What is CRT (Contact Resistance Test) for Isolators or Dis-
connector Switches? Why we performed it & whats the Testing
procedure.
Answer / deepak
ISOLATOR CONNECTOR DRAWS HIGH MAGNITUDE OF CURRENT. THE
MOVING AND FIXED CONTACT IF HAS HIGH CR THAN LOTS OF SPARK
AND HEAT WILL BE GENERATED WHICH MAY DAMAGE THE CONTACT
SURFACE AND REDUCE THE LIFE OF THE ISOLATOR CONTACT.
NORMALLY PETROLEUM JELLY IS APPLIED TO REDUCE THE CRT AND
for SMOOTH OPERATIONS. THE LOWER THE CRT BETTER IS THE LIFE
AND OPERATION OF ISOLATOR.
| Is This Answer Correct ? | 15 Yes | 1 No |
What are all the conditions to protect generator & turbine in thermal power plant?
why C.T protection required for H.T.lines?
What conditions are required for transformer to operate at low frequencies ?
Why we use two wattmeter during block rotor test and no load test of 3phase induction motor? And how can we understand the neat power requirement of from this test?
what is the basic difference between synchronous motor,synchronous generator and induction motor
1. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.
In siemens S7-300 PLC, what is function and function block ? What is the difference between them ? When to use function and when to use function block ?
what is the use of piston rings in the engine used for a generator...........
what is cogging and crawling
20 Answers ABB, Ashok Leyland, Bharat Bijlee, BMRCL, MN Dastur, Siemens,
What should be distance required in between two phase of HT cionductors in open area??????
why we use the fuse in only one wire? althrough in ac current the current flows in both directions. why the neutral wire can be taken half the magnitude of phase wire while same current returns from neutral wire?
If we increase frequency in transmission line in lieu of voltage what will happen?
Civil Engineering (5086)
Mechanical Engineering (4456)
Electrical Engineering (16639)
Electronics Communications (3918)
Chemical Engineering (1095)
Aeronautical Engineering (239)
Bio Engineering (96)
Metallurgy (361)
Industrial Engineering (259)
Instrumentation (3014)
Automobile Engineering (332)
Mechatronics Engineering (97)
Marine Engineering (124)
Power Plant Engineering (172)
Textile Engineering (575)
Production Engineering (25)
Satellite Systems Engineering (106)
Engineering AllOther (1379)