Connecting Three Generators In Series

I was also perplexed a bit, but then Tornado answered, so my thinking seemed right after all... they need to be in parallel, otherwise ALL of them need to be on all the time, right?

So each generator output is switched using the 4-pole EK contactor of appropriate rating. The coils of each of the contactors is wired through the 3-position selector switch to the appropriate control supply. Any one only will be on at a time.

So, is this what you mean? Or, are they really in series?

If you want to change from one generator to another, where will the contactor control supply come from? Not from the generators, since the contactor will drop off once that generator is switched off won't it? You may need a battery supply for this, which means you must specify the EK contactors with DC coils...they are available.

You have budget for Generator but not for ATS??...It is like you buy car but no budget for Tyre....I have no comment about your series connection.

You must set the droop characteristic of the mechanical governers to the same value. Doop is the diff in rpm between no load and full load divided by the rated rpm; usually a percentage of 2 to 5%. This means that the individual gensets will share the load according to their ratings.

Similarly the voltage regulators need to be set to share the reactive load. This depents on the type of regulators fitted - need to consult the manuals

Please don't start generators when armatures are in series. You may buy three more.

Hook them in parallel with all the required devices such as frequency meters, voltmeters etc...

I have no idea what the selector switch is for. Oh yeah, a suicide knob.

I'm not sure about the rotary switch, either. I doubt that it is switching output power from the generators. More likely it aligns the synchroscope (or synchronizing lights) according to the incoming generator. [?]

A least-cost system might use manually closed shunt-trip circuit breakers for each generator, with synchronizing lights in lieu of a synchroscope. I have operated paralleling switchboards of either type, but too far in the past to be an expert.

Some further detail on this system might help.

You mean neither serie nor parallel connection I guess, you want to supply your load from one generator at a time. if so, You may use the 3 ways rotary switch to energize the coils of your EK block contactors, with electrical interlocking between the 3 contactors, use normaly closed auxiliary contacts to prevent a contactor to close while any other is closed, you need two NC contacts on each contactor. your system still not 100% safe as there is no mechanical interlock between the contactors.... for your safety and safety of your equipment invest little more in an ATS ............... for the supply of coil, either you use an externel source as batteries as one poster suggest, or in lack of funds as it is the case, you can energize each contactor from a phase of corresponding generator before the contactor input Good luck and be safe

Better you connect the generators in parallel. As per condition of load, you can run one generator individual or in parallel( one or two) .

Oh,..man.,.. You already hired ABB EK series contractors for connection works. They will do it.

A person in a proper frame of mind knew that the generator outputs need to be paralleled / phased with one another for proper operation. It can be done using 3 sets of switching contactors, where the # of contacts for each contactor are determined by the # of output phases). The option of putting the generator on line, one by one or any combination thereof via a selector switch need a little bit of modification. Assuming all contacts are properly rated for both the relays and the contactor's current carrying capacities, it is possible to configure such set up. By individually controlling each contactor coils via another set of relays contacts where the relay coils are in turn switched by the rotary selector switch. i.e., rotary position 1 will switch the first gen., pos # 2 will add gen 2, etc. It is also possible to initially select a generator with a different capacity to match load requirement or a diff gen combination via this rotary switch, which will be limited only by the number generators and the # of available switch positions.