Richard Paes

Application considerations for class-1 div-2 inverter-fed motors

Application considerations for fixed-speed motors utilized in hazardous locations are not new to the electrical community and have been discussed previously and are relatively well known in the petroleum industry. Documented guidelines for these applications are currently established, are primarily centered on motor-temperature-rise limitations and the use of nonsparking fans in class-1 division-2/zone-2 locations. However, there are additional considerations when motors and their associated loads are on inverter supply. Items such as the effect on motor temperature rise when operating at reduced speeds for units without independently powered blowers, the effect of nonsinusoidal supply at the motor terminals on motor temperature rise as well as rotor voltage related phenomenon are relevant items. This paper identifies and provides guidelines particular to inverter-fed applications for class-1 division-2 installations.

Application considerations for class 1 div 2 inverter-fed motors

Application considerations for fixed-speed motors utilized in hazardous locations are not new to the electrical community and have been discussed previously and are relatively well known in the petroleum industry. Documented guidelines for these applications are currently established, are primarily centered on motor-temperature-rise limitations and the use of nonsparking fans in class-1 division-2/zone-2 locations. However, there are additional considerations when motors and their associated loads are on inverter supply. Items such as the effect on motor temperature rise when operating at reduced speeds for units without independently powered blowers, the effect of nonsinusoidal supply at the motor terminals on motor temperature rise as well as rotor voltage related phenomenon are relevant items. This paper identifies and provides guidelines particular to inverter-fed applications for class-1 division-2 installations.

Standard 1566 for (Un)Familiar Hands

IEEE Standard 1566: standard for performance of adjustable speed drives rated 375 kW and larger, was written to assist users, consultants, and manufacturers of large adjustable speed drives (ASDs). Users and consultants use it to specify a high-quality drive system and more easily compare proposals, while manufacturers easier to produce and compare. IEEE 1566 provides industry-wide alignment of terms that are commonly used in drive discussions as well as descriptions of various common drive functions and requirements.

Electrical System Design of Local Generator Applications Involving Adjustable-Speed Drives

The term local generator as used in this paper is intended to describe a dedicated generator supply to a specific facility which would have a more limited and specific capacity and loading than a broader and higher capacity utility supply. These systems, particularly when there is a large non-linear component, require additional coordination and design considerations as a result. Generator suppliers obviously understand their equipment in great detail and have well defined application guidelines for the more typical linear loads which they are expecting to supply. Adjustable speed drives and other non-linear loads bring additional factors into play such as harmonics, possible requirement for harmonics filters, and the specifics of their topology design such as the inherent capacitance involved in all drive designs. The intent of this paper is to address the necessary application considerations when applying non-linear loads on local generation starting at the basics of sizing and progressing through topics such as alternator sizing, voltage and speed regulation, etc. Specific focus will be with respect to an application issue which arose for a recent offshore application involving a high component of non-linear adjustable speed drive loading on their offshore distribution system per the authors experience.

Life cycle of a large adjustable speed drive system

This paper will discuss the many aspects and considerations for an adjustable speed drive (ASD) from inception through to the end of equipment life (cradle to grave). This paper will review best practices which may be new to young engineers and provide a comprehensive review for more experienced electrical engineers that would benefit from a refresher on the practices and standards. The different stages involved in the life cycle of an adjustable speed drive (ASD) and common issues which can arise will be discussed. While the focus of the paper is ASDs, many of the items will be relevant to projects in general and applicable to many facilities.

IEEE Standard 1566-2015 performance of adjustable speed AC drives rated 375 KW and larger

This paper presents the main revisions, updates, and additional materials that were added to the IEEE 1566 Adjustable Speed Drive standard first published in 2005. The revised standard addresses suggestions and additions received from end users, manufacturers, and consultants over the last 10 years and will reflect both field experience and advancements made. The paper also addresses the comprehensively revised and expanded data sheets available for completion by the purchaser and manufacturer. The data sheet is available in Excel format for ease of completion. A new section entitled “Technical Data Sheet Guide” explains the various terminologies used in the standard to help the user. Recommendations are made for future work.