Wiring of control power transformer for motor control circuits

Why use a Control Power Transformer?

The motor branch circuit is usually a segment of a larger electrical distribution network in an industrial plant. The motor circuit supplies the required power to the various control devices in order for them to operate. In some cases, the various control devices are operated at the same voltage as the motor.

Sometimes, the voltage required to operate the motor is too high to safely operate the control circuit, particularly in regards to personnel safety.

As a means of reducing the motor voltage to a safer control voltage level, we use a device known as a Control Power Transformer.

Connected with the Primary winding to the Power circuit – Secondary winding to the Control Circuit

A typical control transformer is shown in Figure 1 below. It consists of two separate coils of wire (windings) placed adjacent to each other on a common iron core. Note that the primary windingis connected to the power source. The secondary winding is connected to the control circuit. The purpose of the transformer is to transfer electric power from the primary circuit to the secondary circuit.

The transformer either reduces (steps down) or increases (steps up) the voltage to match the requirements of the control circuit.

Figure 1 – Typical Control Transformer

Magnetic field from primary winding induces voltage in the secondary winding.

Applying AC voltage to the primary winding of the transformer causes alternating current (AC) to flow in the winding.

This produces a magnetic field that extends outside the winding, in the shape of concentric loops as shown in Figure 2. The magnetic field fluctuates as the AC changes direction. These magnetic lines cut across the conductors of the secondary winding and induce a voltage.

Figure 2 – AC Flow in Windings

 

Voltages based on number of turns on both windings.

The relationship of the voltage across the primary to the voltage across the secondary is in direct proportion to the number of turns on both windings. For example, 100 turns on the primary, and 10 turns on the secondary, is a 10 to 1 ratio. If the primary is 500 volts, we will get 50 volts at the secondary.

This is referred to as a Step-Down transformer.

They are most commonly used in control circuits where the motor voltage is 480V, 600V, or higher. The step-down control transformer would reduce the voltage to pushbuttons or PLCs to 120V or even 24V.

A transformer with the reverse proportion of more turns on the secondary winding than on the primary is called a StepUp transformer. It will increase the voltage according to the ratio of turns.

Primary connects to the power circuit — Secondary connects to the control circuit.

The schematic symbol for the transformer is represented by two groups of “scallops” facing each other. These represent the primary and the secondary windings. The winding with the higher number of turns should be shown to have more scallops than the other to identify it as either a step-down or step-up transformer.

Figure 3 shows a basic control circuit with a step-down transformer added. Note that the main motor circuit operates at 480V, while the control circuit is at 120V.

The primary winding of the transformer is connected to two phases of the power circuit. The secondary winding is connected to the control circuit.

Figure 3 – Control Circuit with control power transformer (CPT)

Control Circuit Wiring of CPTs

Magnet Coil and Pilot Lights rated for same voltage as Secondary of Transformer.

When you are installing a Control Power Transformer into a starter, you must be sure that the magnet coil is rated for the same voltage as the secondary of the transformer. In addition, any pilot lights in this circuit must have the same voltage as the secondary.

Dual Voltage units shipped with connections made for the higher voltage.

When you are using a Control Power Transformer with a dual voltage primary, check the transformer connections to be sure that they match the voltage of your power source.

For example, Cutler-Hammer transformers with dual voltage primaries (i.e. 480V and 240V) are shipped with the transformer connections made to supply the higher voltage. If the lower primary voltage is required for your application, change the connections as shown on the nameplate of the transformer.

Remove wire “C”, if supplied, from starter’s control circuit. As discussed earlier in this booklet, if wire “C” is supplied on the starter (magnet coil voltages greater than 120V), you must remove it. This will convert the starter from Common Control to Separate Control.

Figure 4 – Control power transformer wiring diagram

The leads from the primary of the transformer are connected to L1 and L2 on the starter. In this way, the primary of the transformer is supplied with the same voltage as the power/motor circuit of the starter. The leads from the secondary of the transformer are connected to Terminal 1 of the remote pilot device, and terminal 96 on the Freedom Series overload relay (see Figure 4 above)

Eaton Cutler-Hammer Installing A Control Power Transformer in Enclosed Controls

• Reference // Basic Wiring for Motor Contol by EATON

What is a relay ? Internal architecture of a relay

1. ​Relays – Relays are switches that open and close circuits when actuates with an electrical signal.

   
   A switch is a device that can open and close when actuated manually,typically through a physical action by a person or an object.
   Relays are used in application where it is necessary to control one or more circuits by a power signals that may or may not be isolated from the circuits being controlled and when manual actuation is not possible or practical.
   

   

   
   
   
   
   
   
   
   Here is an electrical diagram of a switch.When switch is open the circuit is open or off.When switch is when is switch is closed the circuit is closed or on.
   

   

   
   
   
   
   
   
   
   
   When a switch can be actuated with an electrical signal ,the device is then typically refereed to as a relay. 
   

   

   
   
   
   
   
   
   
   
   The actuation of the relay will change the state of the contact from open to closed or vice versus,depending on the contact configuration.Each switch in a relay referred to as a pole.Relays may have one or more pole.The number of poles in a relay indicates the number of switches that are contained within the relay.Each pole may be configured as single or double throw,indicating the number of circuits that can be controlled per pole.
   
   Single throw means that the pole has an open state and a closed state.The relay will alternate between states when actuated.

   

   
   
   
   
   
   
   
   
   Double throw pole can control two circuits and alternate between one circuit being open while the other is closed and vise versus when actuated.
   

