What is an energy-efficient motor

What is an energy-efficient motor?

An Energy efficiency motor produces the same shaft output power, but uses less input power than a standard efficiency motor.

Energy Efficient motors special?

Energy Efficient motor is manufactured using the same frame as a standard motor, but they have some differences:

-Higher quality and thinner steel laminations in the stator

– More copper in the windings.

– Optimized air gap between the rotor and the stator.

– Reduced fan losses.

– Closer machining tolerances.

– A greater length.

– High quality aluminum used in rotor frame.

Advantages

The Energy Efficient motor has a greater efficiency than a standard motors; therefore they have less operating costs.

Energy Efficient has a lower slip so they have a higher speed than standard motors.

Energy Efficient can reduce maintenance costs and improve operations in industry due to robustness and reliability.

Increasing the productivity.

Application considerations for High Efficiency Motors

Motor speed:

The average speed of an energy-efficient motor can be slightly higher than the average speed of an equivalent-sized standard-efficiency motor. Installing a new motor with a higher speed can result in reduced energy savings. For centrifugal pump or fan applications in particular, it is important to select a replacement motor that has a comparable full-load speed. It is also important to replace induction motors with induction motors and other types with their corresponding equivalent. Seek specialist advice if you want to change motor types.

Inrush current:

Overloading of circuits should be avoided. Energy-efficient motors will typically have a lower electrical resistance than a standard-efficiency motor, with the result that inrush currents will be higher. The duration of the inrush current is too short to trip thermal protection devices but could result in nuisance trips of in-built magnetic circuit protectors in some energy-efficient motors on start-up. The motor control and protection systems may need to be adjusted to match the new motor.

Here are the typical technical and commercial questions asked when assessing the viability of energy efficient motors for your operation.

Q: Are all new motors energy-efficient motors?

A: No, you generally have to ask for them

Q: Where can I buy an energy-efficient motor?

A: Energy-efficient motors can be purchased directly from most motor distributors. They can also be specified in any equipment package you may be ordering.

Q: Do energy-efficient motors require more maintenance?

A: No. Energy-efficient motors have the same maintenance requirements as standard motors and are often more reliable

Q: Are Energy Efficient Motors widely available? What is the range of Energy Efficient Motors available?

A: ABB Energy Efficient Motors are available off the shelf and can be manufactured according the specifications. Energy Efficient Motors are available in all speed ranges from 0.75 kW-700kW in low voltage.

Q: Can Energy Efficient Motors replace my existing motors on site?

A: Yes, any metric motor can be directly replaced by an Energy Efficient Motor. If you are replacing an imperial (inch frame) motor, some modification will be required

Q: Are Energy Efficient Motors available for hazardous area application?

A: Yes, because ABB uses the same energy efficient components across its complete range of 3 phase motors

Q: Should I rewind my standard efficiency motor or purchase an energy-efficient motor?

A: An energy-efficiency motor will result in lower energy costs when compared with a rewound motor. Its cost effectiveness will depend on the hours operated, motor efficiencies, utility rates, and the difference in cost between the rewind and the energy-efficient motor

Q: Can a standard motor be rewound as an energy- efficient motor?

A: It is possible for standard motor to have what is commonly called a high “efficiency rewind”. This rewind procedure can slightly increase the efficiency of a standard motor above its initial level. However, the efficiency would still be lower than that of a new energy-efficient motor because of its unique physical characteristics. Energy-efficient motors can also be rewound.

Q: How reliable are energy-efficient motors?

A: Energy efficient motors are as reliable as regular standard-efficiency motors. In some cases, they have a longer life because of lower motor operating temperatures.

Q: How much do energy-efficient motors cost?

A: Generally, they cost 10 to 20 percent more than standard motors, depending on the specific motor manufacturer, and market competition It may, however, be possible to negotiate a lower price premium when purchasing a large quantity of energy efficient motors.

Q: What is the power factor of an energy-efficient motor?

A: Power factors vary tremendously depending on motor loading and manufacturer. While some energy efficient motor models offer power factor improvements of 2 to 5 percent, others have lower power factors than their standard motor counter-parts. On the average, a power factor improvement of less than 1 percent is expected.

Q: What is the payback period for selecting an energy efficient versus a standard efficiency motor?

A: The payback period varies according to the purchase scenario under consideration, cost difference, hours of operation, electrical rates, motor loading, and difference in motor efficiencies
For new purchase decisions, the simple payback on the incremental cost of a continuously operated energy-efficient motor can be recovered through energy savings in less than 2 years.

Do energy efficient motors suffer a loss in efficiency when they are repaired?

A: Not necessarily. Efficiency losses can occur in either standard or energy efficient motors when poor quality control is observed. The core can be damaged by excess heat during winding removal. Any deviation from original wire gage and winding pattern generally increases losses. Machine work that alters original clearance and tolerance, and substitution of non-equivalent parts such as sealed bearings for shielded bearings can also reduce efficiency.

Q: Can Energy Efficient Motors be used on variable speed drive applications?

A: Yes, Energy Efficient Motors can be used for all the same applications as standard efficiency motors. For V.S.D. application, Energy Efficient Motors ran at lower temperature due to the thinner, low loss lamination steel, which reduces the harmful effects of harmonics

Q: Don't energy efficient motors always cost less to operate?

A: Add Your HeaEnergy efficient motors have a lower rotor and stator resistance and thus a higher inrush current and full-load speed than standard-efficiency motors. Speed changes significantly affect the power draw by centrifugal loads. The shaft power requirements for a centrifugal fan or pump loads varies as the cube of the speed while the flow of air or fluid discharge varies linearly with speed.
An increase in driven-equipment load can result in a greater power of kilowatt draw despite the lower inherent losses of the energy efficient motors.
The cost penalty due to operating at a higher full-load speed is related to load characteristics. For instance, a motor driving a pump which fills a reservoir tank may operate in an on/off mode. While the kilowatt draw may be higher, the operating time is reduced due to the provision of increased flow. In contrast, given a continuously operating system, the extra pumping capacity may be wasted in throttling and friction losses. The entire system of process should be examined prior to replacing a standard with an energy efficient motor. Also, not all energy efficient motors have higher speeds than their standard counterparts.

Q: Can I save money even when I only have relatively small motors in my plant?

A: The energy saving potential of small premium efficiency motors is actually greater percentage-wise than the savings on large motors. The reason is that on small motors, the percentage difference in efficiency between the standard motor and the premium efficiency motor is actually much greater than it is on larger motors

Q: When should we consider buying an energy efficient motor?

For all new installations

When going for equipment motor packages.

During Modification and Upgradation

Instead of rewinding older, standard efficiency units

To replace oversized and underloaded motors

As part of a PM or energy conservation program