Using a VFD to load a genset.
Using a VFD to load a genset.
(OP)
I am looking for some advice on the above topic. We have an ABB regen drive (ACS800-11-0016-3) 15 kW and want to use it (in regen mode) to load a 3 phase diesel genset (18 kVA Cat/Olympian). We have had negative responses from ABB tech-help and a consultant. What issues can you see and what protection will be needed eg:
- preventing "islanding" in the case of power failure
- avoiding accidental "motoring" of the genset
- preventing "islanding" in the case of power failure
- avoiding accidental "motoring" of the genset
Engineering is the art of creating things you need, from things you can get.





RE: Using a VFD to load a genset.
Is motoring, aka 'dragging' the generator such a bad thing? If you need to avoid it, the torque limit can usually be set to allow only braking and no driving.
What are the specific reasons for not doing it that ABB and the consultant present?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Using a VFD to load a genset.
A load bank will only consume about 5 liters an hour so there is not a lot of financial incentive to avoid a load bank for testing.
The VFD will be easy to control.
Bill
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"Why not the best?"
Jimmy Carter
RE: Using a VFD to load a genset.
1. Start VFD
2. Set motor current to zero
3. Start genset
4. Select required (negative) torque or current setting on VFD to load genset.
Advantages of VFD over load bank
1. We already own this equipment. Load bank would need to be purchased
2. Stepless control
3. No heat to reject
4. Energy saving
ABB gave no reasons except "we don't have anyone using our drives for that". The consultant listed "motoring" and "islanding" as objections.
Engineering is the art of creating things you need, from things you can get.
RE: Using a VFD to load a genset.
I think you will have problems as the VSD software is designed to control an induction motor, where as you have a synchronous generator attached your diesel engine. I am reasonably sure that you will damage the VSD if you connect it to the output of your alternator, whilst the VSD control software does do flying start that is on an induction motor that has virtually zero voltage on the terminals when it is rotating. IF you were to get this to work you would have to have the VSD running and synchronise the output of the VSD with the output of the alternator, then close a contactor between the two. ABB does make a synchronising kit for VSD's and you use the VSD's PID control to synchroise the output. BUT why use a VSD to load a generator?, just synchronise the generator with the network and adjust the fuel supply, there are a lot of controllers out there, that do the just that and provide the network protection.
Skogs, ACS800-11 is a true line regen VSD with active front end, in this instance gruntguru has a 16kVA 400V wall mount regen version of the ACS800.
RE: Using a VFD to load a genset.
Engineering is the art of creating things you need, from things you can get.
RE: Using a VFD to load a genset.
I missed the synchronous generator part. All dynos I have seen have induction motors and connect to all regen drives with no problem.
But this is not a dyno. If there is no possibility to select synchronous machine operation, then it will not work.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Using a VFD to load a genset.
Permanent magnet synchronous motor
Only one permanent magnet motor can be connected to the inverter output.
It is recommended to install a safety switch between the permanent magnet synchronous motor and the drive output. The switch is needed to isolate the motor during any maintenance work on the drive.
Engineering is the art of creating things you need, from things you can get.
RE: Using a VFD to load a genset.
RE: Using a VFD to load a genset.
Engineering is the art of creating things you need, from things you can get.
RE: Using a VFD to load a genset.
RE: Using a VFD to load a genset.
Engineering is the art of creating things you need, from things you can get.
RE: Using a VFD to load a genset.
I used to work for ABB (with drives) and now work for a consulting firm, can I get paid for this
RE: Using a VFD to load a genset.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...