   

   A break is the number of places or contacts that a switch uses to open or close a single electrical circuit.All contacts are either single break or double break.
   A single break contact breaks an electrical circuit in one place,while a double break contact it in two places. Single break contacts are normally used when switching lower power devices such as indicating lights.Double break contacts are used when switching high power devices such as solenoids.

Energy saving opportunities – Smart Panels

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Contents  [hide]  1– How Smart Panels contribute to Energy Efficiency? 2– Examples of architectures with Smart Panels

Smart Panels are distribution switchboards which include the 3 key functions:

• Measure, with embedded and stand-alone metering and control capabilities,
• Connect, with integrated communication interfaces, ready to connect the electrical distribution system to energy management platforms,
• Save, i.e. provide Energy Efficiency benefits, through real-time monitoring and control, and access to on-line services.

With embedded metering devices, Smart Panels are the natural source of data within the electrical installation. Information can be made available on local display, or sent via communication network.

Interface devices are implemented so that communication is made simple and easy to install. The most advanced and efficient technologies are used:

• Modbus: for transmission of information inside switchboards, between components,
• Ethernet cable or wifi: inside buildings, connecting switchboard with computers,
• Ethernet on DSL/GPRS: connecting the electrical distribution system to on-line services.

Fig. K25: Example of communication device developed for smart panels (Com’X 200 energy data logger, Schneider Electric)

How Smart Panels contribute to Energy Efficiency?

Smart Panels are designed to monitor electricity in the installation right at the sources. This is the best way to know how energy is used. They are adapted to a large range of power: from final distribution, up to the main distribution board. They offer large possibilities of visualization, from local, up to cloud based integrated solution.

They provide on-site real time monitoring and control. The most essential information can be displayed locally: power, energy consumption, status of equipment, alarms… Control of switchgear is also possible: open, close, reset of protection devices…

Key data and functions are provided on local screen, on-site computer, remote control room or cloud-hosted platform:

• Detect demand peaks or abnormal energy usage,
• Plan long term energy usage,
• Provide trends on energy consumption, making savings possible,
• Provide information for corrective, preventive or predictive maintenance.

Information is made available on PC for the site manager using web pages accessible with standard browser. Access is also given to external experts for analysis and optimization.

Examples of architectures with Smart Panels

Systems for monitoring and energy control are physically very similar and overlap with the electrical distribution architecture whose layout they often replicate.

The arrangements shown in Figure K26 to Figure K29 represent possible examples and reflect the requirements typically associated with the distribution involved (in terms of feeder numbers, the amount and quality of energy required, digital networks, management mode, etc.). They help to visualise and explain all the various services which can be used to promote energy efficiency.

Fig. K26: Monitoring architecture for a small site which only supports sub-metering

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Fig. K27: Monitoring and control architecture for a company with several small sites

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Fig. K28: Architecture for large multiple-site arrangements

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Fig. K29: Monitoring and control architecture for a large, sensitive industrial site

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Fig. K30: Architecture for a large commercial site

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In addition, these diagrams make it clear that the choice of components is determined by the choice of architecture (for example, the sensors must be compatible with the digital bus). The reverse can also happen, however, if a technicoeconomic assessment of components installation costs and expected results shows that a different architecture is more cost-effective. In fact, the cost (in terms of purchase and installation) of these components, which sometimes have the same name but different characteristics, may vary widely and produce very variable results:

• A metering device can measure one or more parameters with or without using calculations (energy, power, cos ϕ).
• Replacing a standard circuit breaker with a circuit breaker containing an electronic control unit can provide a great deal of information on a digital bus (effective and instantaneous measurements of currents, phase-to-neutral and phase-to-phase voltages, imbalances of phase currents and phase-to-phase voltages, frequency, total or phase-specific active and reactive power, etc.).

When designing these systems, therefore, it is very important to define objectives for energy efficiency and be familiar with all the technological solutions, including their respective advantages, disadvantages and any restrictions affecting their application (see Fig. K31).
To cover all the various scenarios, it may be necessary to search through various hardware catalogues or simply consult a manufacturer offering a wide range of electrical distribution equipment and information systems. Certain manufacturers, including Schneider Electric, offer advisory and research services to assist those looking to select and implement all these various pieces of equipment.

	Energy savings	Cost optimisation	Availability and reliability
Variable speed drives
High-performance motors and transformers
Supply for MV motors
Power factor correction
Harmonics management
Circuit configuration
Auxiliary generators
Outage-free supply devices
Soft starting
iMCC
Architecture based on intelligent equipment Level 1
Specialised, centralised architecture for electricians Level 2
General/conventional, centralised architecture Level 3

Fig. K31: Solutions chart

Category: 

• Chapter – Energy Efficiency in electrical distribution

Energy saving opportunities – Lighting

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Contents  [hide]  1– Lights and electronic ballasts or LED technology 2– Reflectors 3– Lighting control 4– Centralised lighting management

Lighting can account for over 35% of energy consumption in buildings, depending on the types of activities carried out in them. Lighting control is one of the easiest ways to make substantial energy savings for a relatively small investment and is one of the most common energy saving measures.

Lighting systems for commercial buildings are governed by standards, regulations and building codes. Lighting not only needs to be functional, but must also meet occupational health and safety requirements and be fit for purpose.

