Frequently Asked Questions

What are the components of an electric motor?

Understanding the components and operations of an electric motor is indeed crucial in comprehending energy usage and potential wastage within a business. An induction motor has several key components:

  • Conduit Box: Where the electrical input is applied, either from the mains/grid supply or a Variable Speed Drive (VSD).
  • Stator: The stationary part of the motor where the rotating magnetic field is generated when electrical power is applied. This field induces currents and associated magnetic fields in the rotor.
  • Rotor: The rotating part of the motor that interacts with the stator’s magnetic field, causing it to spin. This rotation is transferred to the output shaft (3).
  • Output Shaft: Transfers the rotational energy to the connected equipment or load.
  • Bearings: Support the rotating shaft, allowing it to spin freely.

When a motor is directly connected to an electrical supply, it draws a high current during startup, known as the ‘motor starting current.’ This initial surge of current creates heat, potentially leading to increased wear and reduced motor lifespan. Manufacturers often specify a maximum number of ‘starts’ per hour to prevent excessive heat buildup.

To mitigate this issue, soft starters or Variable Speed Drives (VSDs) can be used. These devices help limit the starting current, enabling smoother and more controlled starts, thereby reducing wear on the motor. By controlling the voltage or frequency supplied to the motor during startup, these technologies can significantly decrease the stress on the motor components.

Reducing the strain during motor startup not only prolongs the motor’s life but also contributes to energy efficiency within a business, as it minimizes energy wastage and operational wear and tear.

Why is the term Drive used in relation to electric motors?

The term drive is a common phrase used throughout the industry of electrical/mechanical engineering. It can be used in several different ways including describing motors, and drive systems such as gearbox and pulley systems. More so than others, the word drive often refers to a motor speed controller, commonly known as a Variable Speed Drive. The VSD is an electronic device that controls the electrical supply to a motor, allowing the frequency to be varied, enabling it to run at different speeds.

What is Energy Efficiency?

Sustainable Energy Ireland Motor efficiencies vary, being influenced by the design of the motor and its life history. In the UK and Ireland, modern motors are typically supplied in three efficiency grades, high efficiency (EFF1), standard efficiency (EFF2) and lower efficiency (EFF3), with about 4% difference between each. Older motors may be several efficiency points lower than standard efficiency motors and motors that have been rewound are also likely to have incurred a drop in efficiency. EFF1 motors are sometimes referred to as higher efficiency motors (HEMs). Enhanced Capital Allowance ABB EFF1 Motors qualify for 100 per cent first-year Enhanced Capital Allowances (ECA) UK, accelerated capital allowance Ireland, which allows the full cost of an investment in designated energy-saving plant and machinery to be written off against the taxable profits of the period in which the investment is made. The general rate of capital allowances for spending on plant and machinery is 20% a year on the reducing balance basis.

What is a Variable Speed Drive?

The basic function of a VSD is to control the flow of energy from the mains to the process. A VSD will sit between the electrical supply and the electric motor. The key aspect is that the power is fed from the electrical supply to the drive, and the drive regulates the power that is fed to the motor. This for example will then allow the motor to drive a pump or fan at a speed appropriate to the requirements of the process.

Besides saving energy, variable speed drives also help you reduce maintenance costs, waste, and even ambient noise emissions. They are also a great way to help meet your environmental goals.

What are the main methods of starting an electric motor?

There are several methods for starting a three phase squirrel cage electric motor. All applications will be different in terms of starting an electric motor, so it is important to understand each method. The below methods are the most used in the industry:

  1. Direct On Line (DOL) Start:

This is the most common starting method used in the industry. When the electric motor is started by direct connection to the power supply (DOL), it draws a high current, called ‘starting current’ which is approximately equal in magnitude to the locked rotor current. This starting method consists of only a main contactor, and thermal/electronic overload relay. The method draws the highest possible starting current, often around 6 to 7 times the rated motor current. These values are dependent on the motor size and design. During this method, the starting torque is significantly high, often higher than most applications require. This unnecessary high torque causes stress on the couplings and the driven application.

