Limbaja Energy

Electrical Motor Efficiency Study

Electrical Motor Efficiency Study

Overview

The motor efficiency can be calculated from the total losses, which are assumed to be the summation of the following losses.

Losses considered:

Constant losses, Core losses, Friction and Windage losses
Stator copper losses
Rotor copper losses
Stray losses

The stray losses are difficult to measure with any accuracy. IEEE Standard 112 gives a complicated method. Which is rarely used on shop floor. IS & IEC standards take fixed value as 0.5% of output. It must be remarked that actual value of stray losses is likely to be more. IEEE – 112 specifies values from 0.9 to 1.8%.

Case Study

Overview

  • Application: All Induction motor more than 50HP.
  • Type of Audit: Motor Efficiency Study.

Motor Efficiency Calculation

SNDescriptionsUnitValue
1No of poles-6
2Winding connection-DELTA
3Type-TEFC
4OutputkW180
5VoltageVolts415
6Full load current, IflAmp311
7Phase current at Full load, Ifl-phAmp179.6
8Speedrpm990
9FrequencyHz50
10Full load slipp.u.0.010
11Efficiency%90
12Insulation-Class F
13Full load winding temperature0C85
--No load test----
14Line voltage, UVolts415.67
15Line Current, InlAmp118.7
16Phase current, Inl-phAmp68.5
17No load power input, Pi-nlWatts9183
18Stator phase resistance at cold conditionOhms0.4333
19Stator phase resistance after no load testOhms0.4333
20Ambient Temperature, Ta0C30
21Frequency, fHz50
22Winding resistance at full load Rph-flOhms0.5233
--Calculation of losses----
23No load power input, Pi-nlWatts9183.33
24No load stator copper loss at T1 Temp.Watts6102.1
25Iron, friction and windage lossWatts3081.23
26Stator full load copper lossWatts50611.24
27Synchronous speed-1000.0
28Full load slip-0.01
29Rotor Input powerkW181.82
30Rotor ohomic losskW1.8
31Stray loss 1.5%kW2.7
32Total losskW58.21
33Motor full load input powerkW238.2
34Efficiency%75.563

Explore Related Services

Detailed Energy Audit
View Details
Detailed Energy Audit

Energy Audit is defined as “the verification, monitoring and analysis of use of energy including submission of technical report containing recommendations for improving energy efficiency with cost benefit analysis and an action plan to reduce energy consumption”. It builds on the principle "you can't manage what you don't measure". It essentially combines the principles of energy use and statistics.

Energy Conservation
View Details
Energy Conservation

Energy conservation is the effort made to reduce the consumption of energy by using less of an energy service. This can be achieved either by using energy more efficiently (using less energy for a constant service) or by reducing the amount of service used (for example, by driving less).

Harmonic Analysis
View Details
Harmonic Analysis

Harmonic analysis is a technique used to study and analyze the harmonic components in a periodic waveform or signal. The main use of harmonic analysis in electrical engineering is to examine the existence and properties of harmonics in electrical power systems. Harmonic voltage or current waveform frequencies are integer multiples of the fundamental frequency. However, due to non-linear loads, such as power electronics, variable speed drives, and certain types of lighting, harmonic currents and voltages can be introduced into the system.

Compressor Air Flow Audit
View Details
Compressor Air Flow Audit

A compressed air audit effectively identifies inefficiencies, reduces energy costs, and improves system performance. Many industrial air compressors operate inefficiently due to leaks, artificial demand, and incorrect air pressure requirements, unnecessarily increasing cost per kWh.

View All Services
Chat with us