In many cases office lighting is excessive and there is considerable scope for making passive energy savings. These can be achieved by replacing inefficient luminaires, by replacing obsolete lights with high-performance/low-consumption alternatives and by installing electronic ballasts. These kinds of approach are especially appropriate in areas where lighting is required constantly or for long periods and savings cannot be achieved by simply switching lights off. The time taken to recoup investments varies from case to case, but many projects require a period of around two years.

Lights and electronic ballasts or LED technology

More efficient lights may be a possibility, depending on the needs, type and age of the lighting system. For example, new fluorescent lights are available, although ballasts also need to be replaced when lights are changed.

New electronic ballast are also available, offering significant energy savings compared to the earlier electromagnetic ballasts. For example, T8 lights with electronic ballasts use between 32% and 40% less electricity than T12 lights fitted with electromagnetic ballasts.

However, electronic ballasts do have a number of points of attention compared with magnetic ballasts:

• Their operating frequency (between 20 and 60 kHz) can introduce high frequency conducted and radiated disturbances, which can interfere with power line communication devices for example. Adequate filters must be incorporated.
• The supply current of standard devices is highly distorted, so that typical disturbances linked to harmonics are present, such as neutral current overload. Low harmonic emission devices are now available, which keep harmonic distortion to less than 20 percent of fundamental current, or even 5% for more sensitive facilities (hospitals, sensitive manufacturing environments …).

The LED technology, introduced only a few years ago, offers significant prospects for progress, especially for smart control. LED are considered as the sustainable alternative solution to achieve energy savings objectives in the lighting sector.

This is the first lighting technology suitable for all fields (residential, service sector buildings, infrastructure …) providing great energy efficiency and smart management capability.

Other types of lighting may be more appropriate, depending on the conditions involved. An assessment of lighting needs will focus on evaluating the activities performed and the required levels of illumination and colour rendering. Many existing lighting systems were designed to provide more light than required. Designing a new system to closely fit lighting needs makes it easier to calculate and ultimately achieve savings.

Apart from the issue of savings, and without forgetting the importance of complying with the relevant standards and regulations, there are other advantages associated with retrofitting lighting systems. These include lower maintenance costs, the chance to make adjustments based on needs (office areas, “walk-through” areas etc.), greater visual comfort (by eradicating the frequency beat and flickering typically associated with migraine and eye strain) and improved colour rendering.

Reflectors

A less common passive energy efficiency measure, but one which is worth considering in tandem with the use of lights fitted with ballasts, is to replace the reflectors diverting light to areas where it is needed. Advances in materials and design have resulted in better quality reflectors which can be fitted to existing lights. These reflectors intensify useful light, so that fewer lights may be required in some cases. Energy can be saved without having to compromise on lighting quality.

New, high-performance reflectors offer a spectral efficiency of over 90% (see Fig. K18). This means:

• Two lights can be replaced by a single light, with potential savings of 50% or more in terms of the energy costs associated with lighting.
• Existing luminaires can be retrofitted by installing mirror-type reflectors without having to adjust the distance between them. This has the advantage of simplifying the retrofitting process and reducing the work involved, with minimal changes made to the existing ceiling design.

Fig. K18: Illustration of the general operating principle for high-performance reflectors

Lighting control

The passive energy saving measures described above leave further scope for making savings. The aim of lighting control programmes is to give users the required levels of convenience and flexibility, whilst supporting active energy savings and cost reduction by switching lights off as soon as they are no longer needed. There are a number of technologies available with various degrees of sophistication, although the time taken to recoup investments is generally short at six to twelve months. A multitude of different devices are currently available too (see Fig. K19).

Fig. K19: A selection of lighting control devices: timers, light sensors, movement sensors

• Timers to turn off lights after a certain period has passed. These are best used in areas where the typical time spent or period of activity is clearly defined (such as corridors).
• Occupancy/movement sensors to turn off lights when no movement has been detected for a certain period. These are particularly well suited to areas where the time spent or period of activity cannot be accurately predicted (storerooms, stairwells, etc.).
• Photoelectric cells/daylight harvesting sensors to control lights near windows. When sufficient daylight is available, lights are turned off or switched to night-light mode.
• Programmable clocks to switch lights on and off at predetermined times (shop fronts, office lights at nights and weekends)
• Dimmable lights to provide a low level of illumination (night light) at off-peak periods (e.g. a car park requiring full illumination until midnight, but where lower levels will suffice between midnight and dawn)
• Voltage regulators, ballasts or special electronic devices to optimise energy consumption for lights (fluorescent tubes, high-pressure sodium lights, etc.)
• Wireless remote control devices for simple and economical retrofitting of existing applications

These various technologies may be combined and can also be used to create a specific effect or atmosphere. For example, programmable lighting panels in meeting areas (for board meetings, presentations, conferences, etc.) have a number of different light settings which can be changed at the flick of a switch.

Centralised lighting management

Some of the lighting control systems currently available, such as those based on the KNX protocol, have the additional advantage of supporting integration into building management systems (see Fig. K20).

Fig. K20: An example of links established using Schneider Electric’s KNX system

If this type of system is to produce results, the design and implementation stage must begin with an audit of energy consumption and a study of the lighting system with a view to devising the best lighting solution and identifying potential reductions in terms of both costs and energy consumption. As far as this kind of technology is concerned, Schneider Electric also has solutions for offices as well as exterior lighting, car parking facilities, parks and landscaped gardens.

Category: 

• Chapter – Energy Efficiency in electrical distribution

Energy saving opportunities – Motors

​

Motors represent 80% of electrical energy consumption in the industry segment

Motorised systems are one of the potential areas where energy savings can be made.

