Cram Practice Test 2 #61

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M

ME->EE

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When a motor is directly connected to generator terminals, does that mean that the motor and generator are parallel?  I would've thought they would be in series.


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No picture so I assume the fault is between the M and G. Looking bach into the system from the fault they are in parallel.

 
I just did a run of the Cram for Exam Vol 2, and I came across this problem too. Like Dude99 stated, the fault isn't specified, and the solution suggests that the fault is in the middle of the gen-motor connection, since that explains why Zm and Zg are calculated as in parallel.

 
ME->EE said:
When a motor is directly connected to generator terminals, does that mean that the motor and generator are parallel?  I would've thought they would be in series.
Click to expand...
Think about the sequence diagrams for a generator and motor, and how they are connected. What would they look like if a fault occurred between them?

Also, I imagine the answer should be 0.95 / 0.166j.

 
Chattaneer PE said:
Think about the sequence diagrams for a generator and motor, and how they are connected. What would they look like if a fault occurred between them?

Also, I imagine the answer should be 0.95 / 0.166j.
Click to expand...
Yes I have fixed this typo in a newer version. The problem should state the voltage is 0.9 (Not 0.95).
But to the other question: If a generator has its terminals connected directly to the motor, why would you think they are in series? There is nothing that can be downstream of the motor.

 

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