is known as a machine room-less elevator and is ideal for low-rise buildings where space is a premium, such as in the transit industry. Advance


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PPT slide 29 Found in all modern elevator installations is an electrical motor drive. The two types of motor drives that we see most often are relay logic in older installations and solid state consisting of Soft Start and the VVVF drive (Variable Voltage Variable Frequency) in newer installations. The simplest explanation as to the differences between the two is with a soft start unit is used in applications where the motor runs at a constant speed and the VVVF Drive is used when the speed of the drive motor needs to change. Advance

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PPT slide 30 Electric elevator drives can be either slow speed or high speed. These speed variations may be either controlled through the use of gear reduction or through the use of solid-state variable speed drive systems or a combination of both. Advance

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PPT slide 31 Electric elevator drives can be either slow speed or high speed. These speed variations may be either controlled through the use of gear reduction or through the use of solid-state variable speed drive systems or a combination of both. The advantage of an electric drive with gear reduction is that a high speed AC motor could be used to drive a fixed worm gear drive unit which would maintain a fairly constant speed. Gear driven elevators are normally used in low-rise situations. Their disadvantage is the power loss in the gear system is fairly high thereby lowering the overall efficiency of the system. In taller facilities high-speed multi-level elevators are required. Advance

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PPT slide 32 When an elevator is commanded to move from a resting position at its current floor a series of events occur. Power is applied to the drive motor by the control circuitry and the brake is released. The combined weight of the load is accelerated from a full stop to its maximum value. Ideally this maximum acceleration should occur smoothly in order to avoid jerking the car and causing any discomfort to the passengers. Full car acceleration in a single floor jump will depend on whether the drive is a slow speed gear drive or a high speed direct drive. Typically gear driven elevators will reach their contract speeds between floors. However high speed elevators normally do not reach their contract speeds in single floor jumps due to the acceleration rates of the drive system. Advance

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PPT slide 33 Elevator electric drives are typically electronic solid state drives and would be one of the following: Ward Leonard (AC motor-DC generator), Thyristor-Leonard (Silicon Controlled Rectifier), Variable Voltage (thyristors), Variable Frequency, and Variable Voltage/Variable Frequency (Insulated Gate Bi-polar Junction Transistors-IGBT), and Pulse-Width Modulation. Advance

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PPT slide 34 Ward Leonard Control, also known as the Ward Leonard Drive System, was a widely used DC motor speed control system introduced by Harry Ward Leonard in 1891. The configuration consisted of motor/generator conversion setup whereby a motor (it could be either AC or DC) moving at a constant speed is connected directly by its shaft to a DC generator. The output of the generator is fed to the DC drive motor of the elevator. Speed control was obtained through control of the generator field. The generator is a DC generator, with field windings and armature windings. By making small changes in current applied to the generator field, large changes in the output of the generator occurred, allowing smooth speed control. Do Not Advance

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PPT slide 34 Another advantage for this method is that the speed of the motor can be controlled in both directions of rotation. In addition the generator field excitation current could be removed quickly in an emergency which would reduce the generator output to virtually zero volts, thus causing the elevator car to move with full load at a low speed. However, today installation costs for this type of system are relatively high, space is needed for the motor/generator set, additional maintenance is required to provide upkeep for both the DC drive motor and the DC generator commutator and brushes. Additionally with power losses occurring within this drive network these were not the most efficient systems to operate. Advance

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PPT slide 35 By the early 1970s hybrid thyristors drive systems were being introduced to take the place of the motor/generator rotating conversion set. The principle power drive circuit consisted of two three phase power rectification circuits utilizing silicon controlled rectifiers (SCRs) as the conversion diodes. An SCR is a four-layered solid state semiconductor, or integrated circuit, which controls current. The advantage of this type of solid-state circuit was by being able to control the firing angle of the SCRs the rectified DC output of the power supply was made variable. Do Not Advance

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PPT slide 35 Another advantage of this type of circuit is that the SCRs could be switched off very rapidly (1msec) and reversed electrically to make it a passive convertor while still connected to the DC drive motor. This would allow the drive motor to be switched from a motor to generator thereby slowing the elevator drive system down rapidly by using the dynamic response of the generator effect. Replacing older motor-generator drives with modern drives not only reduces energy, but also improves indoor air quality as older systems used carbon drives leading to the presence of carbon particulates in buildings. Advance