Many solutions exist to improve the energy efficiency of these motorized systems, as described below. You can also refer to the white paper “Energy efficiency of machines: the choice of motorization”

Choice/replacement of the motor

Those wishing to improve passive energy efficiency often consider replacing motors as a starting point, especially if the existing motors are old and require rewinding.

This trend is reinforced by the determination of major countries to stop low-efficiency motor sales in the near future. Based on the IEC60034-30 Standard’s definition of three efficiency classes (IE1, IE2,IE3), many countries have defined a plan to gradually force IE1 and IE2 motor sales to meet IE3 requirements.

In the EU, for example, motors of less than 375 kW have to be IE3-compliant by January 2015 (EC 640/2009).

There are two reasons for replacing an old motor:

• To benefit from the advantages offered by new high-performance motors (see Fig. K13)

Fig. K13: Definition of energy efficiency classes for LV motors, according to Standard IEC60034-30

Depending on their rated power, high-performance motors can improve operational efficiency by up to 10% compared to standard motors. By comparison, motors which have undergone rewinding see their efficiency reduced by 3% to 4% compared to the original motor.

• To avoid oversizing

In the past, designers tended to install oversized motors in order to provide an adequate safety margin and eliminate the risk of failure, even in conditions which were highly unlikely to occur. Studies show that at least one-third of motors are clearly oversized and operate at below 50% of their nominal load.

However:
 –   Oversized motors are more expensive.
 –   Oversized motors are sometimes less efficient than correctly sized motors: motors are at their most effective working point when operating between 30% and 100% of rated load and are built to sustain short periods at 120% of their rated load.

Efficiency declines rapidly when loads are below 30%.
 –  The power factor drops drastically when the motor does not work at full load, which can lead to charges being levied for reactive power.

Knowing that energy costs account for over 97% of the lifecycle costs of a motor, investing in a more expensive but more efficient motor can quickly be very profitable.

However, before deciding whether to replace a motor, it is essential:

• to take the motor’s remaining life cycle into consideration.
• to remember that the expense of replacing a motor even if it is clearly oversized, may not be justified if its load is very small or if it is only used infrequently (e.g. less than 800 hours per year see Fig. K14).
• to ensure that the new motor’s critical performance characteristics (such as speed)are equivalent to those of the existing motor.

Fig. K14: Life cycle cost reduction for IE2 and IE3 motors compared to IE1 motors, depending on the number of operating hours per year

Operation of the motor

Savings can be made by: Replacing an oversized old motor with an appropriate high-efficiency motor Operating the motor cleverly Choosing an appropriate motor starter/controller

Other approaches are also possible to improve the energy efficiency of motors:

• Improving active energy efficiency by simply stopping motors when they no longer need to be running. This method may require improvements to be made in terms of automation, training or monitoring, and operator incentives may have to be offered. If an operator is not accountable for energy consumption, he/she may well forget to stop a motor at times when it is not required.
• Monitoring and correcting all the components in drive chains, starting with those on the larger motors, which may affect the overall efficiency. This may involve, for example, aligning shafts or couplings as required. An angular offset of 0.6 mm in a coupling can result in a power loss of as much as 8%.

Control of the motor

The method for starting/controlling a motor should always be based on a system-level analysis, considering several factors such as variable speed requirements, overall efficiency and cost, mechanical constraints, reliability, etc.

To ensure the best overall energy efficiency, the motor’s control system must be chosen carefully, depending on the motor’s application:

• For a constant speed application, motor starters provide cheap, low-energyconsumption solutions. Three kinds of starters can be used, depending on the system’s constraints:
  • Direct on line starter (contactor) 
  • Star Delta starter: to limit the inrush current, provided that the load allows a starting torque of 1/3 of nominal torque 
  • Soft starter: when Star Delta starter is not suitable to perform a limited inrush current function and if soft braking is needed.

Example of constant speed applications: ventilation, water storage pumps, waste water treatment stirring units, conveyors, etc.

LC1 D65A••	LC3 D32A••	ATS48••

Fig. K15: Motor starter examples: TeSys D Direct on line contactors, Star Delta starter, Altistart softstarter (Schneider Electric)

• When the application requires varying the speed, a Variable Speed Drive (VSD) provides a very efficient active solution as it adapts the speed of the motor to limit energy consumption.

It competes favourably with conventional mechanical solutions (valves, dampers and throttles, etc.), used especially in pumps and fans, where their operating principle causes energy to be lost by blocking ducts while motors are operating at full speed.

VSDs also offer improved control as well as reduced noise, transient effects and vibration. Further advantages can be obtained by using these VSDs in conjunction with control devices tailored to meet individual requirements.

As VSDs are costly devices which generate additional energy losses and can be a source of electrical disturbances, their usage should be limited to applications that intrinsically require variable speed or fine control functions.

Example of variable speed applications: hoisting, positioning in machine tools, closed-loop control, centrifugal pumping or ventilation (without throttle) or booster pumps, etc.

Altivar 12 (≤ 4 kW )	Altivar 212 (≤ 75 kW)	Altivar 71 (≤ 630 kW)

Fig. K16: Variable Speed Drives of various power ratings (Altivar range, Schneider Electric)

• To handle loads that change depending on application requirements, starters, VSDs, or a combination of both with an appropriate control strategy (see cascading pumps example Fig. K17) should be considered, in order to provide the most efficient and profitable overall solution.

Example of applications: HVAC for buildings, goods transport, water supply systems, etc.

