Two Generators running in parallel, isolated from grid.

Contact Woodward Governor Company of Fort Collins, Colorado, U.S. They have an electronic governor paralleing control that will do what you want.

The alternative is to use a set of "Paralleling" lights or a "Synchroscope" to determine when to manually close the tie breaker when the generators are within the "Safe" window and the grid will pull the generators into synchronization due to the stronger power of the grid. The "Synchroscope" indicator should be rotating in the clockwise direction.

It is important to not try to close the circuit breaker outside the "Safe" window of the synchroscope or when the paralleing lights are illuminated as the generators are too far "out of phase" with the grid and you will damage your equipment due to the mechanical shock. You could break the engine crankshaft. That is why typically the "Synchroscope" has a permissive contact set that will only allow the breaker control to be actuated when it is safe to do so.

If you are doing it manually with just the "Paralleling" lights you run the risk of closing the breaker when it is too far out of phase; but it can be done safely if the Hz (Frequency) differenece between the grid and the generators is such that you get a very slow change in the "on-off" sequence of the the lights.(Lights must be off to close the circuiit breaker).

sounds like your system is capable to pull this off.but you might have inherited an overloaded to the system that someone do'nt understand,or your gov. sys. has a problem.Make sure you are getting the proper voltage to power your load and speed boards If you are you drooping below 60 hz, what you can do is remove all non-critical loads and ,....can you juggle the loads? I've been thru many scenarios at sea which are worse than the one you are describing.But here's my 2 cents.Until the gen's are slightly faster than utility,you have no chance and like the man said you will suffer from extreme mechanical damage when the gen's start motoring,watch your synchroscope, voltage on both the "grid" and your gens.Load sharing boards usually take care of this.I assume youhave a 2301A Woodward or the like.Get out your manual for droop and speed settings,Etc.You have to get your gen's runnig faster than utility by 1-2 hz.hopefully by removing loads ,and if your reverse current protection is working you have no worries,,even though,my exp. (after failure at sea,I had to take the utmost precautions.This stuff will kill you.Make sure guards and distribution covers are in place on all panels,and you are standing on an insulated matt If you are not sure ask the last operation engineer what to do,or the last vendor that worked on your system,forget the ego bull, this is some serious stuff your playing with.If you are not comfortable with this,call the vendors read your manuals, get farmiliar with your system,,I've done it many times! that's how I have learned most of my understanding of these systems.From people who know.Your boss will probably appreciate you more for it.that has been my experience,Skipper

.....and if your reverse current protection is working you have no worries........

Remember the "good old days," some of these young blokes have it too easy!!!!!

Having reverse current protection takes all the fun out of paralleling alternators..................even when you had a synchroscope, let alone the lamps (another 3 lamp method was the sequence method, the lamps brighten and darken in sequence, the correct moment to parallel was when the centre key lamp was dark and the other two lamps equally bright) ...........mind not on the job...........turn the oncoming alternator into a motor.................someting has to give..........and does............BANG

OR

Cannot agree more ............stranger things happen at sea!!!!!!!!

MOBI that's what I'm talking about!Those illustrations say it all. Is that the gen. input shaft I see that is twisted to a 90 deg. angle? Man that aint good.

My friend,

You should have two (2) sets synchroscope or synchronizing devices.

1. for your two (2) generators' output.

2. for your two (2) generators' output and the grid

The following should match up with:

1. Voltage

2. Frequency (Hertz)

3. Phase Angle

Eren