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PPT slide 36 Variable Voltage (Thyristors) was the next drive to develop. With this type of drive, a two-speed motor is used. Speed is controlled by adjusting the AC voltage using SCR’s for movement with a positive load. To slow the motor speed down in the case of negative loads, speed is controlled by reducing motor input voltage and injection of DC current into the slow-speed windings. Generally, this type of drive system for use with hoist motors has been discontinued. Advance

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PPT slide 37 Variable Voltage/Variable Frequency Drives came along next. VVVF, or Variable Voltage/Variable Frequency, drives are typically used to convert old single-speed or two-speed AC systems. A VVVF drive controls the speed of an AC motor . When accurately matched to an AC motor, this drive has several features of a DC motor. Advantages to this type of drive include smooth acceleration and deceleration, excellent speed control, elimination of brush and commutator problems, and their ability to work on geared and in some cases gearless elevator. Advance

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PPT slide 38 Pulse-Width Modulation Another more recent variable speed drive is the Pulse-Width Modulation Drive, or PWM. The PWM drive offers a smooth, quiet operation through fast switching devices. Interference with other equipment is also improved. This drive operates by rectifying the incoming AC power which is then converted back to AC at a synthesized sinusoidal wave form through the switching device. Advance

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PPT slide 39 [Dicsuss: Share the example photo of a pulse width modulation drive in Washington Metropolitan Area Transit Authority.] Advance

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PPT slide 40 Using pressurized fluid to lift and lower the car, hydraulic elevators are typically used in low-rise transit installations (six floors and fewer). However, the modern generation of low cost, machine room-less traction elevators made possible by advances in motor and motor drive technology is beginning to challenge the supremacy of the hydraulic elevator in their traditional market role. All the same, hydraulic still plays a major role in the transit industry elevator systems. Do Not Advance

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PPT slide 40 For the car in a hydraulic system to rise, the car has a piston in a cylinder beneath or attached on the sides of the elevator car; the elevator lifts when an electric motor powers a hydraulic pump to pressurize a fluid (typically oil) the control valve directs the pressurized fluid into the cylinder, which displaces the piston up. To lower the car, the control system opens a valve and the fluid flows back into the tank as the weight of the car and the piston presses down on the hydraulic fluid. Advance

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PPT slide 41 In a conventional hydraulic drive, after the start signal, the motor (submerged or external) runs up from zero to maximum revolutions. The pump delivers the maximum possible flow. In order for the hydraulic piston to move the elevator car upward from a resting position and then to stop at the destination level the speed needs to be controlled. This is accomplished by using either a solenoid or an electronic control valve which allows excess oil to flow back into the storage tank. More oil is pumped than is effectively used. To move from the starting level and to stop at the destination level, elevator car speed needs to be controlled. Do Not Advance

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PPT slide 41 The leveling speed is obtained through the use of a hydraulic control valve. A hydraulic elevator using an electronic valve uses less energy than the same one using a mechanical valve. It is foreseeable that the mechanical valve will be rendered obsolete by further advances in the development of electronic control valves. A modern VVVF drive controls the valve and therefore controls the amount of oil required to move the piston and elevator car. The speed of the motor-pump combination is controlled directly by the VVVF drive, the same flow feedback signal is used as for the electronic valve. Advance

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PPT slide 42 Lets see what we have learned so far: Another name for a Ward Leonard drive system is a _____________________. a. Variable Voltage b. Variable Voltage Variable Frequency c. AC Motor/DC Generator Systems d. Pulse Width Modulation Call on participants for answer Advance once given the correct answer Answer: c. Advance


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PPT slide 43 An advantage of a AC Motor/DC Generator set is a. Requires large amount of space b. Speed of motor can be controlled in

both directions c. High cost d. Power loss is high Call on participants for answer Advance once given the correct answer Answer: b. Advance


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PPT slide 44 An advantage of a VVVF Drive is (check all that apply) a. Requires large amount of space b. Excellent speed control c. Works with geared and gearless

systems d. Elimination of brush and commutator

problems e. Smooth acceleration and

deceleration Call on participants for answer Advance once given the correct answer Answer: b., c., d., e. Advance


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PPT slide 45 [At instructor’s discretion, take time to visit the field and look for examples drive motor systems. Advance.

