Star-delta fan starter

The brief

Client

Kestrel Foundry

Site

Extract fan EF-2

Work order

KF-2603

Industry

HVAC

Task code

PLC-03

Difficulty

Foundation

Type of work

Programming

Sequence the three contactors of a star-delta starter: star for a set time, a short dead gap with both open, then delta, with stop dropping everything.

What you do

1. Read the client brief and the tag table: 5 tags, 2 inputs and 3 outputs.
2. Write the logic in ladder, Structured Text or SFC.
3. Press Simulate and watch the plant answer your program.
4. Run the factory acceptance test and fix what fails.

Skills you practise

• Timer sequencing
• Contactor interlocks
• Motor starting methods
• Reading a timing diagram

What the test checks

The factory acceptance test runs 4 numbered tests against your program. The numbers in the brief are drawn per learner. The tests are:

• Starts in star and stays there for the star time
• Changes to delta through a dead gap
• Stop opens all three contactors, in star or in delta
• Every start begins in star with the full star time

In this lab

• Ladder, Structured Text and SFC in one studio
• A plant that answers: motors, tanks, conveyors
• Numbered tests mark your program