The method for starting/controlling a motor should always be based on a systemlevel analysis, considering several factors such as variable speed requirements, overall efficiency and cost, mechanical constraints, reliability, etc.

Fig. K17 : Example of cascading pumps, which skilfully combine starters and a variable speed drive to offer a flexible but not too expensive solution

Category: 

• Chapter – Energy Efficiency in electrical distribution

IEGT (PPI & PMI)

​

An injection-enhanced gate transistor (IEGT) is a voltage-driven device for switching large current. Fabricating insulated-gate bipolar transistors (IGBTs) with high collector-emitter voltage (VCES) is difficult because of a sharp increase in on-state voltage in the high current region. To overcome this limitation, IEGTs are fabricated using a unique emitter structure. Additionally, the outstanding turn-off performance and the wide safe operating area of IEGTs make it possible to reduce the power consumption, shrink the size and improve the efficiency of equipment. IEGTs are ideal for industrial motor control applications that support today’s social infrastructure, including industrial drive systems and power converters. Toshiba’s IEGTs are available in press-pack type and module type packages. You can select IEGTs that best suit the power capacity and load characteristics requirements for your applications.

Target Applications

• Converters for High-Voltage Direct-Current (HVDC) Transmission
• Static VAR Compensators (SVCs)
• Middle-Voltage Inverters

• Rail traction
• Subways and Light-Rail Systems
• Windmill

Features of IEGTs

In addition to IEGT’s good performance, Toshiba is an only internal maker that has two kinds of package of IEGT as press-pack type and module type.

Considering each advantage of two kinds of package, Toshiba will respond customer’s needs.

And hybrid modules using a new material silicon carbide diodes will draw out advantages from their application.

• Principle of Operation
• Package ConceptProduct introduction

Principle of Operation

• Cross-sectional structure of an IGBT and the factors that limit its collector-emitter voltage

Figure A shows the cross-sectional structure of a conventional IGBT and the carrier distribution in the N-base region. The carrier concentration decreases monotonically across the N-base region from the collector electrode to the emitter electrode. In order to increase the collector-emitter voltage of an IGBT, a deep N-base region is necessary between the collector and emitter electrodes. However, a deep N-base region leads to an area with lower carrier concentration. The consequent increase in electrical resistance results in an increase in voltage drop and thus an increase in on-state voltage.

• Characteristics of the IEGT gate structure and the injection enhancement (IE) effect

Figure B shows the cross-sectional structure of and the carrier distribution in an IEGT. The IEGT has an IGBT-like structure with deeper and wider trench gates than the IGBT. This structure increases the gate-to-emitter resistance, preventing carriers from passing through the emitter side. Consequently, carrier concentration is enhanced near the emitter electrode in the N-base region. As this phenomenon has the same effect as carrier injection and accumulation, it is called the injection enhancement (IE) effect. This trench-gate structure helps reduce an increase in voltage drop even at high collector-emitter voltage rating.

 

Figure A Cross-Sectional View of and Carrier Distribution in an IGBT

Because carrier concentration near the emitter is low, an increase in the collector-emitter voltage rating leads to an increase in on-state voltage.

 

Figure B Cross-Sectional View of and Carrier Distribution in an IEGT

Carrier concentration near the emitter is enhanced near the emitter. Consequently, electron injection increases, reducing on-state voltage.

Package concept

Press-Pack package

Electrical connections using pressure High reliability due to hermetic sealing Outstanding parallel operation technology Rupture-resistant package structure

Plastic Case Module package

Easy-to-assemble plastic module casing Base plate made from a composite Al-SiC material

Product introduction

• Press-Pack IEGTs (PPIs)
• Plastic Case Module IEGTs (PMIs)
• Hybrid IEGT / SiC-SBD Modules

Press-Pack IEGTs (PPIs)

All electrical connections in a PPI are made using pressure. Without wire bonding, the PPI is less vulnerable to thermal fatigue. Using many PPIs in series makes it possible for a system to keep running uninterrupted even if a few PPIs fail due to an electrical fault or damage. This is because the collector and emitter electrodes of the failed PPIs are short-circuited. PPIs can be cooled from both the collector and emitter sides. Hermetically sealed in a ceramic and metal enclosure, the press pack is highly moisture-resistant and can be immersed in cooling liquid for efficient cooling.

Characteristics of PPIs

• Electrical connections using pressure

Multiple IEGT chips are placed in an array on the same plane, and individual IEGT chips are uniformly pressed from both sides using a molybdenum plate. The collector and emitter electrodes of each IEGT chip are brought into contact with the corresponding copper electrodes of the press pack enclosure via the molybdenum plate by applying mechanical pressure. This not only makes electrical connections and but also allows heat dissipation.

• High reliability due to hermetic sealing

Inert gas is hermetically sealed inside the press pack in order to prevent electrodes from being degraded due to oxidation. Thus, PPIs provide high thermal reliability.

• Outstanding parallel operation technology

The wiring inside the gate terminal plate is designed to switch all the parallel IEGT chips simultaneously so that they will not interfere with each other and oscillate when switching.

• Rupture-resistant package structure

IEGT chips are positioned on a resin frame to make them less prone to rupture even if a chip is melt and destroyed during switching.

PPI Installation Example

In the example shown at right, three series-connected PPIs are vertically stacked.

The PPI are placed between cooling fins, and pressure is applied from above and below to hold them firmly. An elaborate setup is necessary to ensure that pressure is uniformly applied across the PPIs. The spring helps reduce thermal contraction to keep a constant pressure.

