How to know the back up time for a 5KVA UPS which is connected to 15 nos. of computers? Is there any formula for this? pls. tell me.

1 Answers   HAL,

---

What is the difference between resistance grounding system and resistance earthing system?

0 Answers  

---

When batteries are connected in series the voltage increases but the current remains unchanged, how can this be? When you consider ohm's law. i.e. If voltage increases, current increases, providing resistance remains the same.

10 Answers  

---

what do you mean by puncturing of insulator by ice -coating?

2 Answers  

---

In constant power region of 3-phase IM torque-speed characteristics, if frequency increases voltage A does not alter B decreases C increases D none of above

1 Answers  

---

How can i learn to programme every VFD. Or is there any typical study to understand VFD programming.

1 Answers   Volkswagen,

---

What is Earthing?

16 Answers   Essar,

---

i am BSEE student, my project study is to synchronize the generator of an hospital, it have a one 313KVA standby-power diesel gen.,and three 100kva transformer.The generator system is operated manually and no ATS or UPS. one more new building is being build so the transformer will be upgrade to a higher vale. 1)how i can connect the new gen. to the old gen. and to the synchronize panel? 2)what is the new gen. to be buy?(rating, etc.) These is my title: To synchronize the generator system of the ____ Hospital. Anyone have a good title? Thanks.

1 Answers  

---

my UPS is 600VA with 0.6 p.f and i use it for my computer which has 450W power supply unit, a monitor of 633nW and speakers. Can any one explain this.. because the output of UPS should be 360W (<450W)

2 Answers  

---

should dc supply will give the transformer to build up the voltage level

1 Answers  

---

In n high voltage 11kv system What happened if 1 of CT cable (IDMT) loose.Will e/f or o/c trip.please explain detail

1 Answers  

---

WHAT WILL HAPPEN WHEN THE MOTOR FREQUENCY INCREASED OVER THE RATED MOTOR RPM THROUGH DRIVE?

3 Answers  

---