  1. Star / Delta Starting

This is a common method of starting an electric motor which reduces the starting current and starting torque. The device normally consists of three contactors, an overload relay, and a timer for setting the time in the star position (starting position). The received starting current is about 30% of the starting current during direct on line start and starting torque is reduced to about 25% of the torque available at a DOL start.

The motor must be delta connected during normal running. When reaching approximately 80-85% of the motor’s rated speed, the load torque is equal to the motor torque and the acceleration ceases. To reach the rated speed, a switch over to delta position is necessary, and this will often result in high transmission and current peaks. In some cases, current peak can reach a value that is even bigger than for a DOL start.

  1. Soft Starter

The Soft Start method has slightly different characteristics from other starting methods. It has thyristors in the main circuit and electric motor voltage is regulated with a printed circuit board. The soft starter makes use of the fact that when the motor voltage is low during start, so is the starting current and starting torque.

During the first part of the startup, the voltage to the motor is extremely low, only allowing the motor to adjust the play between the gear wheels or stretching driving belts or chains, leading to the elimination of unnecessary jerks during the start-up. The torque and voltage gradually starts to increase making the machinery begin to accelerate. A key benefit of this method is that you can adjust the torque to the exact need, whether the application is loaded or not. It is important to keep in mind that the full starting torque is available, but the soft start method is much more forgiving on the machine being driven, resulting in lower maintenance costs. Furthermore, the soft start has a stop-start function which is extremely advantageous. The soft stop function is useful to control the effects of fluid hammer often associated with uncontrolled pump stop – ultimately extending the pumps life and running costs. Additionally, the soft stop function is helpful for stopping conveyors, as it prevents the material getting damaged when the belt gets stopped quickly.

  1. Variable Speed Drive (VSD)

The basic function of a variable speed drive (VSD) is to control the flow of energy from the mains to the process. Variable speed drives sit between the electrical supply and the motor. Power from the electrical supply goes into a drive and the drive then regulates the power that is fed to the motor.

Inside the drive the input power is run through a rectifier, that converts the incoming AC power to DC power. The DC power is fed into the capacitors inside the drive. This is done to smooth out the electrical waveform which provides the clean power supply for the next step. Power then flows from the capacitors to the inverter, which changes the DC power to the output AC power that goes to the motor.

In basic terms, the drive consists primarily of two parts, one which converts AC (50 or 60 Hz) to DC and the second part which converts the DC back to AC, but now with a variable frequency of 0-250 Hz. As the speed of the motor depends on the frequency this makes it possible to control the speed of the motor by changing the output frequency from the drive.

For starting, a VSD can provide mostly all the benefits that a soft start can, offering not only an extremely smooth and controlled start, but also can efficiently can control motors to any desired level of speed and torque. VSD’s are also beneficial as you have the ability to run three phase motors of a single phase supply when it is the only supply available.

Are manufacturers allowed to produce IE1 motors after 16 June 2011?

Standard efficiency (IE1) motors may no longer be placed on the European market as of 16 June 2011. As of that date all new motors will have to meet the IE2 (high efficiency) rating in Europe. EU MEPS does not apply outside Europe. Manufacturers can continue to supply IE1 non-CE marked motors to customers located in Europe for further shipment to non-European markets. In this case a statement is required from the customer confirming that the motors’ final destination is outside Europe.

When I purchase a motor, how can I be sure that it meets the requirements of EU MEPS?

Check the motor rating plate and ask for the test report. The rating plate should be stamped with the efficiency class – IE2 as a minimum – and efficiency values (see Markings and documentation). The IE class stamped on the plate must be based on the lowest efficiency value at the rated voltage/frequency/output combination shown on the rating plate. In the case of ABB motors, the IE class and efficiency values are stamped on the rating plate and test reports are available on ABB’s website.The efficiency class stamped on the rating plate is verified using the testing methods specified in IEC 60034-2-1: 2007. ABB utilizes low uncertainty testing methods.

Does EU MEPS cover motors for explosive atmospheres?