Module Length: 450 min Time remaining: 300 min This section: 90 min Section start time: ________ Section End Time: ________

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PPT slide 46 Occurrences that cause a motor to stop or become damaged are called motor faults. The types of motor faults that can occur include an over current fault, an under voltage fault, a ground fault, a breakdown in motor insulation, short circuits, an under speed fault, an over speed fault, and winding problems. Advance

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PPT slide 47 The first type of fault, an overcurrent fault, is the most common type of fault and occurs when an amperage to a device or component goes above what it is rated for. There are many causes for this type of fault, and the dynamics of the motor and load should be examined to help determine the cause. A cause for an overcurrent fault may be an under voltage to the motor. In this instance, the amperage goes above what the motor is rated for. An under voltage fault occurs when voltage goes below its rating. The breakdown of wiring insulation can create a motor fault known as a motor insulation breakdown fault. Advance

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PPT slide 48 Another fault, a short circuit occurs when a current does not follow its intended path. Two basic types of short circuits are a phase to phase and a ground fault. A phase to phase short circuit occurs when the insulation of two conductors of opposite polarities break down and the conductors come in contact with each other. A ground fault, takes place when any kind of current leakage to ground or chassis occurs. Under speed/Over speed faults occur when, a motor either goes too slow or too fast. Advance

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PPT slide 49 Winding problems and component failures are the last two types of possible motor faults. A winding problem occurs with the shortening of coil wires due to a breakdown in insulation. A component failure is the failure of the components of the electric drive. For instance, a component of the PLC may fail and cause the motor to stop working. A mechanical failure occurs when three is a degradation of motor bearings. An increase in temperature of the motor case could indicate a buildup of dirt within the windings or faulty windings. Advance

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PPT slide 50 Built into the design of the elevator is a system of overload protection. The National Electric Code (NEC) defines Motor Overload Protection as that which is intended to protect motors, motor-control apparatus, and motor branch-circuit conductors against excessive heating due to motor overloads and failure of the motor to start. In other words, overload protection is in place to protect major components from damage, and in the case of drive motors, the electronic components. Motor overload protection is also commonly referred to as “running protection”. Do Not Advance

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PPT slide 50 Motor overload protection is not intended to protect against motor branch-circuit short-circuit and ground faults. In a combination starter, this type of protection is provided by fuses, a circuit breaker, or a motor circuit protector (MCP). This protection is commonly referred to as “Short Circuit Protection” and is shown in the schematic below. Advance

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PPT slide 51 [Dicsuss: Share the example schematic displaying the locations in the circuitry of motor overload protection and short circuit protection.] Advance

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PPT slide 52 Overload protection for single and three-phase AC motors in the small (above 1 horsepower) and medium horsepower range is typically provided by one of two methods: bi-metallic thermal overload relays, or solid-state overload relays. Overload protection for large three-phase motors is sometimes provided by thermal overload relays which are connected to current transformers (CT’s). However, most new installations utilized microprocessor-based motor protective relays which can be programmed to provide both overload and short-circuit protection. Do Not Advance

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PPT slides 52, 53 These protective relays often also accept inputs from resistance temperature devices (RTD’s) imbedded in the motor windings (usually two per phase) and the relays are capable of displaying the winding and motor bearing temperatures, and provide both alarm and trip capability. Advance Starters are used for the purpose of providing a practical means of automatically or semi-automatically controlling the power supplied to the drive motor. In elevator systems, these starters will either be a magnetic across the line starter or a solid state starter. Advance

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PPT slides 54, 55 [Demonstrate: Briefly share the photo of the magnetic across the line starter.] Advance [Demonstrate: Briefly share the photo of the solid state starter.] Advance

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PPT slides 56 A Magnetic Line Starter (Across The Line Starter) consists of power lugs for connecting the supply wires known as the Line Side, as well as lugs for connecting the wire leads directly to the motor itself known as the Load Side designated as T1,T2, T3 in the same figure. It also contains a magnetic coil connected to the control circuit through an auxiliary contact which is used as a control means to either open or close its power contacts when it receives a signal from an external pilot device such as a Start/Stop Button station. This type of setup is considered to be semi-automatic as it requires an initial input from an external push button or pilot device. The final main section of a magnetic line starter is the Overload section. Do Not Advance

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PPT slides 56 Referring to Figure 9 they are designated as 1OL, 2OL, and 3OL for the motor’s power contacts and OL for the control circuit contact. These contacts are thermally activated in the event that motor becomes overloaded. As previously described, the overloads provide electrical protection for the motor by monitoring and sensoring the motor’s normal running current. In the event that the motor for some reason becomes overloaded, which means that it’s being worked beyond its design capability, the overload control contact will break the circuit to the magnetic coil or solid state control which then opens the power contacts to the motor bringing it to a stop thereby preventing any heat damage to the drive motor. Advance

