HT Motor Direction of Rotation (DOR) Changed

Electrical engineering root cause analysis (RCA) related to considered not possible HT motors’ Direction of Rotation (DOR) changed.

Note: This root cause analysis (RCA) is from real-time scenarios that happened in industries during the tenure of two or three decades ago. These articles will help you to improve your troubleshooting skills and knowledge.

HT Motor Direction of Rotation (DOR)

Why Direction of Rotation (DOR) arrows?

Large motors’ come with backward-curved fans (below figure). They deliver max air-flows at marked Direction of Rotation (DOR) and very little in the opposite DOR.

Consequently, the winding temperature could go a lot higher than permitted. It could shorten winding lives even lead to burnouts. This is especially serious, as most motors have no winding temperature indicators (at that time). Hence, DOR marks.

However, one can change DOR to suit the driven machine thus:

swap the left and right internal axial fans (IAF above-figure)
Substitute the existing External Radial Fan (ERF) with a purchased or homemade opposite curved vanes fan
Fix a new DOR indicating arrow
Interchange the two electrical leads as usual

Benefits of the RCA learned know-how

The plant used surplus motors gainfully and saved purchase costs for new applications.

Comments

What it is MQTT?

MQTT is an acronym for Message Queuing Telemetry Transport. It is a lightweight, publish-subscribe, machine to machine network protocol for message queue / message queuing service1. It is designed for connections with remote locations that have devices with resource constraints or limited network bandwidth, such as in the Internet of Things (IoT) . MQTT was created by Andy Stanford-Clark (IBM) and Arlen Nipper (then working for Eurotech, Inc.) in 1999. It was used to monitor oil pipelines within the SCADA industrial control system 1. The goal was to have a protocol that is bandwidth-efficient, lightweight and uses little battery power, because the devices were connected via satellite link which, at that time, was extremely expensive. MQTT is based on a client-server architecture, where a message broker acts as a server that receives all messages from the clients and then routes the messages to the appropriate destination clients . MQTT uses a publish-subscribe model, where clients...

Ferrules and Cross Ferruling

Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...

What is a Torbar? – Averaging Pitot Tubes

The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...

TILI Automation

Search This Blog