Relay basics

you may find this link helpful.

http://www.wadeinstruments.com/relays/control_relay_tutorial.htm

How to Outline a Chapter

if you ever miss a unit/chapter/module review for a test, please use this link and follow the instructions.  an outline is NOT a list of underlined words and their definitions. missing work as always is due no later than 5 days after the original due date.

http://www.bemidjistate.edu/students/services/advising/resources/academic_toolbox/outline/

JUNIOR SHOP FINAL PRACTICE WORD PROBLEM

A customer has a machine that has four separate processes.  The first section requires a start button to be CLOSED in order for a magnetic motor starter with memory to become energized, which then energizes a light. The magnetic motor starter sends power to the second section.  In this section one NC and three NO buttons are used to control a control relay that also has memory.   The control relay sends power to the third section.  The third section contains one NC and two No pushbuttons.  Both pushbuttons must be CLOSED in order to energize a control relay with memory.  The relay will also energize an indicating light as well as send power to the fourth and final section.  This section consists of a limit switch controlling a magnetic motor starter with memory.  The customer also wants a safety stop switch installed so that the supervisor can shut the entire machine down. 

1.     Draw a line/ladder diagram and label and number all devices and lines.

2.     Create a price list for this job.  Use the attached pricing sheet and calculate how much time you think this job will take and how much per hour your labor is worth.

3.     The machine measures 200 feet in length ( each of the four sections measures 50 feet) and the supervisors office is 10 feet away from the machine.  All indicating lights are to be installed in the supervisors office.  Wire will be #14 AWG THHN solid copper.  The price list should be ONLY for the controls NOT any 3 phase for mags, etc.

4.     All devices will already be mounted in enclosures. Enclosures are installed two feet from the ends of each section and ten feet apart within the section.  Devices must be connected using liquidtight flexible metal conduit (seal-tite). Seal-tite will be secured using 2-hole 3/4" EMT straps with self-tapping sheet metal screws.

5.     Limit switches will require the use of 45 degree angle seal-tite connectors.  Stop/start stations will require 90 degree connectors.  All other devices including lights can use straight seal-tite connectors.

6.     An equipment ground must be pulled and connected to every device.

7.     Assume 120 volt power is available in the supervisors office and at the first location of the machine.

Some Pythagorean Theory Problems

now its time to practice what you've learned:

1. Find the length of the hypotenuse of a right triangle whose sides are 24 inches and 18 inches.

2. Find the length of a side of a right triangle whose hypotenuse is 17 yards and whose other side is 15 yards.

3. Find the distance that you would walk up a staircase if it is 21 feet high and has a base of 28 feet.

4. Find the perimeter of a flower garden if its shape is a right triangle with a hypotenuse of 10 feet and a side of 8 feet.

5. Find the hypotenuse of a sail whose shape is a right triangle with a base of 15 feet and whose height is 36 feet.

More Pythagorean Theorem help

some examples:

Example 1

Find the length of the hypotenuse of a right triangle if the length of its sides are 5 inches and 12 inches.

Solution 1

Example 2

A person drives 33 miles due east, then makes a left turn, and drives 56 miles north. How far is he from his starting point?

Solution 2

The right triangle is shown in Fig. 9-24.

Fig. 9-24.

Then

Pythagorean Theorem again

another explanation:

The Pythagorean Theorem

The Pythagorean theorem, an important mathematical principle, uses right triangles. A right triangle is a triangle which has one right or 90° angle. The side opposite the 90° angle is called the hypotenuse .

The Pythagorean theorem states that for any right triangle c ² = a ² + b ² , where c is the length of the hypotenuse and a and b are the lengths of its sides (see Fig. 9-23 ) .

Fig. 9-23.

Finding the Hypotenuse

If you need to find the hypotenuse of a right triangle, use c = .

Finding the Sides of a Right Triangle

If you need to find the length of one side of a right triangle, use a = or b = .

Angle Theta

some of you asked about this in class today.  here is some more information:

 How to Find the angle Theta:

Instructions

1. • 1
     Identify angle theta, the unknown angle in the triangle.
     
   • 2
     Identify sides "a," "b" and "c" of the triangle. Side "a" is the side opposite of the theta angle. Side "b" is the side adjacent to the theta angle. Side "c" is the hypotenuse, or the longest side, of the triangle.
     
   • 3
     Select a trigonometric identity to use to find angle theta, depending on the known side lengths. The trigonometric identities are:
     1. sin(theta) = a/c
     2. cos(theta) = b/c
     3. tan(theta) = a/b
     
   • 4
     Plug in the side lengths for the selected trigonometric identity to determine its ratio. For example, if side a = 6 and side c = 10, then sin(theta) = 6/10 or 0.6.
     
   • 5
     Using a scientific or graphic calculator, use the ratio of the identity to determine the measurement of angle theta. On the calculator, select the sin^-1, cos^-1, or tan^-1 key, depending on the trigonometric identity used, then type in the ratio from Step 4. The answer to this function is the measurement of angle theta. For example, if sin(theta) = 0.6, then sin^-1(0.6) = 36.9, and theta angle measures 36.9 degrees.
     

Read more: http://www.ehow.com/how_5075365_angle-theta-trigonometry.html#ixzz2rkOzWiOZ