Generator Swithover Effects
- Thread starter adavey
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
They will all "de-energize" during the time the generator is starting up. When it comes on line, some may turn themselves back on automatically. Others will require operator action, in order to get them running again. The system should be designed such that the "important" loads come on by themselves, and such that the generator is not overloaded by the loads that restart automatically.
What exactly are you looking for?
What exactly are you looking for?
The bldg wants to remain fully operational during the event of a natural "DISASTER". I'm concerned that some equipment like hot water pumps, chilled water pumps and AHU's might have "stop start controls" that will de-energize upon power loss (assuming stop start controls are present).
Is a manual reset unavoidable ??????? I could run a relay but then I will compromise the "stop start" operability.
Is a manual reset unavoidable ??????? I could run a relay but then I will compromise the "stop start" operability.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
There manufacturers of "low voltage ride through" devices for motor control circuits. These are required in the semiconductor industry to meet SEMI F47.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
During a power failure, there will be 0 volts until the generator comes up to speed/frequency/voltage and is ready to accept load. During the 0 volt condition, many loads will drop out and need manual reset.
If you want to avoid the problem during the return transfer back to utility, you can specify a closed transition transfer switch.
If you want to avoid the problem during the return transfer back to utility, you can specify a closed transition transfer switch.
Bob NH
Senior Member
- Location
- The "Live Free or Die" State
Motor - Generator
Motor - Generator
I ran a desalting pilot plant in Wrightsville Beach, NC in the mid '70s that had frequent utility "power bumps" that were just enough to drop out the motor control circuits. It was a real nuisance to restart the whole plant.
We solved the problem by running the control circuits off a 115 Volt generator that was driven by an electric motor. There was enough inertia in the motor/generator to keep control power up during the "power bumps". In any longer outage, the system shut down normally.
In the modern systems you would probably use an Uninterruptable Power Supply.
It would require some attention to the controls so that sort of thing wouldn't CAUSE a problem.
Motor - Generator
I ran a desalting pilot plant in Wrightsville Beach, NC in the mid '70s that had frequent utility "power bumps" that were just enough to drop out the motor control circuits. It was a real nuisance to restart the whole plant.
We solved the problem by running the control circuits off a 115 Volt generator that was driven by an electric motor. There was enough inertia in the motor/generator to keep control power up during the "power bumps". In any longer outage, the system shut down normally.
In the modern systems you would probably use an Uninterruptable Power Supply.
It would require some attention to the controls so that sort of thing wouldn't CAUSE a problem.
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
Bob NH said:
If you have not been back since then, WOW it has grown.
charlie tuna
Senior Member
- Location
- Florida
most of the buildings today -- you mentioned chill water pumps -- have automated systems or building management systems. this would automatically restart the chillers and associated required motors and ahu's.. they have time out controls designed into them. this would add loads onto the generator in steps rather than restart everything at once!!!
ramdiesel3500
Senior Member
- Location
- Bloomington IN
Adding to Charlie's comments, if you have a control system that is capable of bringing motors back on (after an outage) in a staggered or stepped fashion, then you can actually reduce the size of the required engine generator unit resulting in a substantial cost savings to the owner. Otherwise, the generator unit required must be capable of starting all motors in the system at the same time!
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