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PPT slides 57 The final main section of a magnetic line starter is the Overload section designated as 1OL, 2OL, and 3OL for the motor’s power contacts and OL for the control circuit contact. These contacts are thermally activated in the event that motor becomes overloaded. As previously described, the overloads provide electrical protection for the motor by monitoring and sensing the motor’s normal running current. In the event that the motor for some reason becomes overloaded, which means that it’s being worked beyond its design capability, the overload control contact will break the circuit to the magnetic coil or solid state control which then opens the power contacts to the motor bringing it to a stop thereby preventing any heat damage to the drive motor. Advance

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PPT slides 58 [Demonstrate: Point out the various parts of the starter as illustrated on the schematic and described below.] Here is a schematic showing the power lugs for connecting the supply wires known as the Line Side designated as terminals L1, L2, L3, and you can see the lugs for connecting the wire leads directly to the motor again known as the Load Side designated as T1,T2, T3. You can see the magnetic coil connected to the control circuit as well as the Overload section designated as 1OL, 2OL, and 3OL for the motor’s power contacts and OL for the control circuit contact. Again, these contacts are thermally activated in the event that motor becomes overloaded. Advance

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PPT slides 59, 60 A solid state starter operates the same as a magnetic line starter except this type uses solid state means to control the motor’s power contacts. Advance [Compare: Point out the various parts of the starter as illustrated on the photo and described previously.] Advance

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PPT slide 61 The most common fault is a ____________________. a. Short circuit b. Under voltage fault c. Over current fault d. Motor insulation breakdown Call on participants for answer Advance once given the correct answer Answer: a. Advance


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PPT slide 62 Another name for motor overload protection is _________________. a. Running protection b. Bi-metallic Thermal Overload Relay c. Mechanical failure d. Stopping protection Call on participants for answer Advance once given the correct answer Answer: a. Advance


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PPT slides 63, 64 On the following schematic, identify the short circuit protection and motor overload protections. Call on participants for answer Advance once given the correct answer Answer: see diagram Advance


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PPT slides 65 Describe the similarities and differences between a magnetic across the line starter and a solid state starter. Call on participants for answer Advance once given the correct answer Answer: Starters are used for the purpose of providing a practical means of automatically or semi- automatically controlling the power supplied to the drive motor. A solid state starter operates the same as a magnetic line starter except this type uses solid state means to control the motor’s power contacts. Advance


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73

PPT slides 66 Wiring configurations are specific for each type of elevator and their drive system. The schematic we viewed in Starters a typical 3 phase motor wiring diagram. Configurations may vary due to the fact that each elevator installation is unique. To determine the differences if any, always refer to the wiring diagrams provided by the elevator installers with each installation. For a basic example, lets refer to the schematic for starters. Advance

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PPT slides 67 The top half of the schematic is designated by the heavy bold lines we see the drive motor’s power circuit. Advance The bottom half which is designated by the lighter lines is the drive motor’s control circuit. Both these circuits are interdependent upon each other for the successful starting and stopping of the drive motor. Advance

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PPT slides 68 Lets look at the power circuit first. Starting at the left side of the power circuit we see the 480volt 3 Phase 60Hz incoming power supply designated as L1, L2, and L3. (Line side 1, Line side 2, and Line side 3). Advance Next we see that the incoming power supply goes to a 3 phase fusible disconnect switch. This switch is commonly referred to as the Main Line Disconnect. Advance The Power Line Fuses in this case only provide short circuit protection and not overload protection to the conductors to the right of them. Advance

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PPT slides 69 Advance Leaving the fuses the power conductors go to the main power contacts on the motor starter which are the top half of the power contacts. These connectors represent the Line Side of the Motor Starter and are usually designated as L1, L2, and L3. Advance From the bottom half of the power contacts are usually designated as T1, T2, and T3, the power wires go to the top half of the Thermal Overloads contacts. This section is referred to as the Line Side of the Thermal Overload contacts. Advance The power wires then leave the Load Side or bottom half contacts of the Thermal Overloads and connect directly to the drive motor. Advance

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PPT slides 69 The control circuit receives it power from a Control Transformer that receives it primary power Advance by tapping off of L2 and L3 in the Power circuit. The transformer reduces the voltage from 480 volts down to 240 volts to be used safely for control purposes. Advance The output of the Control Transformer or its Secondary Side is connected to fuses 4FU and 5FU. These are known as Control Fuses and provide electrical protection for both the conductors and components in the Control Circuit Advance Following the circuit through 4FU , Wire 1 enters the Stop button which is a normally closed momentary contact. Advance

