Answer / nandan

The principle is that analyzer supplies a negative voltage
to transducer,who converts it into a frequency & sends it
across the probe.Now as the probe comes into the area of
rotor it creates a magnetic field & with it eddy current is
produced on the rotor side.Which changes the amplitude of
the frequency.It induces the voltage & remaining frequency
comes to the transducer through the return way.Transducer
converts it into the voltage .
Now coming back to the question The gap voltage has a
negative relation with the voltage induced i.e. as the gap
increases the induced voltage decreases.So to make it to
into a linear relation ship, negative voltage is supplied.
i.e

Gap Gap voltage
0 mm 0 vtg
1 mm -9 voltage
2 mm 18 voltage
& when the probe is in air it will have no induced voltage
so all -24 voltage without induced voltage will return back.

Answer / jigaranadkat

Because it has PNP transistor inside which requires base
bias of negative (-ve) supply.

Answer / darpan

The principle is that analyzer supplies a negative voltage
to transducer,who converts it into a frequency & sends it
across the probe.Now as the probe comes into the area of
rotor it creates a magnetic field & with it eddy current is
produced on the rotor side.Which changes the amplitude of
the frequency.It induces the voltage & remaining frequency
comes to the transducer through the return way.Transducer
converts it into the voltage .
Now coming back to the question The gap voltage has a
negative relation with the voltage induced i.e. as the gap
increases the induced voltage decreases.So to make it to
into a linear relation ship, negative voltage is supplied.
i.e

Gap Gap voltage
0 mm 0 vtg
1 mm -9 voltage
2 mm 18 voltage
& when the probe is in air it will have no induced voltage
so all -24 voltage without induced voltage will return bac

Answer / mohammed abbas

Because it is NPN tansistor during the initail days when
this was inveted by bently the cost of NPN transiator was
less. then they started use NPN transiator for the
vibration propbe, due to this we will give negative 24vdc
supply

Answer / shankar rao

negative feed back required.

Answer / sai kiran.c

does really negative voltage exists......???

why two probes are used in turbine flowmeters?

2 Answers  

what is absolute pressure, gauge pressure and atmospheric pressure?

2 Answers   Mother Dairy,

Why we use 3-15 psi air for control valve input?

2 Answers  

Consider a level troll. i am getting a correct value in 4mA and 20mA. the value in the middle(30 to 60%)is disturbed and i am not getting the appropriate value. what is the solution to normalize the level and to get the correct value..

2 Answers   KNPC,

what is power factor?

1 Answers  

Any can guide for QA/QC Inspector in oil & gas region, the procedures, formats standards, design criteria, i search in all enginees but i can't found wat i need?????????

4 Answers   Aramco, Asian Paints,

what is principal of pressure transmitter?

5 Answers   Hindalco, SPB,

What is the role of P(Protional), I(Integral) and D (Derivative) in PID Controller?

9 Answers  

What is difference between Ionization heat and bimetallic heat

0 Answers   KOC,

what is working principle of vibration prob

3 Answers  

what are the three main programming languages in plc

12 Answers  

Pls.could any one Clarify the following with an example. 1.At What condition Close on Rise and Close on Fall Pressure Switch contacts are used. 2.If Pressure is abnormal as per set pressure,if connecting Terminal of pressure switch breaks,how the voltage extends to Relay base. 3.Are these contacts come under fail safe philasaphy.

1 Answers