Transformer Bank Workshop
Sequence

Audience:		Electrical distribution line personnel, engineers, and line supervisors
Average Training Time:		60 to 120 minutes NOTE
Format/ Product Code:		CD-ROM (MPEG Video)/ TBSEQMPG
Content Producer:		Mastery Technologies, Inc.

OVERVIEW
This course is the third course in the “Transformer Bank Workshop” series. All the the courses in this series use full-screen, full-motion video.
When replacing an existing transformer bank with a new one, line personnel must connect the new bank to match the sequence—or rotation of the bank being replaced. There are two situations when matching bank rotation is important: When your workers intend to parallel the banks to avoid an interruption in the customer’s service during the change over. And when the customer has three-phase motors. Failing to match the sequence could create ruin for customers with three-phase motors. Motors would run backwards. Pumps could be damaged and their reverse action could contaminate materials in the customer’s process. An assortment of similar problems could also occur. Knowing how to determine bank sequence and how to change it will help your workers effectively deal with situations like this.
This “near hands-on” course conveys the knowledge of three-phase transformer bank sequence your workers need to be able to parallel two banks and replace an existing transformer bank without damage to customers equipment and processes which would result from a disruption in service or a failure to match sequence between the two banks.
The course uses clear and concise presentations, thirty-two interactions, and 3D animations to actively involve your workers in the instruction and to clarify sometimes difficult concepts. Your workers will actually practice with and test on life-like computer-simulated transformer banks. They will make all transformer bank connections with the mouse or touchscreen.
In this course your line personnel will learn more about phase sequence. They will learn what sequence is, how to determine the sequence of a bank by sketching its connections, and finally they will get a chance to apply their knowledge of phase sequence in several problem cases.
This course was produced in collaboration with Otter Tail Power Company and Gordon Solee, PE.  The program is based on Mr. Solee’s popular and respected “Transformer Hands-On Workshop”.

TOPICS
The course presents interactive instruction covering the following topical areas:

Phase Sequence

• What is Sequence?
• Three-Phase Motor Rotation

Determine Sequence

• Primary Connections
• Determining Secondary Sequence: Procedure
• Determining Secondary Sequence: Closed Banks
• Determining Secondary Sequence: Mixed Polarity
• Determining Secondary Sequence: Open Banks

Practical Application

• Match Sequence
• Three-Phase Transformers
• Primary Sequence

PERFORMANCE OBJECTIVES
This course will measure mastery on each of the following performance objectives. Upon completion, workers will be able to...

Describe when sequence must be considered

1. Cite customer requirements to maintain existing rotation for customer motors.
2. Explain how phase sequence affects motor rotation.
3. Relate reversal of customer motor rotation to damage to customer equipment and processes.

Determine bank sequence by inspection

1. Identify the sequence of two different closed secondary banks by inspection.
2. Identify the sequence of an open secondary bank by inspection.
3. Demonstrate the procedures for determining sequence.
4. Explain how sequence is changed.

Connect a bank to provide a specific sequence

1. Change the sequence of a delta secondary.
2. Change the sequence of an open delta secondary.
3. Change the sequence of a wye secondary.

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