PPI Product Lineup

Part Number	Package	Absolute Maximum Ratings			VCE(sat)(V)		VF(V)
		VCES (V)	IC (A)	Tj (˚C)	Max	Test Condition @IC (A) / VGE(V)	Max	Test Condition @IC (A) / VGE (V)
ST1200FXF24	PPI85B	3300	1200	125	4.2	1200 / 15	3.8	1200 / 0
ST750GXH24	PPI85B	4500	750	125	4.0	750 / 15	4.2	750 / 0
ST1200GXH24A	PPI85B	4500	1200	125	3.8	1200 / 15	–	–
ST1500GXH24	PPI125A2	4500	1500	125	4.0	1500 / 15	4.2	1500 / 0
ST2100GXH24A	PPI125A2	4500	2100	125	4.0	2100 / 15	–	–

Application Examples

Converters for High-Voltage Direct-Current (HVDC) Transmission

HVDC transmission is utilized to efficiently transmit renewable energy captured in remote places, for example, windmills on the sea, to the sites where energy is used. The generated AC voltage is converted to DC voltage and transmitted ashore over long distances or via submarine power cables. At the receiving end, the DC voltage is converted back into AC voltage to feed electricity consumers. PPIs are used for high-voltage converters.

Static VAR Compensators (SVCs)

SVCs are electrical equipments for improving electricity quality (e.g., power factor correction) on transmission networks. PPIs are utilized as high-voltage, high-current power devices for active SVC applications such as static VAR generators (SVGs) and static synchronous compensators (STATCOMs).

 

Middle-Voltage Inverters

PPIs, which allow series connection and double-sided cooling, are ideal for high-capacity inverter applications.

Plastic Case Module IEGTs (PMIs)

PMIs can be screwed onto a cooling fin, simplifying equipment assembly. PMIs incorporate an Al-SiC base plate with a low thermal expansion coefficient and have an optimal internal structure and parts. Consequently, they are less susceptible to thermal fatigue and provide an improved power cycling capability for prolonged service life. The PMI package uses a high-CTI* material that is less sensitive to tracking destruction in order to improve isolation voltage on the package surface.

*CTI (Comparative Tracking Index)

Characteristics of PMIs

• Easy-to-assemble plastic module casing

Many IEGT chips are soldered on a ceramic insulating board and wire-bonded to the module terminals. The plastic module is easy to use because it dissipates heat from one side and is internally insulated.

• Base plate made from a composite Al-SiC material

To ensure thermal reliability, the package has a composite aluminum silicon-carbide (Al-SiC) plate with a low thermal expansion coefficient on its underside.

PMI Installation Example

A compact inverter circuit can be created by using 2-in-1 PMIs that contain two IEGTs.

The example shown at right uses three 2-in-1 PMIs. The stray inductance can be reduced by using a laminated electrode plate.

PMI Product Lineup

Part Number	Package	Absolute Maximum Ratings			VCE(sat)(V)		VF(V)		Circuit Configuration
		VCES (V)	IC (A)	Tj (˚C)	Max	Test Condition @IC (A) / VGE(V)	Max	Test Condition @IC (A) / VGE (V)
MG1200V2YS61**	PMI142C	1700	1200	150	TBD	1200 / 15	TBD	1200 / 0	2 in 1
MG400FXF2YS53	PMI143C	3300	400	125	4.5	400 / 15	3.5	400 / 0	2 in 1
MG500FXF2YS61	PMI142C	3300	500	150	4.6	500 / 15	4.1	500 / 0	2 in 1
MG800FXF1US53	PMI143B	3300	800	125	4.5	800 / 15	3.5	800 / 0	1 in 1
MG1200FXF1US53	PMI193	3300	1200	125	4.5	1200 / 15	3.5	1200 /0	1 in 1
MG1500FXF1US62	PMI193D	3300	1500	150	3.8	1500 / 15	3.8	1500 / 0	1 in 1
MG900GXH1US53	PMI193	4500	900	125	4.7	900 / 15	3.8	900 / 0	1 in 1
MG1200GXH1US61	PMI193D	4500	1200	150	4.0	1200 / 15	3.6	1200 / 0	1 in 1

**: Under development

Application Examples

Rail traction

PMIs are suitable for inverter and converter applications that drive traction motors for rail transport systems, including the Shinkansen, rapid transits and urban rail transits. PMIs help improve efficiency and save energy.

Subways and Light-Rail Systems

PMIs are also used for inverter applications that drive rail traction powered by DC overhead lines.

Windmill

IEGTs are commonly used in the power converter for windmill that convert the power of wind into electricity.

Hybrid IEGT / SiC-SBD Modules

The requirements for rail traction motor control systems include not only low noise and comfortable ride but also compact size, light weight and energy efficiency. To meet these requirements, Toshiba has developed a Plastic Case Module IEGT (PMI) that incorporates silicon carbide Schottky barrier diodes (SiC-SBDs).

