Getting Current Reading of CIM_Tachometer in order to Get Fan Current Speed

Question

I am working on a project which supposed to include computer's fans status. Most of the properties I need can be acquired from the Win32_Fan class. Sadly, I couldn't find a way to use this class for getting the current reading of the fan speed. In the Win32_Fan MSDN page it is mentioned in the "DesiredSpeed" property that the current speed is determined by a sensor named CIM_Tachometer:

DesiredSpeed

Data type: uint64

Access type: Read-only

Qualifiers: Units ("revolutions per minute")

Currently requested fan speed, defined in revolutions per minute, when a variable speed fan is supported (VariableSpeed is TRUE). The current speed is determined by a sensor (CIM_Tachometer) that is associated with the fan using the CIM_AssociatedSensor relationship.

This property is inherited from CIM_Fan.

For more information about using uint64 values in scripts, see Scripting in WMI.

After I saw that, I searched for this Tachometer CIM sensor and found the following code snippet (which was taken from http://wutils.com/wmi/root/cimv2/cim_tachometer/cs-samples.html):

//Project -> Add reference -> System.Management
//using System.Management;

//set the class name and namespace
string NamespacePath = "\\\\.\\ROOT\\cimv2";
string ClassName = "CIM_Tachometer";

//Create ManagementClass
ManagementClass oClass = new ManagementClass(NamespacePath + ":" + ClassName);

//Get all instances of the class and enumerate them
foreach (ManagementObject oObject in oClass.GetInstances())
{
    //access a property of the Management object
    Console.WriteLine("Accuracy : {0}", oObject["Accuracy"]);
}

And so I tried implementing it in my code:

public static String[] GetFanInfo()
    {
        ManagementClass cSpeed = new ManagementClass
            ("\\\\.\\ROOT\\cimv2:CIM_Tachometer");   //Create ManagementClass for the current speed property
        ManagementObjectSearcher temp = new ManagementObjectSearcher("root\\WMI",
            "SELECT * FROM MSAcpi_ThermalZoneTemperature"); //Create management object searcher for the temperature property
        ManagementObjectSearcher mos = new ManagementObjectSearcher
            ("SELECT * FROM Win32_Fan"); //Create a management object searcher for the other properties
        string[] Id = new string[8]; //Preparig  a string array in which the results will be returned
        Id[0] = "Fan"; //First value is the category name
        foreach (ManagementObject mo in mos.Get())
        {

            Id[1] = mo["Name"].ToString(); //Name of the component
            Id[2] = mo["Status"].ToString(); //Component's status
            long vel = Convert.ToInt64(mo["DesiredSpeed"]); //Desired speed of the component
            Id[4] = Convert.ToString(vel); 
            bool s = Convert.ToBoolean(mo["variableSpeed"]); //Wheater or not variable speed are supported
            Id[5] = s.ToString();
            break;
        }
        foreach (ManagementObject obj in temp.Get())
        {
            Double temperature = Convert.ToDouble(obj["CurrentTemperature"].ToString()); //Fetching the temperature
            Id[3] = Convert.ToString((temperature - 2732) / 10.0) + " C";
        }
        foreach (ManagementObject sObject in cSpeed.GetInstances()) //Get all instances of the class and enumerate them
        {
            Id[7] = sObject["CurrentReading"].ToString(); //Getting the current reading
        }
        return Id;
    }

To my surprise, it seems that the whole section of the current reading is skipped during runtime. occur anyway!

My question is, why is this certain part skipped? Is the Tachometer a sensor which cannot be used? is it disabled for some reason?

Thanks ahead.

P.S.

I'm writing the program in Microsoft Visual Studio 2015 using winforms for the user interface.