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PPT slides 69 The circuit continues out of the Stop Button on Wire 2 that goes to the Start Button which is a normally open momentary contact. Advance Leaving the Start Button our circuit now continues on to the Motor Contactor Coil on Wire 3. Advance The circuit is now completed leaving the Motor Contactor Coil on Wire 4 through the OL control contact Wire 5 which is connected to 5FU. Advance Take note of the extra contact designated M (Seal-In or Latch). This is to maintain the circuit to the Motor Contactor Coil once the Start Button is released. Otherwise each time the Start Button is pushed, the motor will start and each time it is released it will stop. Advance

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PPT slides 70 Pressing the Start Button will complete the circuit to the Motor Contactor Coil via points 1 through 3. The Motor Contactor Coil (M) is now energized which closes the Motor Power Contacts in the Power Circuit as well as the Seal-in Contact (m) in the control circuit. The motor will now start to run and continue to run until the Stop Button is pressed breaking the circuit to the Motor Contactor Coil (M). The reason the motor will continue to run and not drop off once the Start Button is released is because an alternative path is now made to the Motor Contactor Coil (M) through the Seal-In contact (m). Advance

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PPT slides 70 To stop the motor and break this circuit once it’s latched, press the Stop Button which will interrupt power to the Motor Contactor Coil (M) causing the Motor Power Contacts and Seal-In Contact to return to their normally open de-energized state. In the event of a motor overload, the Thermal Overloads in the Power Circuit will open up interrupting power to the motor as well as opening its associated control contact OL which breaks the circuit to the Motor Contactor Coil. Please note that before the Overloads can be reset, the source of the overload must be repaired in order to bring the drive motor circuit back to its normal condition. Advance

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PPT slide 71 The ___________circuit and the ___________ circuit are interdependent on each other and responsible for starting and stopping the elevator. a. power, control b. control, electrical c. power electrical d. lift, electrical Call on participants for answer Advance once given the correct answer Answer: a. Advance


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PPT slides 72 Contactors are part of the motor starter power switching devices. Advance Control relays are used as control switching devices because they are designed to withstand lower electrical currents. Motor starters are systems comprised of switching and overload-protection components. Advance

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PPT slide 73 Jim has been assigned to replace a geared motor unit, something he has never done before. Your job is to instruct Jim on how to complete this job. List the steps you would give Jim to successfully complete this task. [Allow participants to use their course book to review and list the steps on a sheet of paper. Discuss steps using the following slides.] Advance.

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PPT slides 74 Before removing a drive motor from the elevator, the elevator should be suspended in the hoistway by having the counterweight landed on the landing blocks in the pit. This will prevent any unintended movement. All electrical power should be removed and the machine should be locked and tagged out. Before disconnecting motor and control wires, all wires should be tagged. Disconnect the motor from the brake pulley. Remove lock down bolts that secure the motor to the base plate. Check for any shims under the base of motor. When using the same motor, count and separate the shims so that the same shims will go in the same location and order. The shims are there to correct any deviation in aligning the shafts. Advance

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PPT slides 75 When installing a new motor you must re-shim the base to align the shafts. A dial gauge or a laser aligner is used to get the proper alignment of the shafts. When properly aligned secure motor to the bed plate. Reconnect the pinflex coupling that align with the brake pulley. Reconnect the motor electrically ensuring that all windings are properly wired. Advance

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PPT slide 76 [At instructor’s discretion, take time to visit the field and look for examples drive motor systems. Advance.

Module Length: 450 min Time remaining: 90 min This section: 60 min Section start time: ________ Section End Time: ________

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PPT slides 77, 78 [Read slide. For each objective, briefly review what was learned in this module or ask participants to share what they have learned for each learning objective and briefly discuss as a class.] Advance. Lets take a look at some of the key words we have defined as moved through this module. Read slide. Discuss definitions as a group. Advance. Read slide. Discuss definitions as a group. Advance.


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PPT slide 79 Lets take a look at some of the key words we have defined as moved through this module. Read slide. Discuss definitions as a group. Advance. Read slide. Discuss definitions as a group. Advance. Read slide. Discuss definitions as a group. Advance.


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PPT slides 80 Administer quizzes.


CLASSROOM ACTIVITY Quizzes

Pencils

INDIVIDUAL ACTIVITY

Documents

Instructor Guide - Transit Training Network