UK’s Leading Engineering Forum For Todays Engineer

Providing Regular Tips & Advice on Variable Speed Drives, Motors & Industry Related Topics

Jan
18
2018

What are the 10 different duty types (load cycle) of three-phase asynchronous motors?

Motor Duty / Load Cycle The term duty defines the load cycle to which the machine is subjected, including, if applicable, starting, electric braking, no-load and rest de-energized periods, including their durations and sequence in time. Duty considered as a generic term, for example, can be classified as continuous duty, short-time duty or periodic duty. …

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Dec
15
2017

What are the top safety tips for electrical engineers?

Seven steps that save lives// While we usually focus our weekly technical releases on practical assistance for today’s engineers, nothing is more important than understanding how to work safely. As an example of electrical safety procedures, we will discuss the safe working procedures used by HV field technicians – the ‘Seven steps that save lives‘. …

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Dec
15
2017

What are the key things to consider with the stop/start control of AC drives?

STOP/START control of the AC drive// The protection of the mains supply side of the drive requires a short-circuit protection. This can be, either in the form of a set of adequately rated fuses, usually as part of a switch-fuse unit, or a main circuit breaker. The stop/start control of the AC drive can be …

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Dec
14
2017

How do I select induction motors for industrial applications? (Part 3)

Design Considerations (cont.) Different Rotor Classes// The different rotor class, i.e. KL7, KL10, KL13, KL16, KLp, etc. are available in case of the motor to fulfil the functional torque requirements of the driven equipment. The rotor classes indicate against what quantum of the load torque the motor would be able to start easily. The motor …

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Dec
04
2017

How do I select induction motors for industrial applications? (Part 2)

Design Considerations (cont.) Motor Efficiency// The new IEC 60034-30 motor efficiency standard could have major energy-saving impact for industrial motors worldwide. Though standard motors are now available with a better efficiency, this factor (motor efficency) requires due attention when making the selection of the motor for a specific application in view of substantial quantum of …

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Nov
16
2017

How do I select induction motors for industrial applications? (Part 1)

Introduction to Induction Motors // All types of industries are invariably required to install different types of electric motors as the prime mover for driving process equipment in their respective production line up. The continuous process of technical development has resulted in the availability of highly diversified types of electric motors. Hence, the utmost care should …

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Nov
09
2017

What is the principle of power factor correction and protection of capacitors?

Power factor correction principle// Loads such as induction motors draw significant reactive power from the supply system, and a poor overall power factor may result. The flow of reactive power increases the voltage-drops through series reactances such as transformers and reactors, it uses up some of the current carrying capacity of power system plant and …

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Oct
05
2017

What are the basics of DC motors for electrical engineers?

General about DC motors// Separate field excitation DC motors are still sometimes used for driving machines at variable speed. These motors are very easy to miniaturise, and essential for very low powers and low voltages. They are also particularly suitable, up to high power levels (several megawatts), for speed variation with simple, uncomplicated electronic technologies …

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Sep
28
2017

AC versus DC – What’s the difference?

Take warning! Alternating currents are dangerous. They are fit only for powering the electric chair. The only similarity between an AC and a DC lighting system is that they both start from the same coal pile. And thus did Thomas Edison try to discourage the growing use of alternating current electric power that was competing …

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Sep
14
2017

What are the electrical characteristics of a motor?

Electrical characteristics of the motor// Electrical characteristics like voltage, frequency and phase of power supply should be consistent with the motor nameplate rating. A motor will operate satisfactorily on voltage within 10% of nameplate value, or frequency within 5%, with combined voltage and frequency variation not to exceed 10%. Voltage Common 60 hz voltages for …

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