No, EU MEPS does not cover all the types of motor covered by IEC 60034-30. Some motors (such as motors for explo­sive atmospheres) are included in IEC 60034-30 but exclud­ed from EU MEPS. As a global player, ABB will follow the requirements of IEC/EN 60034-30. Even though it is not required under EU MEPS, ABB will also provide IE markings for standard motors for explosive atmospheres.

Does EU MEPS cover marine motors?

No. Marine motors are designed for ambient temperatures outside the range -15°C…+40°C, specified in the Comission Regulation EC 640/2009.

Does EU MEPS cover brake motors?

No. Brake motors are excluded from the Comission Regulation EC 640/2009.

If a motor is rated for altitudes in excess of 1000 m does it fall within the scope of EU MEPS?

Yes, if the motor is of a standard type but de-rated for operation at altitudes in excess of 1000 m. No, if the motor has a special design (winding, fan, grease, etc.) for operation in excess of 1000 m.

Can a motor without IE marking be placed on the European market after 16 June 2011?

No. Motors placed on the market on 16 June 2011 or after must have the IE marking. Even if the motor was ordered before 16 June 2011 it cannot be delivered without the IE marking after 16 June 2011. ABB will roll out the new IE rated motors into all central stocks in time for the introduction of EU MEPS.

Can a motor be rewound and still be used after 16 June 2011?

EU MEPS does not regulate rewinding. As long as the motor has been placed on the market or put into service prior to 16 June 2011 it does not have to meet the minimum efficiency requirements. This means that when a motor fails the user has the normal choice between rewinding and replacement. Even though rewinding is still permitted, however, the user should carefully consider the advantages of replacing the motor rather than having it rewound. Each rewind normally reduces a motor’s efficiency by 1 – 3%. In many cases the payback period for a new motor is less than three years. A new high efficiency motor costs less over the long term, because the initial purchase cost is much lower than the lifetime operating expenses.

What does EU MEPS mean by ‘placed on the market or put into service?

The way these concepts should be understood is that ‘placing on the market’ (making a product available for the first time on the EU market) and ‘putting into service’ (first ABB LV Motors | EU MEPS for low voltage electric motors use of a product for its intended purpose by an end-user in the EU) refer to two different ‘moments’ in the process of bringing a product to the market. Compliance for entry into the market is required only once, based on the moment when the product is placed on the market or when it is put into service. Accordingly, Article 3 of the Ecodesign Directive (2009/125/EC) should be taken to mean that products covered by implementing measures may be placed on the market or put into service, or both, only if they comply with those implementing measures and bear CE marking in accordance with Article 5.A product has to comply with the requirements for CE marking from the moment that it is placed on the market. Only in cases where a product is not placed on the market in the literal sense shall the moment of compliance be the time when the product is put into service.As of 16 June 2011 motor manufacturers cannot ‘place on the market’ (sell) motors in Europe that are destined for final use in the EU market and do not meet IE2 efficiency levels. Motor users cannot ‘put into service’ (install) new motors that do not have the correct IE2/CE marking. However, users can install motors from their stock that were purchased before 16 June 2011.

As of 16 June 2011, are distributors or OEMs allowed to sell IE1 motors put into their stock previous to that date?

Yes, the EU legislation is not retroactive. These motors can be sold provided that they were put into stock or into the distribution chain before 16 June 2011. Products legally placed on the market can stay on the market and still be sold to the end-user and put into service.

Does EU MEPS apply to ‘dual purpose’ smoke extraction motors?

The answer depends on the type of motor:

– Yes, if the motor can be tested by the motor manufacturer at rated power and normal ambient with its own fan. This type of motor is covered by EU MEPS and must have the correct IE markings as of 16 June 2011.

– No, if the motor cannot be tested independently at rated power (ie, it requires a fan supplied by an outside manufacturer). These products – known as TEAO or Totally Enclosed, Air Over motors – are not covered by EU MEPS.

Does EU MEPS cover motors intended for VSD use?

Motors that can be used with a VSD and run direct on line (DOL) are covered by EU MEPS and must have the correct IE marking. Motors produced for VSD duty only (motors that cannot be run DOL), such as permanent magnet motors, are not covered and do not need an IE marking.

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