# DC Bus Voltage

Discussion in 'Homework Help' started by resilient, Mar 19, 2009.

1. ### resilient Thread Starter Member

Feb 2, 2009
23
0
Can anyone give me a quick summary of what DC Bus Voltage actually is? I cannot actually find a good definition of it.

Thanks!

2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
283
A DC bus is a heavy conductor that distributes voltage. The bus voltage can be anything the circuit needs.

3. ### resilient Thread Starter Member

Feb 2, 2009
23
0
I see. So is there any difference between a DC bus and an infinite DC bus?

4. ### beenthere Retired Moderator

Apr 20, 2004
15,815
283
Can you give a definition of -
- ?

5. ### resilient Thread Starter Member

Feb 2, 2009
23
0
that's what i said... here's the full exam question so you have some context...

The output shaft of a separately excited DC motor is rigidly coupled to the shaft of an AC synchronous machine The DC supply for the DC motor is fixed at 60 V. The motor has an armature resistance of 0.5 Q and its field current is controllable. The AC machine has 4 poles and is star connected. It has a synchronous reactance of 200 Q per phase and the machine is connected to a 3 phase 50 Hz infinite bus with line voltage 380 V.

6. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
783
So - In fact it's a synchronous AC machine connected to an infinite AC bus. The infinite AC bus is one in which it is assumed that no matter how much current (better yet - energy) you put into or take out of it, its voltage, phase relationship and frequency remain unchanged.

It's a convenient means of analyzing certain synchronous machine modeling problems. It is an ideal construct that doesn't exist in reality but is helpful nonetheless.