Welcome to another tutorial about the 8960.
This video will introduce you to a function included in the 8968-20 function package called the Speed Sweep.
To get access to this function, make sure that your 8960-20 is equipped with the option 8968-20
which allows you to connect your module to LVDAC-EMS for remote control.
Proceed by selecting Dynamometer on the front panel of the 8960
then connect the 8960 to your computer using a USB Cable and then start LVDAC-EMS.
Once it is fully opened, click on this icon to open the four quadrant dynamometer/ Power supply windows
and select Speed Sweep in the functions selection list here.
Now, let's take a look at the settings of this function:
Start Speed: Set the speed of the first step of this function. Note that the value is in RPM.
Finish Speed: Set the speed of the last step of this function. Again, the value is in RPM.
Number of steps: Set the number of speed steps from 0 to 50.
This setting automatically divides the difference between the start and stop speed into the specified number of steps of equal length.
Step Duration: Set the time length of each step. This value is in second.
Record Data to table: By clicking ''yes'', you allow LVDAC-EMS to record the Data of the meters here
and print them in the Data table automatically for each step as long as your Data table is set correctly.
For information on how to set the Data table, please refer to the video on Data table and graph for the 9063 Data acquisition module.
Pulley ratio: Every Lab-Volt motor is equipped with a pulley for easy coupling that can vary in size from one motor to another.
The number you see here represents the number of notches of a pulley.
The left number is for the 8960's pulley and the right number is for the motor you want to couple to the 8960.
For the information in the meters here to be correct, you need to set the right pulley ratio here before testing.
In this case, the motor attached to the 8960 has a pulley of 24 notches. This is the right ratio.
Thermistor type: Choose the Thermistor type function for what you want to protect.
Type 1 is for NiMH batteries and type 2 is for the Lab-Volt motor.
Status: Indicates if the function is started or not.
Here are the meters showing the parameters at the shaft of the machine under test,
the single refresh and automatic refresh button and finally the Start/stop button to control the function.
You can also find here a graph explaining the function.
As you can see, the speed sweep is a function that allows a user to vary the speed of a motor you want to test
over several constant steps of speed contained in a range define by the user.
A good example of when to use this function would be for tracing the torque versus speed curve of a motor.
In this demonstration, I will be tracing that curve for an induction motor, in real time,
to give you a general idea of how easy it is with the speed sweep function.
All I have to do is to configure the data table and the graph so the data recorded using the speed sweep will be automatically printed in the graph.
Once done, I select my start and finish speed, which here is from 1800 rpm to 0 rpm.
I choose how much step I want; here 10 steps will be enough for a demonstration.
Then, I set the step time to 5 seconds, I select ''yes'' here to collect the data, I start the induction motor then start the function.
As the steps go down, you will see here the speed value going down and the torque value changing.
Each time the motor is about to go to the next step, LVDAC-EMS records the data found in those meters and print them in the data table.
Since this data table is all set and the graph is ready, you can see that the curve is building over time at each new speed step.
You can also see here all the data of these meters getting saved in the Data table automatically.
You can then draw the couple versus speed curve in less than a minute without manually writing down every data and changing the speed.
This function is easy to use and can save you a lot of time.
Please note that this function can also be used to test a motor coupled to a specific charge
over several speed condition in a very short or long period of time without being involved in the process once started.
That's it for this tutorial.