　SiC: Silicon Carbide
PMI: Plastic Case Module IEGT

Hybrid IEGT / SiC-SBD Modules Product Lineup

Part Number	Package	Absolute Maximum Ratings			VCE(sat)(V)		VF(V)		Circuit Configuration
		VCES (V)	IC (A)	Tj (˚C)	Max	Test Condition @IC (A) /VGE(V)	Max	Test Condition @IC(A) /VGE(V)
MG1200V2YS71	PMI142C	1700	1200	150	3.8	1200 / 15	3.5	1200 / 0	2in1
MG1500FXF1US71	PMI193D	3300	1500	150	3.8	1500 / 15	4.6	1500 / 0	1in1

Electrical Control Suspension

Aplication Block Diagram

 

Recommended Products

Function Block	Product Category	Package	Part Number
Solenoid, Motor Control	MOSFET	PS-8	From the sorted list for each package, you can choose the product.
		SOT-23
	Diode	S-FLAT	CRG07
Pre-Driver	IPD (Pre-Driver)	SSOP24	TPD7101F
		PS-8	TPD7102F

Contacts

If you have any questions, click one of these links:

Technical queries

• Inquiry sheet

Questions about purchasing, sampling and IC reliability

• Toshiba Global Sales
• For Online Purchase

Linear Power Supplies

​

Circuit Example

 

Features

• Linear power supplies are available in a wide range of packages from general-purpose SMV (SOT-25) to an ultra-small package with the industry’s smallest form factor measuring 0.8×0.8 mm. Those in the DFN4, SDFN4 and WCSP4 packages, which are most widely used for small portable applications, are offered with various current/voltage ratings and additional features.
  Additionally, the new LDO regulator series provides a significant reduction in voltage dropout thanks to reduced process geometries.

 

Application Examples

• Small portable devices
• Cell phones
• Portable audio
• Notebook PCs
• Digital still cameras
• Digital video cameras

Recommended Parts

Category	Series	Output Current (mA)	Output Voltage (V)	Features	Overcurrent Protection	Thermal Shutdown	Automatic Output Discharge	Package
LDO regulator	TCR2DGxx	200	1.2 to 3.6	Low noise High ripple rejection ratio	○	○	○	WCSP4
	TCR2ENxx	200	1.0 to 3.6	Standard type	○	–	○	SDNF4
	TCR2EExx		1.0 to 5.0		○	–	○	ESV
	TCR2EFxx		1.0 to 5.0		○	–	○	SMV
	TCR2LNxx	200	0.8 to 3.6	Low power consumption	○	–	○	SDNF4
	TCR2LExx				○	–	○	ESV
	TCR2LFxx				○	–	○	SMV
	TCR3DMxx	300	1.0 to 4.5	Low dropout voltage Low inrush current	○	○	○	DFN4
	TCR3DFxx				○	○	○	SMV

Package

SMV SOT-25 (2.8 x 2.9)	ESV SOT-553 (1.6 x 1.6)	DFN4 (1.0 x 1.0)	SDFN4 (0.8 x 0.8)	WCSP4 (0.79 x 0.79)

Contacts

If you have any questions, click one of these links:

Technical queries

• Inquiry sheet

Questions about purchasing, sampling and IC reliability

• Toshiba Global Sales
• For Online Purchase

DC-DC Converters (Isolated)

​

Circuit Example (Half-Bridge)

 

Circuit Example (Forward: Up to 200 W)

 

Circuit Example (Full-Bridge: Up to 1 kW)

 

Features

• Isolated DC-DC converters are widely used for applications in which there is a large difference between input and output voltages. Isolated half-bridge and full-bridge converters can handle up to 1 kW or so. Isolated DC-DC converters are used in power supplies for cell sites where direct-current distribution is utilized. They are used for both step-down and step-up voltage conversion.

Application Examples

• DC-DC converters for communication applications
• Regulated power supplies

Recommended Parts

Output Power			Up to 50 Forward	Up to 150 Half-Bridge	Up to 300 Full-Bridge	Up to 500 Full-Bridge	Up to 1000 Full-Bridge
DC-DC Conversion (Primary-Side Switch)	Low-Voltage Power MOSFETs	VDSS = 60 V			TPH4R606NH	TPH2R306NH	TPH2R306NH (2parallel)
		VDSS = 80 V			TPH8R008NH	TPH4R008NH	TPH4R008NH (2parallel)
		VDSS = 100 V			TPH8R80ANH	TPH4R50ANH	TPH4R50ANH (2parallel)
		VDSS = 150 V		TPN5900CNH TPH3300CNH
		VDSS = 200 V	TPN1110ENH TPH1110ENH	TPH6400ENH
		VDSS = 250 V	TPH1110FNH
DC-DC Conversion (Secondary-Side Switch)	Low-Voltage Power MOSFETs	VDSS = 30 V (Vout = 3.3 V)	TPN6R003NL TPN4R003NL	TPH1R403NL TPHR9003NL	TPHR9003NL (2parallel)	TPHR9003NL (4parallel)	TPHR9003NL (8parallel)
		VDSS = 40 V (Vout = 5 V)			TPHR8504PL	TPHR8504PL (2parallel)	TPHR8504PL (4parallel)
		VDSS = 60 V (Vout = 12 V)	TPN22006NH	TPN1400ANH TPN7R506NH	TPH5R906NH TPH4R606NH	TPH2R306NH	TPH2R306NH (2parallel)
		VDSS = 80 V (Vout = 12 V)	TPN30008NH	TPN13008NH TPH8R008NH	TPH4R008NH	TPH4R008NH (2parallel)	TPH4R008NH (4parallel)
		VDSS = 100 V (Vout = 12 V)	TPN3300ANH	TPN1600ANH TPH8R80ANH	TPH4R50ANH	TPH4R50ANH (2parallel)	TPH4R50ANH (4parallel)
		VDSS = 150 V (Vout = 24 V)	TPN5900CNH TPH5900CNH	TPH3300CNH	TPH1500CNH	TPH1500CNH (2parallel)	TPH1500CNH (4parallel)
		VDSS = 200 V (Vout = 36 V)	TPN1110ENH TPH1110ENH	TPH6400ENH	TPH2900ENH	TPH2900ENH (2parallel)	TPH2900ENH (4parallel)
		VDSS = 250 V (Vout = 48V)	TPN2010FNH TPH2010FNH	TPH1110ENH	TPH5200FNH	TPH5200FNH (2parallel)	TPH5200FNH (4parallel)
Output Error Feedback	Photocouplers	Analog feedback	TLP183, TLP293, TLP785
		Digital feedback	TLP2309, TLP2355, TLP2358

Contacts

If you have any questions, click one of these links:

Technical queries

• Inquiry sheet

Questions about purchasing, sampling and IC reliability

• Toshiba Global Sales
• For Online Purchase

Miniature Circuit Breaker or MCB

​What is MCB?

