Is a contactor (or master relay) required between incoming lines and a VFD? The question goes to safety. If a contactor were used before the VFD and an e-stop engaged then the motor will coast to a stop (i.e. VFD loses power) instead of stopping much faster if the VFD braking fucntion were used. It would make more sense to keep power on the VFD.

0 Answers   Pride Hotels,

---

I need a formula to calculate the size of cable as per load but in the terms of length. Please Reply me as i search lot of sites but i did not get the answer.

0 Answers  

---

how dia of wire and angles are calculated for overhead shielding wire to protect substation equipment from lightening strokes???

0 Answers  

---

how to calculate the slowness and fastness of energy meter if we have different kw load for example (0.746 kw and meter rev constant 400 and we calculate the 2 rev in 30 sec) please explain the formula thanks

1 Answers   WAPDA Water and Power Development Authority,

---

Any Electrical Engineering jobs?Please refer for interviews. Thank you

0 Answers  

---

---

If we tell 60 sq.mm. 3-1/2 core cable,then what does it mean ? 1) Each core section in the whole cable is of 60 sq. mm. 2) The whole cable is of 60 sq. mm. which is sub-divided into 3-1/2 core.

3 Answers   Cura HealthCare,

---

we all know voltage is a force(emf), and the force always devides if 2 or more than2 loads are there but why does the voltage remains same is parallel, it must devide na ???

0 Answers   NTPC,

---

DEAR SIR/MADAM,CLEARLY EXPLAIN ABOUT CRAWLING AND COGGING EFFECTS IN INDUCTION MOTOR.

0 Answers  

---

what is the difference between arc and spark

2 Answers  

---

why we can turn on the phase-A scr in 3 phase converter at 30 degrees

1 Answers   JSW,

---

when a machine act as genartor and as motor?

2 Answers  

---

how current flows in circuit?

11 Answers  

---