Nowadays we use more commonly miniature circuit breaker or MCB in low voltage electrical network instead of fuse.
The MCB has some advantages compared to fuse.

1. It automatically switches off the electrical circuit during abnormal condition of the network means in over load condition as well as faulty condition. The fuse does not sense but miniature circuit breaker does it in more reliable way. MCB is much more sensitive to over current than fuse.
2. Another advantage is, as the switch operating knob comes at its off position during tripping, the faulty zone of the electrical circuit can easily be identified. But in case of fuse, fuse wire should be checked by opening fuse grip or cutout from fuse base, for confirming the blow of fuse wire.
3. Quick restoration of supply can not be possible in case of fuse as because fuses have to be rewirable or replaced for restoring the supply. But in the case of MCB, quick restoration is possible by just switching on operation.
4. Handling MCB is more electrically safe than fuse.
   Because of to many advantages of MCB over fuse units, in modern low voltage electrical network, miniature circuit breaker is mostly used instead of backdated fuse unit.

Only one disadvantage of MCB over fuse is that this system is more costlier than fuse unit system.

Working Principle Miniature Circuit Breaker

There are two arrangement of operation of miniature circuit breaker. One due to thermal effect of over current and other due to electromagnetic effect of over current. The thermal operation of miniature circuit breaker is achieved with a bimetallic strip whenever continuous over current flows through MCB, the bimetallic strip is heated and deflects by bending. This deflection of bimetallic strip releases mechanical latch. As this mechanical latch is attached with operating mechanism, it causes to open the miniature circuit breaker contacts. But during short circuit condition, sudden rising of current, causes electromechanical displacement of plunger associated with tripping coil or solenoid of MCB. The plunger strikes the trip lever causing immediate release of latch mechanism consequently open the circuit breaker contacts. This was a simple explanation of miniature circuit breaker working principle.

Miniature Circuit Breaker Construction

Miniature circuit breaker construction is very simple, robust and maintenance free. Generally a MCB is not repaired or maintained, it just replaced by new one when required. A miniature circuit breaker has normally three main constructional parts. These are:

Frame of Miniature Circuit Breaker

The frame of miniature circuit breaker is a molded case. This is a rigid, strong, insulated housing in which the other components are mounted.

Operating Mechanism of Miniature Circuit Breaker

The operating mechanism of miniature circuit breaker provides the means of manual opening and closing operation of miniature circuit breaker. It has three-positions “ON,” “OFF,” and “TRIPPED”. The external switching latch can be in the “TRIPPED” position, if the MCB is tripped due to over-current. When manually switch off the MCB, the switching latch will be in “OFF” position. In close condition of MCB, the switch is positioned at “ON”. By observing the positions of the switching latch one can determine the condition of MCB whether it is closed, tripped or manually switched off.

Trip Unit of Miniature Circuit Breaker

The trip unit is the main part, responsible for proper working of miniature circuit breaker. Two main types of trip mechanism are provided in MCB. A bimetal provides protection against over load current and an electromagnet provides protection against short-circuit current.

Operation of Miniature Circuit Breaker

There are three mechanisms provided in a single miniature circuit breaker to make it switched off. If we carefully observe the picture beside, we will find there are mainly one bi – metallic strip, one trip coil and one hand operated on – off lever. Electric current carrying path of a miniature circuit breaker shown in the picture is like follows. First left hand side power terminal – then bimetallic strip – then current coil or trip coil – then moving contact – then fixed contact and – lastly right had side power terminal. All are arranged in series.

If circuit is overloaded for long time, the bi – metallic strip becomes over heated and deformed. This deformation of bi metallic strip causes, displacement of latch point. The moving contact of the MCB is so arranged by means of spring pressure, with this latch point, that a little displacement of latch causes, release of spring and makes the moving contact to move for opening the MCB. The current coil or trip coil is placed such a manner, that during short circuit fault the mmf of that coil causes its plunger to hit the same latch point and make the latch to be displaced. Hence the MCB will open in same manner. Again when operating lever of the miniature circuit breaker is operated by hand, that means when we make the MCB at off position manually, the same latch point is displaced as a result moving contact separated from fixed contact in same manner. So, whatever may be the operating mechanism, that means, may be due to deformation of bi – metallic strip, due to increased mmf of trip coil or may due to manual operation, actually the same latch point is displaced and same deformed spring is released, which ultimately responsible for movement of the moving contact. When the the moving contact separated from fixed contact, there may be a high chance of arc. This arc then goes up through the arc runner and enters into arc splitters and is finally quenched. When we switch on an MCB, we actually reset the displaced operating latch to its previous on position and make the MCB ready for another switch off or trip operation.

Video-Working of MCB